Статті в журналах з теми "Clinal pattern"
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1
UMINA, PAUL A., ARY A. HOFFMANN, ANDREW R. WEEKS та STEPHEN W. MCKECHNIE. "An independent non-linear latitudinal cline for the sn-glycerol-3-phosphate (α-Gpdh) polymorphism of Drosophila melanogaster from eastern Australia". Genetical Research 87, № 1 (лютий 2006): 13–21. http://dx.doi.org/10.1017/s0016672306007919.
Повний текст джерелаАнотація:
Latitudinal variation of the polymorphic sn-glycerol-3-phosphate (α-Gpdh) locus in Drosophila melanogaster has been characterized on several continents; however, apparent clinal patterns are potentially confounded by linkage with an inversion, close associations with other genetic markers that vary clinally, and a tandem α-Gpdh pseudogene. Here we compare clinal patterns in α-Gpdh with those of other linked markers by testing field flies from eastern Australian locations collected in two separate years. The α-Gpdh variation exhibited a consistent non-linear cline reflecting an increase in the α-GpdhF allele at extreme latitudes. This pattern was not influenced by the In(2L)t inversion wherein this locus is located, nor was it influenced by the presence of the α-Gpdh pseudogene, whose presence was ubiquitous and highly variable among populations. The α-Gpdh pattern was also independent of a cline in allozyme frequencies at the alcohol dehydrogenase (Adh) locus, and two length polymorphisms in the Adh gene. These results suggest clinal selection at the α-Gpdh locus that is partially or wholly unrelated to linear climatic gradients along the eastern coast of Australia.
2
Boussy, Ian A. "A latitudinal cline in P–M gonadal dysgenesis potential in Australian Drosophila melanogaster populations." Genetical Research 49, no. 1 (February 1987): 11–18. http://dx.doi.org/10.1017/s0016672300026677.
Повний текст джерелаАнотація:
SummaryIsofemale lines of Drosophila melanogaster from six localities along the east coast of Australia, spanning 2900 km and 26 degrees of latitude, were assayed for their gonadal dysgenesis characteristics in the P–M system of hybrid dysgenesis. A strong clinal pattern with latitude was discovered. From north to south, the first two populations were typical strong P populations, and the next population was moderate P. The next population to the south was neutral (Q), with some weak P and weak M characteristics. The two southernmost populations were typical M populations. Much variance in P activity in P populations and in susceptibility to P activity in M populations was detected among isofemale lines. This clinal pattern with latitude of the P–M system is paralleled by similar clinal patterns for frequencies of common cosmopolitan inversions and of certain allozymes in Australia. A model of introductions of flies with different characteristics in the north and south could account for the P–M clinal pattern, but cannot account for an intermediate Q population, nor establish the inversion and isoenzyme dines at the same time. Current models of transposable element population dynamics are limited to single population dynamics, and are therefore inadequate for these clinal data.
3
Prentice, Honor C. "Analysis of the clinal variation pattern inSilene latifolia (Caryophyllaceae) pollen morphology." Plant Systematics and Evolution 156, no. 1-2 (1987): 5–11. http://dx.doi.org/10.1007/bf00937197.
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4
HALLAS, REBECCA, MICHELE SCHIFFER, and ARY A. HOFFMANN. "Clinal variation in Drosophila serrata for stress resistance and body size." Genetical Research 79, no. 2 (April 2002): 141–48. http://dx.doi.org/10.1017/s0016672301005523.
Повний текст джерелаАнотація:
Clines for size and stress resistance traits have been described for several Drosophila species and replicable clines across different species may indicate climatic selection. Here we consider clines in stress resistance traits in an Australian endemic species, D. serrata, by comparing levels of variation within and among isofemale lines initiated with flies collected from the eastern coast of Australia. We also consider clinal variation in chill coma recovery, a trait that has recently been shown to exhibit high levels of variation among Drosophila species. Patterns were compared with those in the cosmopolitan species D. melanogaster from the same area. Both desiccation and starvation resistance showed no clinal pattern despite heritable variation among isofemale lines. In contrast chill coma resistance exhibited a linear cline in the anticipated direction, resistance increasing with latitude. Body size was measured as wing length and body weight. Both traits showed geographic variation and strong non-linear clines with a sharp reduction in size in the tropics. These results are discussed in the context of climatic selection and evolutionary processes limiting species borders.
5
Pigliucci, M., S. Benedettelli, and F. Villani. "Spatial patterns of genetic variability in Italian chestnut (Castanea sativa)." Canadian Journal of Botany 68, no. 9 (September 1, 1990): 1962–67. http://dx.doi.org/10.1139/b90-258.
Повний текст джерелаАнотація:
The spatial patterns of genetic variation for 15 loci in 18 Italian populations of chestnut were analyzed. Multivariate analysis and spatial autocorrelation analysis showed two clinal variations, one in a west–east direction, the other in a north–south direction. There was a nonrandom spatial pattern of at least three alleles and a marked heterogeneity among populations of many others. An explanation is proposed in terms of migration flow for the majority of the polymorphisms and of selection for the three autocorrelated alleles. However, anthropic interferences may also be important. Key words: chestnut, electrophoresis, spatial autocorrelation, correspondence analysis, genetic boundaries, discriminant analysis.
6
Berry, A., and M. Kreitman. "Molecular analysis of an allozyme cline: alcohol dehydrogenase in Drosophila melanogaster on the east coast of North America." Genetics 134, no. 3 (July 1, 1993): 869–93. http://dx.doi.org/10.1093/genetics/134.3.869.
Повний текст джерелаАнотація:
Abstract Clines may either be selectively maintained or be the by-product of nonadaptive processes related to population structure and history. Drosophila melanogaster populations on the east coast of North America show a latitudinal cline in the frequencies of two common electrophoretically distinguishable alleles at the alcohol dehydrogenase locus (Adh), designated Adh-S and Adh-F. This cline may either be adaptive or an artifact of a possible recent dual founding of North American D. melanogaster populations in which frequencies of Adh alleles differed between founder populations. By means of a high resolution restriction-mapping technique, we studied the distribution of 113 haplotypes derived from 44 polymorphic DNA markers within the Adh region in 1533 individuals from 25 populations throughout the cline. We found significant clinal differentiation at the polymorphism determining the mobility-difference causing amino acid replacement between Adh-F and Adh-S alleles. Hitchhiking was limited, despite extensive linkage disequilibrium, and other sites did not vary clinally. Such a pattern of differentiation implies that selection is responsible for the cline. To investigate whether selection acts only on the Adh-F/S site, we performed a "selective equivalence" test under the assumption that all variability within the specified allelic class is selectively neutral. This revealed selective equivalence among Adh-S-bearing haplotypes, whose frequencies showed no differentiation throughout the cline, implying high levels of frequency-homogenizing gene flow. Geographical heterogeneity among Adh-F-bearing haplotypes implied the action of selection on one or more additional variants in linkage disequilibrium with Adh-F. In a further study of a subset of the data (n = 1076 from 18 populations), we found a combined insertion/deletion polymorphism, designated delta 1, located in the 5' adult intron and in linkage disequilibrium with Adh-F, to show more marked clinal variation than Adh-F/S. Although the unequivocal identification of the precise target(s) of selection requires further study, we suggest that clinal selection may be acting epistatically on the Adh-F/S and delta 1 polymorphisms.
7
Umina, P. A. "A Rapid Shift in a Classic Clinal Pattern in Drosophila Reflecting Climate Change." Science 308, no. 5722 (April 29, 2005): 691–93. http://dx.doi.org/10.1126/science.1109523.
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8
Bridle, Jon R., Sedef Gavaz, and W. Jason Kennington. "Testing limits to adaptation along altitudinal gradients in rainforest Drosophila." Proceedings of the Royal Society B: Biological Sciences 276, no. 1661 (February 25, 2009): 1507–15. http://dx.doi.org/10.1098/rspb.2008.1601.
Повний текст джерелаАнотація:
Given that evolution can generate rapid and dramatic shifts in the ecological tolerance of a species, what prevents populations adapting to expand into new habitat at the edge of their distributions? Recent population genetic models have focused on the relative costs and benefits of migration between populations. On the one hand, migration may limit adaptive divergence by preventing local populations from matching their local selective optima. On the other hand, migration may also contribute to the genetic variance necessary to allow populations to track these changing optima. Empirical evidence for these contrasting effects of gene flow in natural situations are lacking, largely because it remains difficult to acquire. Here, we develop a way to explore theoretical models by estimating genetic divergence in traits that confer stress resistance along similar ecological gradients in rainforest Drosophila . This approach allows testing for the coupling of clinal divergence with local density, and the effects of genetic variance and the rate of change of the optimum on the response to selection. In support of a swamping effect of migration on phenotypic divergence, our data show no evidence for a cline in stress-related traits where the altitudinal gradient is steep, but significant clinal divergence where it is shallow. However, where clinal divergence is detected, sites showing trait means closer to the presumed local optimum have more genetic variation than sites with trait means distant from their local optimum. This pattern suggests that gene flow also aids a sustained response to selection.
