Gotowa bibliografia na temat „Pasmindo”

Pasmina svinja mangulica je stara pasmina svinja koja je imala veliku ulogu u hrvatskom stočarstvu u kojem se uzgaja više od stoljeće i pol, a u pojedinim razdobljima bila je najznačajnija pasmina svinja u Hrvatskoj, posebice u Slavoniji. Njezin značaj bio je velik u podmirenju prehrambenih potreba, ali i kao temelja nastanka hrvatske izvorna pasmine crna slavonska svinja. Danas se Hrvatskoj uzgaja mali broj jedinki ove pasmine, te u cilju očuvanja Hrvatska poljoprivredna agencija 2016. godine je započela postupak utemeljenja registra pasmine te u izradu programa očuvanja. Registar pasmine danas broji 113 rasplodnih grla nerasta i krmača, a zastupljena su sva tri tipa mangulice (bijeli, crveni i lasasti). Iako mangulica nije naša izvorna pasmina, duga tradicija uzgoja, njezin povijesni značaj u životu građana te uloga u stvaranju crne slavonske svinje, nesumnjivo su činjenice za ulaganje intenzivnog rada u očuvanju hrvatskog uzgoja mangulice te njezino svrstavanje u Popis izvorni i zaštićenih pasmina domaćih životinja Republike Hrvatske, a što potvrđuju brojni povijesni pisani dokazi i znanstvena istraživanja.

Fiziološke koncentracije spolnih hormona 17β-estradiola i testosterona varijaju s obzirom na vrstu životinje, dob, spol, pasminu, način držanja, hranidbu, stres i okolišne čimbenike. Navedeni hormoni su nužni za rast i razvoj životinje te njihovu spolnu zrelost i reproduktivnu funkciju. Zbog svog anaboličkog učinka koristili su se u prošlosti u intenzivnoj stočarskoj proizvodnji kao promotori rasta, putem stočne hrane ili u obliku implatanta. No, zbog svojih toksičnih učinaka u životinja i ljudi, uključujući mutagenost, kancerogenost i teratogenost, njihova je uporaba zabranjena u svrhu proizvodnje hrane životinjskog podrijetla. Danas je dopušteno korištenje prirodnih hormona samo u terapeutske svrhe za liječenje poremećaja reprodukcije i gravidnosti. S obzirom na stalni razvoj novih sintetskih tvari koje bi mogle imati anabolički učinak i mogu zlouporabu, nužno je tijekom redovitog provođenja kontrole te poznavanja fizioloških vrijednosti razina ovih hormona. Cilj ovog rada, uzimajući u obzir sve navedeno, bilo je istražiti razine prirodnih hormona 17β-estradiola i testosterona u krvi teladi različitog spola, pasmina, dobi i farmskog podrijetla na području Republike Hrvatske. U tu svrhu s tri različite farme na području Republike Hrvatske nasumično su izabrana 32 teleta različitog spola (5 muških i 27 ženskih), dobi 2 ‒ 5 mjeseci starosti, različitih pasmina i kategorija (13 teladi simentalske pasmine, 2 teladi mesne pasmine, 17 teladi holštajnske pasmine). Prilikom općeg kliničkog pregleda životinje od strane nadležnog veterinara, nisu primijećeni nikakvi znaci bolesti ili stanja koje bi mogle utjecati na razine ovih hormona. Prosječna razina 17β-estradiola iznosila je 28,8±11,0 ng/L. Koncentracija testosterona bila je niža od limita detekcije primjenjene analitičke metode u 24 uzorka plazme teladi, a detektirana je u 8 uzoraka s prosječnom koncentracijom od 126,7±167,5 ng/L, ukazujući na široku varijabilnost u koncentracijama ovog hormona. Statistički značajna razlika u koncentracijama određena je jedino za 17β-estradiol s obzirom na pasminski sastav i farmu podrijetla (P<0,05). S obzirom da su ustvrđene koncentracije u skladu s fiziološkim razinama iz ranije provedenih istraživanja u literaturi, u pretraživane teladi se može isključiti sumnja na ilegalnu uporabu sredstava s anaboličkim učinkom.Ključne riječi