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Silva, Gonçalo, Fernando P. Lima, Paulo Martel, and Rita Castilho. "Thermal adaptation and clinal mitochondrial DNA variation of European anchovy." Proceedings of the Royal Society B: Biological Sciences 281, no. 1792 (October 7, 2014): 20141093. http://dx.doi.org/10.1098/rspb.2014.1093.
Повний текст джерелаАнотація:
Natural populations of widely distributed organisms often exhibit genetic clinal variation over their geographical ranges. The European anchovy, Engraulis encrasicolus , illustrates this by displaying a two-clade mitochondrial structure clinally arranged along the eastern Atlantic. One clade has low frequencies at higher latitudes, whereas the other has an anti-tropical distribution, with frequencies decreasing towards the tropics. The distribution pattern of these clades has been explained as a consequence of secondary contact after an ancient geographical isolation. However, it is not unlikely that selection acts on mitochondria whose genes are involved in relevant oxidative phosphorylation processes. In this study, we performed selection tests on a fragment of 1044 bp of the mitochondrial cytochrome b gene using 455 individuals from 18 locations. We also tested correlations of six environmental features: temperature, salinity, apparent oxygen utilization and nutrient concentrations of phosphate, nitrate and silicate, on a compilation of mitochondrial clade frequencies from 66 sampling sites comprising 2776 specimens from previously published studies. Positive selection in a single codon was detected predominantly (99%) in the anti-tropical clade and temperature was the most relevant environmental predictor, contributing with 59% of the variance in the geographical distribution of clade frequencies. These findings strongly suggest that temperature is shaping the contemporary distribution of mitochondrial DNA clade frequencies in the European anchovy.
10
RISCH, SARAH, and JOS SNOEKS. "Geographic variation in Neolamprologus niger (Poll, 1956) (Perciformes: Cichlidae) from Lake Tanganyika (Africa)." Zootaxa 1857, no. 1 (August 27, 2008): 21. http://dx.doi.org/10.11646/zootaxa.1857.1.2.
Повний текст джерелаАнотація:
Intraspecific morphological variation in Neolamprologus niger from seven localities along the north-western shoreline of Lake Tanganyika (Luhanga, Bemba, Ubwari West, Ubwari East, Yungu, Kabimba and Kalemie) was investigated. As a result of geographical variation, the populations could be categorized into a northern, a central and a southern group. A clear clinal pattern was found for several meristics and measurements. The lack of knowledge on the geographical variation in African cichlids and its implication for further taxonomic research is discussed.
11
Rojas-Soto, Octavio R. "Geographic Variation of the Curve-Billed Thrasher (Toxostoma Curvirostre) Complex." Auk 120, no. 2 (April 1, 2003): 311–22. http://dx.doi.org/10.1093/auk/120.2.311.
Повний текст джерелаАнотація:
Abstract Geographic patterns of variation in morphological characters in the Curve-billed Thrasher (Toxostoma curvirostre) have been recognized by the description of seven subspecies. Twelve standard measurements, as well as three colorimetric characters and two color pattern characters, were analyzed to test whether subspecies limits predict patterns of variation. Measurement error was addressed by measuring each character three times and calculating the mean. A total of 821 male study skins were used, representing 29 locations. A variety of analysis revealed two major groups, an eastern and western group, divided by the Sierra Madre Occidental. Those two groups had previously been recognized as the curvirostre and palmeri groups, respectively. Those groups were also recovered by analysis of mtDNA. The two groups fulfill the requirements for species. The Tiburón Island (T. c. insularis) sample was distinct for several characters; however, small sample size precludes formal taxonomic recommendation. Within the two major groups, most characters showed incongruent clinal patterns of variation that did not match subspecies limits.
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Isler, Morton L., Phyllis R. Isler, and Robb T. Brumfield. "Clinal Variation in Vocalizations of an Antbird (Thamnophilidae) and Implications for Defining Species Limits." Auk 122, no. 2 (April 1, 2005): 433–44. http://dx.doi.org/10.1093/auk/122.2.433.
Повний текст джерелаАнотація:
Abstract In avian taxa in which vocalizations are considered innate, such as suboscine passerines, vocal characters are increasingly being used to help determine whether populations have achieved species status. In comparing vocal characteristics of distant populations, however, one must be concerned with the possibility of character gradation through intermediate populations. The first quantitative study of a species in a suboscine family to test for clinal vocal variation, our vocal study found clinal variation in the pace (number of notes per second) of male loudsongs, and revealed that the geographic pattern of the clines was consistent with genetic variation found in the companion molecular study (Brumfield 2005). The result underscores the necessity of searching for intermediacy when analyzing vocalizations of geographically distant populations. Furthermore, given that male loudsong pace was the only vocal character that varied across the intergrading populations, the result also provides support to the guideline that one should expect thamnophilid species to differ in at least three vocal characters (Isler et al. 1998) and indicates that this degree of vocal character differences can be a valuable “yard stick” in determining which thamnophilid populations have achieved biological species status.
13
Yates, Adam G., Robert B. Brua, Joseph M. Culp, Roger G. Young, and Patricia A. Chambers. "Variation in stream metabolism and benthic invertebrate composition along longitudinal profiles of two contrasting river systems." Canadian Journal of Fisheries and Aquatic Sciences 75, no. 4 (April 2018): 549–59. http://dx.doi.org/10.1139/cjfas-2016-0198.
Повний текст джерелаАнотація:
Our study aimed to determine drivers of longitudinal variation in stream metabolism and benthic macroinvertebrate (BMI) composition and assess concordance of these ecological measures for two Canadian rivers (Rat River and Tobacco Creek). Gross primary production was associated with longitudinal position in both rivers but also with the percentage of the watershed used for agriculture and hydrogeomorphic zone. However, within- and among-zone differences in stream metabolism indicated that longitudinal variation followed a staircase pattern rather than a clinal pattern. BMI composition was associated with network position in both rivers, but hydrogeomorphic zones were only important in Tobacco Creek. Among-zone differences in BMI communities in Tobacco Creek depended on season. Concordance between stream metabolism and BMI composition was not observed within either river despite metabolism and BMI composition being associated with longitudinal position. For these rivers, segment-scale hydrogeomorphic conditions appear to be important modifiers of longitudinal patterns observed at the whole river scale. The lack of concordance between stream metabolism and BMI composition suggests reach-scale processes are driving ecological differences within sampling sites.
14
Sielezniew, Marcin, and Izabela Dziekańska. "Geographical Variation in Wing Pattern inPhengaris(=Maculinea)Arion(L.) (Lepidoptera: Lycaenidae): Subspecific Differentiation or Clinal Adaptation?" Annales Zoologici 61, no. 4 (December 2011): 739–50. http://dx.doi.org/10.3161/000345411x622561.
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15
COLOMBO, Pablo C., and Maria I. REMIS. "Phenotypic pattern over centric fusion clinal variation in the water-hyacinth grasshopper, Cornops aquaticum (Orthoptera: Acrididae)." European Journal of Entomology 115 (June 20, 2018): 303–11. http://dx.doi.org/10.14411/eje.2018.029.
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16
Bahar, Nawa. "Studies on seed source variation in Albizia lebbeck (L.) Benth." Indian Journal of Forestry 31, no. 3 (September 1, 2008): 417–22. http://dx.doi.org/10.54207/bsmps1000-2008-cet75f.
Повний текст джерелаАнотація:
Source variation study of Albizia lebbeck was undertaken to identify the superior seed sources for production of quality seedling. Twenty nine seed sources sampled from the greater part of its natural range. Variation for most of the studied characters indicated non-clinal pattern. On average, the population of Dehra Dun (Uttarakhand), Kathua (Jammu & Kashmir) and Tirunelveli (Tamil Nadu) were found to be the best on the basis of weight, germination percent and vigour index of seed as an important criterion for delineating the superior seed source. This preliminary investigation will be useful for further improvement of the species for better productivity.
17
Power, Dennis M., and David G. Ainley. "Seabird Geographic Variation: Similarity Among Populations of Leach's Storm-Petrel." Auk 103, no. 3 (July 1, 1986): 575–85. http://dx.doi.org/10.1093/auk/103.3.575.
Повний текст джерелаАнотація:
Abstract We assessed geographic variation in 13 locality samples of Leach's Storm-Petrel (Oceanodroma leucorhoa), 12 from the Pacific coast and 1 from the Atlantic coast of North America. Nine phenetic characters were used with canonical variates analysis to determine similarity among samples. Regression of phenetic distance on geographic distance measured the relation between similarity and interisland distance. We found a clinal pattern of population similarity from the Aleutian Islands in the north to the Farallon Islands in the south. Populations from Los Coronados and San Benitos islands make up a distinct subset when rump color and wing and tail shape indices are included in the analysis, but these populations were part of a dominant clinal trend when only five size characters were used. On Guadalupe Island separate populations breed in summer and winter; these are strongly differentiated from the others and from each other. The North Atlantic sample was aligned closely with that from the Aleutians. The degree of geographic variation was roughly similar to that in certain migratory land birds on the North American continent, but is less than what is found for certain nonmigratory land birds on islands. Our results suggest recognizing four subspecies of Leach's Storm-Petrel in the study area, including two on Guadalupe Island isolated by time of breeding.
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Alexandrino, J., N. Ferrand, J. W. Arntzen, and João Alexandrino. "Morphological variation in two genetically distinct groups of the golden-striped salamander, Chioglossa lusitanica (Amphibia: Urodela)." Contributions to Zoology 74, no. 3-4 (2005): 213–22. http://dx.doi.org/10.1163/18759866-0740304001.
Повний текст джерелаАнотація:
Morphometric and colour pattern variation in the endemic Iberian salamander Chioglossa lusitanica is concordant with the genetic differentiation of two groups of populations separated by the Mondego river in Portugal. Salamanders from the south have shorter digits than those from the north. Clinal variation with a south to north increase in limb, toe and finger length was found superimposed on this dichotomy, resulting in stepped clines for characters describing appendage size. Genetic variability was paralleled by colour pattern variability in the contact zone and in northern populations. To explain the observed parallels we invoke the neutral processes of vicariant isolation, admixture in a secondary contact zone, genetic drift in addition to selection acting along an environmental gradient. Morphological constraints imposed by a highly specialized ecological niche may explain why the genetic subdivision of C. lusitanica since the early Pleistocene has remained fairly cryptic.
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Groh, Jeffrey S., and Quentin C. B. Cronk. "Phenotypic evidence for an extensive mosaic hybrid zone between two species of columbine, Aquilegia flavescens and A. formosa." Botany 98, no. 8 (August 2020): 459–67. http://dx.doi.org/10.1139/cjb-2020-0015.
Повний текст джерелаАнотація:
Describing the structure and dynamics of hybrid zones has important consequences for our understanding of lineage diversification. Herbarium collections constitute an extensive, though often underutilized, morphological resource that can potentially be leveraged to identify and describe hybrid zones. We demonstrate the use of herbarium collections to describe the structure of a hybrid zone between two North American columbines, Aquilegia flavescens S. Watson and A. formosa Fisch. ex DC. Hybrid indices were calculated from floral morphology measurements and mapped using geolocation data, revealing an extensive and consistent pattern of floral intermediacy in several contact zones. Population phenotype samples from contact zones corroborate these findings and strongly suggest introgression. At one locality with a confirmed hybrid population, floral phenotypes show clinal variation in parental-type morphology along an elevational gradient, in the direction predicted by the divergent elevational distributions of these taxa. We argue that these patterns together reflect a habitat-associated mosaic hybrid zone, consistent with divergent ecological selection maintaining the structure of the hybrid zone.
20
Graciá, Eva, Francisco Botella, José Daniel Anadón, Pim Edelaar, D. James Harris, and Andrés Giménez. "Surfing in tortoises? Empirical signs of genetic structuring owing to range expansion." Biology Letters 9, no. 3 (June 23, 2013): 20121091. http://dx.doi.org/10.1098/rsbl.2012.1091.
Повний текст джерелаАнотація:
Much of our current knowledge about the genetic dynamics in range expansions originates from models, simulations and microcosm experiments that need to be corroborated by field data. Here, we report a neutral genetic pattern that matches the predictions of the genetic surfing theory. Genetic surfing occurs when repeated founding events and genetic drift act on the wave of advance of an expanding population, promoting strong spatial structure. In the range expansion of the tortoise Testudo graeca from North Africa to southeastern Spain, we found several genetic signatures consistent with surfing: a decrease of genetic diversity with distance from the initial founder area, clinal patterns in allele frequencies, rare African alleles which have become common at distal sites in the Spanish range, and stronger spatial differentiation in the expanded range than in the original one. Our results provide support for the theory that genetic drift can be an important force in shaping the genetic structure of expanding populations.
21
Rey, O., and J. Turgeon. "Influence of historical events and contemporary estuarine circulation on the genetic structure of the banded killifish (Fundulus diaphanus) in the St. Lawrence River (Quebec, Canada)." Canadian Journal of Zoology 85, no. 8 (August 2007): 891–901. http://dx.doi.org/10.1139/z07-075.
Повний текст джерелаАнотація:
Eight microsatellite markers were used to examine the historical and contemporary factors influencing the distribution of genetic variation within and among populations of Fundulus diaphanus (Lesueur, 1817) in the St. Lawrence River. Our results show that the contemporary hydrodynamics of the river affect levels of diversity and differentiation in this species. Genetic diversity increased towards downstream sites and levelled off at the upstream end of the tidal section, in the vicinity of Lake St-Pierre outlet. Likewise, differentiation and isolation-by-distance were most pronounced in the upstream, strictly fluvial section of the river. Surprisingly, however, we did not detect any significant intershore differentiation in this riparian fish species. Historical influence was also clearly detected and transcended the contemporary pattern, as revealed by an extremely strong isolation-by-distance pattern along the entire river stretch. This pattern likely results from the historical, postglacial secondary contact between two glacial races, as indicated by the clinal variation of constrasting allele size frequency distributions along the river and the significantly greater values of differentiation indices considering mutational information.
22
JAMISON, SIMON, EREZ MAZA, GUY SINAIKO, KARIN TAMAR, ALEX SLAVENKO, and SHAI MEIRI. "To be or not to be tchernovi: a taxonomic revision of the snake genus Micrelaps (Squamata: Serpentes), in Israel." Zootaxa 4881, no. 2 (November 19, 2020): 290–306. http://dx.doi.org/10.11646/zootaxa.4881.2.4.
Повний текст джерелаАнотація:
The enigmatic snake genus Micrelaps has uncertain phylogenetic affinities. The type species of the genus, Micrelaps muelleri, inhabits the Southern Levant. Snakes inhabiting the Jordan River Valley just south of the Sea of Galilee have been described as a new species, Micrelaps tchernovi, based on their distinct colour patterns, despite M. muelleri being well known to be variable in colour-pattern traits. Here we use morphological and molecular data to examine the taxonomic status and phylogenetic affinity of Levantine Micrelaps. We show that all scalation, colour, and pattern-related traits are extremely variable across the range of these snakes. Some morphological features show clinal variation related to temperature and precipitation, and snakes with a ‘tchernovi’ morph are merely at one end of a continuum of morphological variation. Both ‘classical muelleri’ and ‘tchernovi’ morphs occur in syntopy in the Jordan Valley and elsewhere in Israel. Against this background of high morphological variation, neutral genetic markers show almost no differentiation between snakes, no genetic structure is evident across populations, and no differences are to be found between the two putative species. We conclude that Levantine Micrelaps belongs to a single, morphologically variable, and genetically uniform species, Micrelaps muelleri, of which M. tchernovi is a junior synonym.
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Poljak, Igor, Davorin Kajba, Ivan Ljubić, and Marilena Idžojtić. "Morphological variability of leaves of Sorbus domestica L. in Croatia." Acta Societatis Botanicorum Poloniae 84, no. 2 (2015): 249–59. http://dx.doi.org/10.5586/asbp.2015.023.