Cilj istraživanja bio je utvrditi utjecaj pasmine i spola svinja na dnevni prirast u testu u proizvodnim uvjetima. Istraživanje je obuhvatilo 62 469 zapisa iz testa svinja u proizvodnim uvjetima od 1998. do 2017. godine u Republici Hrvatskoj. U istraživanje su bile uključene svinje četiri čiste pasmine: landras (L), veliki jorkšir (VJ), pietren (P), durok (D) te oba recipročna križanca LxVJ. Oba promatrana utjecaja imala su značajan utjecaj (P<0,05) na dnevni prirast. Uočena je statistički značajna razlika u dnevnom prirastu između pasmina. Prosjeci dobiveni metodom najmanjih kvadrata pokazuju da su svinje pasmine durok imale najveći dnevni prirast sa 583 g, zatim ih slijede križanci LxVJ sa 532 g i VJxL sa 529 g. Dnevni prirast za velikog jorkšira iznosi 528 g, a najmanji prirast je zabilježen kod pietrena sa 519 g. Utvrđena je značajna razlika (P<0,05) u dnevnom prirastu u testu u proizvodnim uvjetima između spolova (nerastića i nazimica) gdje prosječni dnevni prirast dobiven metodom najmanjih kvadrata iznosi 569 g u nerastića i 508 g u nazimica.

Dio teladi oteljenih na mliječnim farmama ili je neprikladan ili nije potreban za zamjenu muznog stada i kao višak se prodajom izlučuje iz uzgoja. U cilju utvrđivanja modela korištenja muške i križane teladi u mliječnim farmama u sustavu kontrole mliječnosti u Republici Hrvatskoj, anketirano je 1717 upravitelja mliječnih farmi. Najvećim dijelom muška telad prodaje se kao sisajuća ili mlada telad, a samo 26,6 % farmi je telad zadržalo u tovu do kategorije utovljene junadi. Prosječna dob pri prodaji je iznosila 47 dana, a do 30 dana starosti mušku telad je prodalo 56,8 % farmi. Očekivano, holštajn muška telad prodaje se ranije u odnosu na mušku telad drugih mliječnih pasmina. Pasmina ima veliki utjecaj na prodajnu dob i cijenu muške teladi, a simentalska telad je prodavana po najvećoj cijeni i u najstarijoj dobi. Velike farme ranije prodaju mušku telad, a između veličine muznog stada i dobi pri prodaji utvrđena je negativna korelacija (p<0,01). Muška telad prodavana je po prosječnoj cijeni od 332,14 €, a prodajna cijena bila je usko povezana s pasminom i dužinom uzgoja teladi na farmi. Prodajna cijena i razdoblje zadržavanja muške teladi na farmi razlikovala se između regija u kojoj se farme nalaze. Razlike u prosječnoj prodajnoj cijeni prema županijama rezultat su različitih pasminskih struktura i veličina muznih stada na mliječnim farmama. Utvrđeno je da na modele ekonomskog korištenja muške teladi značajan utjecaj imaju pasmina, veličina farme i regija u kojoj se farme nalaze.