Повний текст джерелаАнотація:
The paper studies the morphological variability of the service tree populations in the continental and Mediterranean regions of Croatia. The inter- and intra-population variability, as well as eco-geographic population differentiation, was established on the basis of eight measured morphological characteristics of two types of leaflets (lateral and terminal) and two derived ratios, using descriptive and multivariate statistical methods. The conducted research established a high variability of morphological characteristics. In comparison with lateral leaflets, terminal leaflets showed a higher degree of variability for the majority of the studied variables. The differences between the trees within populations, as well as the differences between populations, were confirmed for all studied characteristics. The study also confirmed a trend of population variations according to the eco-geographic principle. Populations from climatically different and geographically distant habitats, in other words from the Mediterranean and the continental region, differed in the majority of studied characteristics. In addition to the established pattern of ecotypical variability between the continental and the Mediterranean regions, the clinal variability with regard to altitude and mean annual temperature was also confirmed. Small, although statistically significant clinal variability with regard to the longitude was recorded for two measured characteristics. The conducted study provided insights into the variability of the service tree populations in Croatia, which is a basis for further research that should be implemented in order to produce guidelines for the breeding and conservation of genetic resources of this rare and endangered noble hardwood species.
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Rounsevell, D., and D. Pemberton. "The status and seasonal occurrence of Leopard Seals, Hydrurga leptonyx, in Tasmanian waters." Australian Mammalogy 17, no. 1 (1994): 97. http://dx.doi.org/10.1071/am94010.
Повний текст джерелаАнотація:
Seventy nine sightings of Leopard Seals, Hydrurga leptonyx, made over a period of 7 years in Tasmania are reported. They show that the species occurs annually in Tasmanian waters between July and November, probably as a result of northward movement from the Antarctic pack ice zone. Its seasonal occurrence in Tasmanian waters implies that it is a regular member of the marine fauna of the region. This is in contrast to previous reports that the species was a rare vagrant, occasionally stranding along the coastline. Comparisons of the age structure of H. leptonyx in Tasmania with those on subantarctic islands suggests that there is a clinal variation with latitude in the dispersal pattern, as young animals disperse further north than adults.
25
Hand, S., and A. York. "Morphological Variation in the Dentition and Skull of the Australian Ghost Bat, Macroderma-Gigas (Microchiroptera, Megadermatidae)." Australian Journal of Zoology 38, no. 3 (1990): 263. http://dx.doi.org/10.1071/zo9900263.
Повний текст джерелаАнотація:
Morphological variation in the dentition and some cranial characters of the Australian ghost bat, Macroderma gigas, is reviewed by means of univariate and multivariate analyses. Specimens examined are drawn from existing populations across northern Australia; also included for parts of this study are mummified remains from southern central South Australia and late Pleistocene subfossil specimens from south-western Western Australia. No clear-cut geographic pattern in morphological variation in M. gigas is indicated by multivariate anlysis (i.e. principal components analysis), although there is some evidence for clinal variation from univariate analysis (i.e. Scheffe's multiple-comparions procedure). Northern Australian ghost bats (with the exception of north-eastern Australian indiv~duals) tend to be smaller than their southern counterparts. Sexual dimorphism appears to be low. Independent patterns of covariation among characters are extracted by principal components analysis: cheek tooth widths cluster separately from lengths; lengths and widths of the same teeth cluster separately from those of occluding teeth; and cranial measurements cluster separately from tooth measurements. Patterns in the data suggest that the number of characters needed to be examined in future morphometric studies of the vulnerable ghost bat can be significantly reduced.
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Gailing, Oliver, and C. Dana Nelson. "Genetic variation patterns of American chestnut populations at EST-SSRs." Botany 95, no. 8 (August 2017): 799–807. http://dx.doi.org/10.1139/cjb-2016-0323.
Повний текст джерелаАнотація:
The objective of this study is to analyze patterns of genetic variation at genic expressed sequence tag – simple sequence repeats (EST-SSRs) and at chloroplast DNA markers in populations of American chestnut (Castanea dentata Borkh.) to assist in conservation and breeding efforts. Allelic diversity at EST-SSRs decreased significantly from southwest to northeast along the Appalachian range, suggesting repeated founder events during postglacial migration. Comparatively high allelic diversity in Ontario, northwest of the Appalachian range, suggested more recent long-distance dispersal. Clinal variation of allele frequencies along the Appalachian axis was also in accordance with postglacial colonization from one refugium southwest of the Appalachian range. We observed clustering of the northwestern population from Ontario with southwestern populations and sharing of a rare chloroplast haplotype among western populations across the whole latitudinal range. This pattern is consistent with a divergence of postglacial migration routes and higher levels of more recent potentially human-mediated gene exchange between populations west of the Appalachian range. Population pairs east and west of the Appalachian axis showed pronounced allele frequency differences over a small geographic range. These patterns of genetic variation should be considered when sampling reproductive material for conservation and breeding.
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Houle, Gilles. "Environmental filters and seedling recruitment on a coastal dune in subarctic Quebec (Canada)." Canadian Journal of Botany 74, no. 9 (September 1, 1996): 1507–13. http://dx.doi.org/10.1139/b96-181.
Повний текст джерелаАнотація:
One important factor that often determines the presence of a plant species on a site is propagule availability. Afterwards, abiotic and biotic factors act as a series of filters operating sequentially from the seed to the adult stage, determining the pattern of recruitment. By comparing the spatial pattern of emerging seedlings to those of seed availability and of surviving seedlings, one can determine the relative importance of the environmental filters acting on the seed germination and the seedling establishment phases. On a coastal dune system in subarctic Quebec (Canada), sand accumulation, salt spray, and substrate physicochemistry, all affecting microsite quality for seeds and seedlings, vary along a short topographical gradient. My goal was to determine whether or not conditions changing along this gradient differentially affect the initial stages of population recruitment of two perennial herbaceous species for which adults are segregated along the gradient: Honckenya peploides and Elymus mollis. The spatial pattern of seeds in the seed bank and that of emerging seedlings were not related to one another for either Honckenya or Elymus. However, patterns of surviving seedlings were spatially correlated with those of emerging seedlings. Seed and seedling mortality were not density dependent; they were both spatially variable, although not clinal. These results suggest that the environmental filters acting on the germination stage are those that determine the spatial patterns of recruitment. Spatial segregation along the flank of the foredune between adults of the two species studied thus seems to be maintained in part (and maybe reinforced) by low seed mobility, or low seed retention, and the availability of suitable microsites for seed germination. Population progression towards the upper beach seems to depend mostly on seedling establishment for Honckenya but on clonal growth for Elymus. Keywords: Elymus mollis, Honckenya peploides, Hudson Bay, partial Mantel test, spatial segregation, Whapmagoostui-Kuujjuaraapik.
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Tavares, Hugo, Annabel Whibley, David L. Field, Desmond Bradley, Matthew Couchman, Lucy Copsey, Joane Elleouet, et al. "Selection and gene flow shape genomic islands that control floral guides." Proceedings of the National Academy of Sciences 115, no. 43 (October 8, 2018): 11006–11. http://dx.doi.org/10.1073/pnas.1801832115.
Повний текст джерелаАнотація:
Genomes of closely-related species or populations often display localized regions of enhanced relative sequence divergence, termed genomic islands. It has been proposed that these islands arise through selective sweeps and/or barriers to gene flow. Here, we genetically dissect a genomic island that controls flower color pattern differences between two subspecies of Antirrhinum majus, A.m.striatum and A.m.pseudomajus, and relate it to clinal variation across a natural hybrid zone. We show that selective sweeps likely raised relative divergence at two tightly-linked MYB-like transcription factors, leading to distinct flower patterns in the two subspecies. The two patterns provide alternate floral guides and create a strong barrier to gene flow where populations come into contact. This barrier affects the selected flower color genes and tightly-linked loci, but does not extend outside of this domain, allowing gene flow to lower relative divergence for the rest of the chromosome. Thus, both selective sweeps and barriers to gene flow play a role in shaping genomic islands: sweeps cause elevation in relative divergence, while heterogeneous gene flow flattens the surrounding “sea,” making the island of divergence stand out. By showing how selective sweeps establish alternative adaptive phenotypes that lead to barriers to gene flow, our study sheds light on possible mechanisms leading to reproductive isolation and speciation.
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Pitocchelli, J. "Macrogeographic variation in the song of the Mourning Warbler (Oporornis philadelphia)." Canadian Journal of Zoology 89, no. 11 (November 2011): 1027–40. http://dx.doi.org/10.1139/z11-077.
Повний текст джерелаАнотація:
Studies of macrogeographic variation in birdsong involve populations incapable of interbreeding because of physical barriers or separation by large distances. Different patterns have emerged from these studies such as (i) little or no variation exists among individuals or populations from the breeding range, (ii) individual variation is greater than among population variation resulting in no geographic structure, (iii) clinal variation, and (iv) macrogeographic variation where all individuals from several populations on the breeding range share a common song type forming a regional dialect or regiolect. I studied macrogeographic variation in song of the Mourning Warbler ( Oporornis philadelphia (A. Wilson, 1810)). The observed pattern was similar to the fourth category of geographic variation with regiolects. A Western regiolect extended from northern Alberta to western Ontario. An Eastern regiolect stretched eastward from western Ontario and Wisconsin to the Gaspé Peninsula and New England, then southward through the Appalachians to West Virginia. Nova Scotia and Newfoundland each had unique regiolects. Finally, I compared these results to other species with regiolects and assessed the ability of some deterministic hypotheses to explain song divergence (e.g., role of morphology, physical barriers, island isolation).
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Heinze, D. M., E. A. Gould, and N. L. Forrester. "Revisiting the Clinal Concept of Evolution and Dispersal for the Tick-Borne Flaviviruses by Using Phylogenetic and Biogeographic Analyses." Journal of Virology 86, no. 16 (June 6, 2012): 8663–71. http://dx.doi.org/10.1128/jvi.01013-12.
Повний текст джерелаАнотація:
Tick-borne flaviviruses (TBF) are widely dispersed across Africa, Europe, Asia, Oceania, and North America, and some present a significant threat to human health. Seminal studies on tick-borne encephalitis viruses (TBEV), based on partial envelope gene sequences, predicted a westward clinal pattern of evolution and dispersal across northern Eurasia, terminating in the British Isles. We tested this hypothesis using all available full-length open reading frame (ORF) TBF sequences. Phylogenetic analysis was consistent with current reports. However, linear and nonlinear regression analysis of genetic versus geographic distance combined with BEAST analysis identified two separate clines, suggesting that TBEV spread both east and west from a central point. In addition, BEAST analysis suggested that TBF emerged and dispersed more than 16,000 years ago, significantly earlier than previously predicted. Thus, climatic and ecological changes may have played a greater role in TBF dispersal than humans.
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BALANT, MANICA, PETER GLASNOVIĆ, ŽIVA FIŠER PEČNIKAR, MORENO CLEMENTI, and BOŠTJAN SURINA. "In search of an identity for Salvia bertolonii (Lamiaceae)." Phytotaxa 413, no. 2 (July 31, 2019): 117–36. http://dx.doi.org/10.11646/phytotaxa.413.2.2.
Повний текст джерелаАнотація:
Classical and geometric morphometric analyses of floral characters of Salvia pratensis agg. were performed on populations from the E Adriatic area. Both types of analyses yielded congruent results, and three groups of populations, attributed to S. verbenaca, which served as an outgroup, S. saccardiana and S. pratensis (incl. S. bertolonii), were unambiguously identified. Results confirmed floral size dimorphism, with hermaphroditic flowers being significantly bigger than female ones, while we newly identified floral shape dimorphism in S. pratensis, too. No gynodioecious populations were observed in morphologically otherwise very uniform S. saccardiana. Being a SE Alpine endemic, the latter was for the first time recorded in Croatia. While S. saccardiana merits species rank, we found no support for the segregation of S. bertolonii and S. pratensis. Clinal variation in floral characters of S. pratensis, generally detected in populations of various taxa along the E Adriatic coast, lacks the spatial consistency and geographic pattern that would allow for a clear delimitation of S. pratensis and S. bertolonii.
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DAPPORTO, LEONARDO, and FRANCO STRUMIA. "The thorny subject of insular endemic taxonomy: morphometrics reveal no evidence of speciation between Coenonympha corinna and Coenonympha elbana butterflies (Lepidoptera: Nymphalidae)." Zootaxa 1755, no. 1 (April 24, 2008): 47. http://dx.doi.org/10.11646/zootaxa.1755.1.3.
Повний текст джерелаАнотація:
Species demarcation between mainland and island endemic populations is often subjective according to the biological concept of species. However, the recognition of the specific status of island endemics is decisive for biogeography and conservation studies. In this paper we applied rigorous morphometric analyses instead of subjective visual evaluation to solve the long debated question whether the endemic butterfly from Tuscany Coenonympha elbana should be considered as a separated entity from the endemic C. corinna from Sardinia and Corsica. We carried out traditional and geometric morphometric analyses of wing pattern and male genitalia comparing the populations from Corsica, Sardinia, Tuscan Archipelago and Tuscany. We found that Sardo-Corsican C. corinna and Tuscan C. elbana can be distinguished only on the basis of the dimension of ventral wing ocelli. However, this characteristic shows a clinal pattern from Sardinia to Tuscany. Moreover, there is not any clear diversification in the shape of male genitalia between the two entities and each islet population can not be unambiguously attributed to one of the two taxa. In conclusion, we found no decisive evidence for a specific diversification between these two entities and the Coenonympha corinna/elbana complex, occurring both in Sardinia-Corsica and in the Italian mainland, should not be strictly considered as an endemic insular taxa.
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Henriques, Dora, Julio Chávez-Galarza, Juliana S. G. Teixeira, Helena Ferreira, Cátia J. Neves, Tiago M. Francoy, and M. Alice Pinto. "Wing Geometric Morphometrics of Workers and Drones and Single Nucleotide Polymorphisms Provide Similar Genetic Structure in the Iberian Honey Bee (Apis mellifera iberiensis)." Insects 11, no. 2 (January 30, 2020): 89. http://dx.doi.org/10.3390/insects11020089.
Повний текст джерелаАнотація:
Wing geometric morphometrics has been applied to honey bees (Apis mellifera) in identification of evolutionary lineages or subspecies and, to a lesser extent, in assessing genetic structure within subspecies. Due to bias in the production of sterile females (workers) in a colony, most studies have used workers leaving the males (drones) as a neglected group. However, considering their importance as reproductive individuals, the use of drones should be incorporated in these analyses in order to better understand diversity patterns and underlying evolutionary processes. Here, we assessed the usefulness of drone wings, as well as the power of wing geometric morphometrics, in capturing the signature of complex evolutionary processes by examining wing shape data, integrated with geographical information, from 711 colonies sampled across the entire distributional range of Apis mellifera iberiensis in Iberia. We compared the genetic patterns reconstructed from spatially-explicit shape variation extracted from wings of both sexes with that previously reported using 383 genome-wide SNPs (single nucleotide polymorphisms). Our results indicate that the spatial structure retrieved from wings of drones and workers was similar (r = 0.93) and congruent with that inferred from SNPs (r = 0.90 for drones; r = 0.87 for workers), corroborating the clinal pattern that has been described for A. m. iberiensis using other genetic markers. In addition to showing that drone wings carry valuable genetic information, this study highlights the capability of wing geometric morphometrics in capturing complex genetic patterns, offering a reliable and low-cost alternative for preliminary estimation of population structure.
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Riquet, Florentine, Cathy Liautard‐Haag, Lucy Woodall, Carmen Bouza, Patrick Louisy, Bojan Hamer, Francisco Otero‐Ferrer, et al. "Parallel pattern of differentiation at a genomic island shared between clinal and mosaic hybrid zones in a complex of cryptic seahorse lineages." Evolution 73, no. 4 (March 11, 2019): 817–35. http://dx.doi.org/10.1111/evo.13696.
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LOPES, LEONARDO ESTEVES, and LUIZ PEDREIRA GONZAGA. "Clinal pattern of morphological variation in Sakesphorus luctuosus (Lichtenstein, 1823), with comments on the enigmatic Sakesphorus hagmanni Miranda-Ribeiro, 1927 (Passeriformes: Thamnophilidae)." Zootaxa 3569, no. 1 (November 30, 2012): 41. http://dx.doi.org/10.11646/zootaxa.3569.1.3.
Повний текст джерелаАнотація:
Sakesphorus luctuosus (Glossy Antshrike) is endemic to Brazil, harboring two subspecies. The nominal subspecies is widespread in the Amazon region, and S. l. araguayae is endemic to the Rio Araguaia valley. In this paper we investigated the hypothesis that S. l. araguayae represents the end of a cline. We examined 588 specimens housed in Brazilian, North American and European museums and based our conclusions on plumage coloration and morphometric characters. We found no significant differences in morphometric characters between subspecies, except for culmen length, which was slightly shorter in S. l. araguayae, but with wide overlap in measurements. The main proposed diagnostic character between subspecies (length of the white tips to tail feathers) showed clinal variation, with northern birds showing more white on the tail, and southern birds showing less white on the tail, irrespective of hydrographic basin. The other diagnostic character proposed (width of the white edges to the outer webs of the scapular feathers) showed high individual variation and no taxonomic consistency. We conclude that S. l. araguayae is a junior synonym of the nominal taxon. On the other hand, S. hagmanni, known only from the holotype and long thought to be a junior synonym of the nominal taxon, proved to be a unique specimen that should be considered as species inquirenda until further investigations determine its status.
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ANDREANI, TAINÃ LUCAS, SEIXAS REZENDE OLIVEIRA, VINÍCIUS GUERRA, ROGÉRIO PEREIRA BASTOS, and ALESSANDRO RIBEIRO DE MORAIS. "The aggressive call of Dendropsophus cruzi (Pombal & Bastos, 1998) (Anura; Hylidae) in Central Brazil." Zootaxa 4379, no. 1 (February 13, 2018): 137. http://dx.doi.org/10.11646/zootaxa.4379.1.9.
Повний текст джерелаАнотація:
Dendropsophus cruzi (Pombal & Bastos, 1998) is a small hylid (male snout-to-vent length = 16.3–19.4 mm; female SVL = 21.3–25.0 mm) that is allocated in the D. microcephalus group (Faivovich et al. 2005). It is commonly found in Open and forested areas from Central Brazil to Provincia Velasco, Departamento de Santa Cruz, Bolivia (Frost 2017; Tessarolo et al. 2016). Pombal & Bastos (1998) described the advertisement call of D. cruzi as a single pulsed note. Posteriorly, studies uncovered relationships between dominant frequency variation in the advertisement calls of D. cruzi and variation in the SVL and mass of males (Bastos et al. 2003), as well as the existence of a clinal geographic pattern in the variation of acoustic parameters of these calls (Tessarolo et al. 2016). However, the acoustic communication in anurans is usually mediated by more than one vocalization type (Toledo et al. 2015). Due the importance of call types in the social context of anurans (e.g., Reichert 2011; Forti et al. 2017), we expand the vocal repertoire of D. cruzi by describing its aggressive call.
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Rogers, D. L., R. F. Stettler, and P. E. Heilmann. "Genetic variation and productivity of Populustrichocarpa and its hybrids. III. Structure and pattern of variation in a 3-year field test." Canadian Journal of Forest Research 19, no. 3 (March 1, 1989): 372–77. http://dx.doi.org/10.1139/x89-056.
Повний текст джерелаАнотація:
Growth and morphology of 308 black cottonwood (Populustrichocarpa Torr & Gray) clones were studied at one plantation site in northwestern Washington. The material was derived from both open-pollinated seed and branch cuttings from 10 natural populations in major river valleys west of the Cascade Range, between central Oregon (latitude 44°44′) and southern British Columbia (latitude 49°05′). Most of the clones (258) were derived from open-pollinated seedlings, with approximately six from each of two to five selected parents per population. Fifty of the clones were ramets from five field-selected ortets per population. Each clone was represented by two ramets in each of two blocks in a randomized complete block design. Three-year height and diameter growth displayed the largest amount of variation at the clonal level, followed by lesser amounts at the family and population levels. A significant block × clone interaction, combined with some responses contrasting with earlier studies on a different site, suggests that the interaction of genotype with environment is important for this species. Weak clinal trends were observed, despite a large degree of within-population variation. Narrow-sense heritability estimates and their standard errors were 0.10 ± 0.08 and 0.13 ± 0.09 for 3rd-year height and diameter, respectively. Significant trait correlations were obtained between volume and branch characteristics. The implications of these results and their relationship to other ongoing work in black cottonwood are discussed.
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Duarte-Neto, Paulo, Rosângela Lessa, Borko Stosic, and Eric Morize. "The use of sagittal otoliths in discriminating stocks of common dolphinfish (Coryphaena hippurus) off northeastern Brazil using multishape descriptors." ICES Journal of Marine Science 65, no. 7 (June 3, 2008): 1144–52. http://dx.doi.org/10.1093/icesjms/fsn090.
Повний текст джерелаАнотація:
Abstract Duarte-Neto, P., Lessa, R., Stosic, B., and Morize, E. 2008. The use of sagittal otoliths in discriminating stocks of common dolphinfish (Coryphaena hippurus) off northeastern Brazil using multishape descriptors. – ICES Journal of Marine Science, 65: 1144–1152. The shape of sagittal otoliths from the dolphinfish (Coryphaena hippurus) was studied to test the hypothesis that two stocks exist off the northeast coast of Brazil. In all, 82 sagittal otoliths were collected from fish caught by the artisanal fleet in two coastal regions of northeastern Brazil in December 2003 and April/May 2004. Several shape descriptors were determined [area, perimeter, rectangularity, circularity, eccentricity, fractal dimension (FD), and Fourier coefficients (FCs)] to evaluate the degree of similarity in the otoliths between regions. A three-morphotype pattern was revealed through cluster and principal component analyses based on FCs of the 30th harmonics. Apparently, this pattern is not influenced by clinal factors. Despite the great variability between otolith shapes, separation of the samples from two regions was suggested using multivariate and univariate analyses of variance for all shape descriptors and using canonical discriminant analysis. The methods successfully classified 57.1 and 69.6% of otoliths from the Maranhão and Rio Grande do Norte regions, respectively. The FD was a powerful descriptor in discriminating the two stocks. Differences in the shapes of sagittal otoliths may be related to different growth rates of the species and lend credence to the belief that there are two stocks along the Brazilian coast.
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Claytor, Ross R., and Hugh R. MacCrimmon. "Morphometric and meristic variability among North American Atlantic salmon (Salmo salar)." Canadian Journal of Zoology 66, no. 2 (February 1, 1988): 310–17. http://dx.doi.org/10.1139/z88-046.
Повний текст джерелаАнотація:
To investigate the morphometric and meristic variation of Atlantic salmon (Salmo salar) in North America, juveniles from 16 anadromous and 5 nonanadromous populations were collected from an area extending from Labrador to New York state. The findings from the analysis of these characters were supplemented by an examination of malate dehydrogenase variation on a subset of specimens from selected populations. Newfoundland – Labrador and Gaspé – Maritime populations were found to belong to distinct regional stocks. This conclusion was supported by the accuracy of the morphometric discriminant function and a discontinuity in Mdh-3,4(100) allele frequencies. The lack of a clinal relationship between morphometric characters, latitude, longitude, and number of degree-days above 7 °C also suggested a pattern of distinct regional stocks. Considerable overlap among populations was found for meristic characteristics, and these were considered unsuitable for stock identification purposes. While no somatic differences were found between anadromous and nonanadromous populations, there were significant differences in Mdh-3,4(100) frequencies. The congruence of morphometric and malate dehydrogenase characteristics in delineating regional stocks emphasizes the importance of a multiple character approach in solving stock identification problems.
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KRIST, A. C., C. M. LIVELY, E. P. LEVRI, and J. JOKELA. "Spatial variation in susceptibility to infection in a snail–trematode interaction." Parasitology 121, no. 4 (October 2000): 395–401. http://dx.doi.org/10.1017/s0031182099006538.
Повний текст джерелаАнотація:
Parasites should be better at infecting hosts from sympatric populations than allopatric populations most of the time (parasite local adaptation). In a previous study of a population of snail parasites (Microphallus sp.) from Lake Alexandrina, New Zealand, we found that Microphallus was more infective to snails (Potamopyrgus antipodarum) in shallow water but not in deep water. Here, we repeated the original study and also monitored the development of the parasite. We found that parasites from shallow water were more infective to hosts from shallow water and developed more rapidly in these hosts. In contrast, parasites from deep water were not more infective to hosts from deep water and did not develop more rapidly in them. These results suggest clinal variation in the susceptibility of these snails, with shallow-water snails more susceptible than deep-water snails. We offer 2 possible explanations for these results. First, gene flow in the Microphallus population is primarily from shallow to deep water, leading to an asymmetric pattern of local adaptation. Alternatively, snails from shallow water may be more susceptible for reasons independent of gene flow, perhaps due to differences in host condition between habitats.
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Sung, Ha-Cheol, and Paul Handford. "Songs of the Savannah Sparrow: structure and geographic variation." Canadian Journal of Zoology 84, no. 11 (November 2006): 1637–46. http://dx.doi.org/10.1139/z06-159.
Повний текст джерелаАнотація:
We investigated song structure and the pattern of geographic variation at the syllable and whole song levels in Savannah Sparrow, Passerculus sandwichensis (J.F. Gmelin, 1789). Songs were recorded for 179 males from eight sample populations distributed along a 230 km transect in southwestern Ontario in 2000. Subsequent analysis included measurement and comparison of structural song features and qualitative analysis of syllable and song type similarity among individuals both within and among populations, by reference to a syllable catalogue based on syllable similarity. Song type sharing within samples was not common, while song dissimilarity significantly correlated with distance among samples. Overall south–north trends appeared in two aspects of quantitative and qualitative characteristics, and the geographic differentiation of Savannah Sparrow songs was gradual, increasing with distance. At a higher level of analysis, two song groups, with qualitatively distinct structures (here termed themes), were identified. These themes showed a clinal intergrade, such that one theme was found in all individuals of the four southern samples, while in the four more northerly samples, the second theme's incidence grew progressively from 20% to 80%. However, birds singing the southern theme in populations dominated by the northern theme nevertheless produced songs that show metrical (frequency and duration) characteristics typical of the northern theme songs from their own population. Cluster analysis based on syllable and song type similarity–dissimilarity between populations linked geographically neighboring populations closely, while populations fell into two main clusters: the three most northerly and the five most southerly populations. The same cluster pattern also appeared within each theme type.
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Silva, Inês C., Stephen J. Hawkins, and José Paula. "A comparison of population differentiation in two shore crab species with contrasting distribution along the Portuguese coast, using two morphological methodologies." Marine and Freshwater Research 60, no. 8 (2009): 833. http://dx.doi.org/10.1071/mf08215.
Повний текст джерелаАнотація:
Along the Portuguese coast, Pachygrapsus marmoratus has a continuous distribution on rocky shores. In contrast, Carcinus maenas has a discontinuous distribution, inhabiting estuaries. Surveys along a coastal latitudinal gradient were made to assess the effect of the distribution pattern on population differentiation of these two species. Population differentiation was studied using two different morphometric methodologies: linear-based morphometrics and landmark-based morphometrics. The linear-based analysis revealed no significant morphological differentiation among the eleven P. marmoratus populations. Landmark-based analysis showed that the northern and central populations were more similar in shape than the southern populations. Nevertheless, there was still some overlap in shape that could be due to the continuous distribution of P. marmoratus along the coast, promoting population panmixia. In C. maenas, both morphometric techniques revealed the existence of morphological differentiation among populations. This shape differentiation showed a clinal variation, explained by a higher degree of isolation of populations that might be due to limited larval flow between them. Environmental factors may also play an important role in causing variation of shape. Landmark-based morphometrics yielded stronger evidence of morphological differences among forms than a linear approach, suggesting that this method may be more suitable for analysis of body shape.
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Tapisso, Joaquim T., Sofia I. Gabriel, Ana Mota Cerveira, Janice Britton-Davidian, Guila Ganem, Jeremy B. Searle, Maria da Graça Ramalhinho, and Maria da Luz Mathias. "Spatial and Temporal Dynamics of Contact Zones Between Chromosomal Races of House Mice, Mus musculus domesticus, on Madeira Island." Genes 11, no. 7 (July 6, 2020): 748. http://dx.doi.org/10.3390/genes11070748.
Повний текст джерелаАнотація:
Analysis of contact zones between parapatric chromosomal races can help our understanding of chromosomal divergence and its influence on the speciation process. Monitoring the position and any movement of contact zones can allow particular insights. This study investigates the present (2012–2014) and past (1998–2002) distribution of two parapatric house mouse chromosomal races—PEDC (Estreito da Calheta) and PADC (Achadas da Cruz)—on Madeira Island, aiming to identify changes in the location and width of their contact. We also extended the 1998–2002 sampling area into the range of another chromosomal race—PLDB (Lugar de Baixo). Clinal analysis indicates no major geographic alterations in the distribution and chromosomal characteristics of the PEDC and PADC races but exhibited a significant shift in position of the Rb (7.15) fusion, resulting in the narrowing of the contact zone over a 10+ year period. We discuss how this long-lasting contact zone highlights the role of landscape on mouse movements, in turn influencing the chromosomal characteristics of populations. The expansion of the sampling area revealed new chromosomal features in the north and a new contact zone in the southern range involving the PEDC and PLDB races. We discuss how different interacting mechanisms (landscape resistance, behaviour, chromosomal incompatibilities, meiotic drive) may help to explain the pattern of chromosomal variation at these contacts between chromosomal races.
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Bednorz, Leszek. "Morphological variability of leaves of Sorbus torminalis (L.) Crantz in Poland." Acta Societatis Botanicorum Poloniae 75, no. 3 (2011): 233–43. http://dx.doi.org/10.5586/asbp.2006.028.
Повний текст джерелаАнотація:
This paper presents the results of the study on morphological variability of leaves of a scattered tree species <em>Sorbus torminalis</em> (L.) Crantz) in Poland. The leaves from short- and long shoots were collected from 17 localities widespread within the range of the species in Poland. Leaves were measured according to 15 morphological traits. The biometric data were subjected to multivariate statistical analysis in attempt to define variability between local populations. Most of the leaf traits are significantly correlated and are characterised by moderate level of variation. The average among population component of variation was 32.82% and 27.46% for leaves on short- and long shoots, respectively. The differences between sampled populations are significant, but only a weak geographical pattern of this differentiation was detected. Clinal type of variation was ascertained in two traits. Leaf traits which discriminate best the studied populations are also indicated. It was proved that leaves on short shoots differ markedly in shape and size from those of long shoots. Leaves on long shoots are steadier, but morphological trait values are less correlated. The study also confirmed the occurrence of individuals with leaves characteristic for <em>S. torminalis</em> var. perincisa Borbas et Feck and <em>S. torminalis</em> f. <em>mollis</em> Beck in a few Polish populations.
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Boussy, I. A., M. J. Healy, J. G. Oakeshott, and M. G. Kidwell. "Molecular analysis of the P-M gonadal dysgenesis cline in eastern Australian Drosophila melanogaster." Genetics 119, no. 4 (August 1, 1988): 889–902. http://dx.doi.org/10.1093/genetics/119.4.889.
Повний текст джерелаАнотація:
Abstract The latitudinal cline in P-M gonadal dysgenesis potential in eastern Australia has been shown to comprise three regions which are, from north to south respectively, P, Q, and M, with the P-to-Q and Q-to-M transitions occurring over relatively short distances. The P element complements of 30 lines from different regions of the cline were determined by molecular techniques. The total amount of P element-hybridizing DNA was high in all lines, and it did not correlate in any obvious way with the P-M phenotypes of individual lines. The number of potentially full-sized P elements per genome was high in lines from the P regions, but variable or low among lines from the Q and M regions, and thus declined overall from north to south. A particular P element deletion-derivative, the KP element, occurred in all the tested lines. The number of KP elements was low in lines from the P region, much higher in lines from the Q region, and highest among lines from the M region, thus forming a cline reciprocal to that of the full-sized P elements. Another transposable element, hobo, which has been described as causing dysgenic traits similar to those of P-M hybrid dysgenesis, was shown to be present in all lines and to vary among them in number, but not in any latitudinal pattern. The P-M cline in gonadal dysgenesis potential can be inferred to be based on underlying clinal patterns of genomic P element complements. P activity of a line was positively correlated with the number of full-sized P elements in the line, and negatively correlated with the number of KP elements. Among Q and M lines, regulatory ability was not correlated with numbers of KP elements.
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Chardine, John W. "Geographic Variation in the Wingtip Patterns of Black-Legged Kittiwakes." Condor 104, no. 3 (August 1, 2002): 687–93. http://dx.doi.org/10.1093/condor/104.3.687.
Повний текст джерелаАнотація:
Abstract This paper reports geographic variation in wingtip patterns of Black-legged Kittiwakes (Rissa tridactyla) from the circumpolar Arctic. The amount of black in the wingtip increased and the amount of white decreased from Arctic Canada–west Greenland, counterclockwise to the Pacific. Differences were greatest between Pacific and Atlantic, but were also apparent within the Atlantic sample. Patterns of variation were not clinal. Known levels of philopatry in kittiwakes would tend to maintain both phenotypic and genotypic differences between regions, but the similarity of birds from Newfoundland, British Isles, and Barents Sea suggests some degree of dispersal over this wide area. Wingtip pattern data support continued separation of Pacific and Atlantic kittiwakes into two subspecies under the biological species concept. Under the phylogenetic species concept, Pacific and Atlantic Black-legged Kittiwakes may represent two species. Variación Geográfica en los Patrones de Coloración de la Punta del Ala de Rissa tridactyla Resumen. Este trabajo presenta la variación geográfica existente en los patrones de coloración de la punta del ala de Rissa tridactyla en el área circumpolar ártica. La cantidad de negro en la punta del ala incrementó y la cantidad de blanco disminuyó desde el ártico canadiense y el oeste de Groenlandia en sentido contrario a las agujas del reloj hacia el Pacífico. Las mayores diferencias se registraron entre el Pacífico y el Atlántico, pero también fueron evidentes en la muestra del Atlántico. Los patrones de variación no fueron graduales. Los niveles conocidos de filopatría en R. tridactyla tenderían a mantener las diferencias tanto fenotípicas como genotípicas entre regiones, pero la similitud de las aves de Newfoundland, las Islas Británicas y el Mar de Barents sugiere algún grado de dispersión a través de esta extensa área. Considerando el concepto biológico de especie, los datos sobre los patrones de la punta del ala apoyan la separación de las aves del Pacífico y del Atlántico en dos subespecies. Considerando el concepto filogenético de especie, los individuos de R. tridactyla del Pacífico y del Atlántico pueden pertenecer a dos especies diferentes.
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Kramarenko, A. S., Zh V. Ignatenko, and O. I. Yulevich. "Intrapopulation variation in shell morphological traits and banding polymorphism of the land snail Cepaea vindobonensis (Gastropoda; Pulmonata; Helicidae)." Ukrainian Journal of Ecology 10, no. 5 (October 20, 2020): 114–21. http://dx.doi.org/10.15421/2020_215.
Повний текст джерелаАнотація:
The main goal of this paper was to analyze intrapopulation variation of both morphological traits and shell banding polymorphism using the example of a continuous population (a metapopulation) of the land snail Cepaea vindobonensis (Férussac, 1821). A total of 14 samples of the land snail C. vindobonensis from a population located in the “Dubki” Park (Ukraine, Mykolayiv) were collected in May-July 2007. The land snail collection sites are divided into three areas by buildings and asphalt roads, indicated by the Latin letters A, B and C. The major diameter of shell (MJD), the minor diameter of shell (MID) and the shell height (SH) were measured with a digital calliper to the nearest 0.05 mm. Two shell shape indices (SF1 and SF2) were also computed. A high level of the intrapopulation variation of the land snail C. vindobonensis was found in our study. Significant differences between sample means were found for all shell traits and indices used (except for SF1), however, maximum difference was noted for SH and SF2 (in both cases: P ≤ 0.001). About 80% of the total variation of the variance-covariance matrix was explained by the 1st and 2nd Principal Components (PC1 and PC2). The PC1 was characterized by high positive factor loadings of MJD, MID and SH and thus can be interpreted as “shell size dimension” and the PC2 had a high correlation with SF2 and thus it can be interpreted as “shell globularity”. The PC1 and PC2 determined a high level of spatial differentiation of intrapopulation morphological variation of the land snail C. vindobonensis. Samples with small (area A) and large (areas B and C) shells were separated from each other according to the PC1. Areas B and C were characterized by individuals with flatness and globularity shells, respectively. The areas A, B and C differed significantly in the total number of morphs, average number of morphs and frequency of rare morphs (Kruskal-Wallis H-test; in all cases P ≤ 0.010). At the same time, the highest value of phenetic diversity was noted for samples collected within A and C areas. In general all phenetic diversity estimators showed a positive correlation with sample size (Spearman's correlation coefficient; in all cases P ≤ 0.05). It was found that the type of biotope did not likely affect the frequency of individual morphs with respect to the shell banding polymorphism pattern. With regard to the most common morphs two patterns of the spatial arrangement of the intrapopulation variation were found – clinal pattern was for the frequency of pallescens morph and chaotic pattern was for frequency of “12345” morph.
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Stock, Amanda J., Brandon E. Campitelli, and John R. Stinchcombe. "Quantitative genetic variance and multivariate clines in the Ivyleaf morning glory, Ipomoea hederacea." Philosophical Transactions of the Royal Society B: Biological Sciences 369, no. 1649 (August 19, 2014): 20130259. http://dx.doi.org/10.1098/rstb.2013.0259.
Повний текст джерелаАнотація:
Clinal variation is commonly interpreted as evidence of adaptive differentiation, although clines can also be produced by stochastic forces. Understanding whether clines are adaptive therefore requires comparing clinal variation to background patterns of genetic differentiation at presumably neutral markers. Although this approach has frequently been applied to single traits at a time, we have comparatively fewer examples of how multiple correlated traits vary clinally. Here, we characterize multivariate clines in the Ivyleaf morning glory, examining how suites of traits vary with latitude, with the goal of testing for divergence in trait means that would indicate past evolutionary responses. We couple this with analysis of genetic variance in clinally varying traits in 20 populations to test whether past evolutionary responses have depleted genetic variance, or whether genetic variance declines approaching the range margin. We find evidence of clinal differentiation in five quantitative traits, with little evidence of isolation by distance at neutral loci that would suggest non-adaptive or stochastic mechanisms. Within and across populations, the traits that contribute most to population differentiation and clinal trends in the multivariate phenotype are genetically variable as well, suggesting that a lack of genetic variance will not cause absolute evolutionary constraints. Our data are broadly consistent theoretical predictions of polygenic clines in response to shallow environmental gradients. Ecologically, our results are consistent with past findings of natural selection on flowering phenology, presumably due to season-length variation across the range.
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Stocker, Ann Jacob, Brad Foley, and Ary Hoffmann. "Inversion frequencies in Drosophila serrata along an eastern Australian transect." Genome 47, no. 6 (December 1, 2004): 1144–53. http://dx.doi.org/10.1139/g04-078.
Повний текст джерелаАнотація:
Clinal patterns over broad geographic regions provide a way of identifying characteristics of species under selection and are increasingly being used in quantitative trait locus mapping of adaptive genetic variation in Drosophila. However, interpretations of clinal patterns can be complicated by inversions that also vary clinally and reduce recombination in some parts of the genome. Drosophila serrata (Malloch) is an Australian endemic species being used to investigate the genetic basis of geographic variation in climatic adaptation and mate recognition. Here we describe inversions in D. serrata populations from the east coast of Australia, covering tropical and temperate regions. Seven autosomal paracentric inversions and 1 apparently complex X chromosome arrangement were identified from these populations. All inverted arrangements were relatively more common in tropical populations; 2 common inversions showed clinal patterns over part of the range of D. serrata. Inversion polymorphism was relatively higher in tropical populations and almost absent in populations near the cooler southern border, in agreement with findings on other Drosophila species. While these patterns will complicate mapping of adaptive variation in D. serrata, they suggest that this species will be useful in investigatingthe dynamics of inversion-trait associations in natural populations.Key words: inversion polymorphism, geographic variation, latitudinal clines, Drosophila serrata.
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WATSON, JESSICA A., CAROL L. SPENCER, DREW R. SCHIELD, BRETT O. BUTLER, LYDIA L. SMITH, OSCAR FLORES-VILLELA, JONATHAN A. CAMPBELL, STEPHEN P. MACKESSY, TODD A. CASTOE, and JESSE M. MEIK. "Geographic variation in morphology in the Mohave Rattlesnake (Crotalus scutulatus Kennicott 1861) (Serpentes: Viperidae): implications for species boundaries." Zootaxa 4683, no. 1 (October 7, 2019): 129–43. http://dx.doi.org/10.11646/zootaxa.4683.1.7.
Повний текст джерелаАнотація:
The Mohave Rattlesnake (Crotalus scutulatus) is a highly venomous pitviper inhabiting the arid interior deserts, grasslands, and savannas of western North America. Currently two subspecies are recognized: the Northern Mohave Rattlesnake (C. s. scutulatus) ranging from southern California to the southern Central Mexican Plateau, and the Huamantla Rattlesnake (C. s. salvini) from the region of Tlaxcala, Veracruz, and Puebla in south-central Mexico. Although recent studies have demonstrated extensive geographic variation in venom composition and cryptic genetic diversity in this species, no modern studies have focused on geographic variation in morphology. Here we analyzed a series of qualitative, meristic, and morphometric traits from 347 specimens of C. scutulatus and show that this species is phenotypically cohesive without discrete subgroups, and that morphology follows a continuous cline in primarily color pattern and meristic traits across the major axis of its expansive distribution. Interpreted in the context of previously published molecular evidence, our morphological analyses suggest that multiple episodes of isolation and secondary contact among metapopulations during the Pleistocene were sufficient to produce distinctive genetic populations, which have since experienced gene flow to produce clinal variation in phenotypes without discrete or diagnosable distinctions among these original populations. For taxonomic purposes, we recommend that C. scutulatus be retained as a single species, although it is possible that C. s. salvini, which is morphologically the most distinctive population, could represent a peripheral isolate in the initial stages of speciation.