Genetska raznolikost unutar autohtonih pasmina svinja se smanjuje kao posljedica smanjenja veličina populacija. Stoga se posljednjih godina posebna pozornost pridaje očuvanju genetske raznolikosti takvih pasmina. Cilj istraživanja bio je utvrditi genetsku raznolikost banijske šare svinje koristeći podatke o porijeklu životinja. Podaci o porijeklu sadržavali su 721 zapis o porijeklu svinja banijske šare pasmine u razdoblju od 2010 do 2017. godine. Referentna populacija sadržavala je sve životinje iz porijekla. Kvaliteta i cjelovitost pedigrea utvrđena je korištenjem slijedećih parametara: prosječni maksimalni broj generacija praćenih unatrag, prosječan broj punih generacija, te prosječan broj ekvivalentnih generacija. Genetska raznolikost populacije opisana je slijedećim parametrima: prosječni koeficijent uzgoja u srodstvu (F), stopa promjene koeficijenta uzgoja u srodstvu (ΔF), efektivna veličina populacije (Ne), prosječna srodnost u populaciji, te efektivni broj začetnika (Nef). Genetski intervali za četiri selekcijska puta izraženi su kao prosječna dob roditelja u trenutku rođenja potomaka. Prosječni maksimalni broj generacija iznosio je 2,47, prosječan broj punih generacija 1,50, dok je prosječni broj ekvivalentnih generacija iznosio 2,00. Prosječni koeficijent uzgoja u srodstvu iznosio je 3,68%, a stopa promjene uzgoja u srodstvu 1,74% po generaciji. Prosječna srodnost u populaciji iznosila je 9,32%, dok je efektivna veličina populacije iznosila 28,81. Prosječno trajanje generacijskog intervala iznosilo je 2,17 godine. Rezultati analize porijekla pokazali su potrebu za ulaganjem dodatnih napora kako bi se očuvala genetska raznolikost unutar populacije banijske šare svinje. Tome može pridonijeti plansko sparivanje životinja te primjena selekcije s optimiziranim doprinosom.

Cilj rada bio je opisati genetsku strukture te parametre genetske raznolikosti autohtonih pasmina svinja Hrvatske temeljem dosadašnjih podataka u dostupnoj literaturi. Očuvanju genetske raznolikosti autohtonih pasmina se posljednjih desetljeća pridaje sve veća pozornost jer predstavljaju kulturno i genetsko nasljeđe te zbog svoje otpornosti na bolesti i prilagodljivosti različitim uvjetima mogu imati važnu ulogu u popravljanju konstitucijskih svojstava hibrida i plemenitih pasmina. Povećana uporaba hibridnih linija i plemenitih pasmina u uzgoju i proizvodnji rezultirala je smanjenjem populacija izvornih pasmina te promjenom njihove genetske strukture. Kao posljedica navedenog, populacije izvornih pasmina imaju vrlo visoku stopu uzgoja u srodstvu, nisku genetsku raznolikost te vrlo često u ovakvim populacijama dolazi do procesa „uskog grla“. U cilju održavanja genetske raznolikosti hrvatskih autohtonih pasmina svinja potrebno je provoditi plansko sparivanje uz kontrolu podrijetla, praćenje održive stope uzgoja u srodstvu te provoditi selekciju s optimiziranim doprinosom u uzgojnim programima.

Puran se na širem području Hrvatskog zagorja uzgaja od 16. stoljeća. Nakon otkrića Novog svijeta vjerojatno je iz Srednje Amerike brodovima stigao u Europu, najvjerojatnije u Španjolsku, zatim u Englesku pa u Njemačku i Italiju, odakle se proširio i u naše krajeve. S vremenom se udomaćio, nije se križao s drugim pasminama pa je specifičan uzgoj u malim jatima koja su veći dio života provela na otvorenom u prirodi skupljajući hranu uvjetovao razvoj specifičnih morfoloških i fizioloških svojstava. Utjecao je na kvalitetu mesa, po čemu je zagorski puran poznat te se smatra specijalnom pasminom u gospodarskom smislu, a u uz to ima i veliko značenje kao vrijedan element biološke raznolikosti Hrvatske. U prošlosti se ova izvorna pasmina peradi slabo izučavala, tek nešto prije drugog svjetskog rata, iako je tada predstavljala značajan izvozni proizvod tradicionalnog uzgoja u zemlje zapadne Europe. Od drugog svjetskog rata do sredine devedesetih godina prošloga stoljeća zagorski puran gotovo je izumro i nestao. Svojom inicijativom i stručnošću, koncem devedesetih godina prošloga i početkom ovoga stoljeća spasili su ga pojedini entuzijasti i stručnjaci Agronomskog fakulteta u Zagrebu. Od tada se zagorski puran ozbiljnije istražuje, podupire i promovira, iako mu broj jedinki još uvijek varira na godišnjoj razini. U svakom je slučaju spašen, čak je u nekim inicijativama povremeno bio i ozbiljna robna marka kojoj, na kraju se pokazalo, treba stabilnost i kontinuitet uzgoja. Ovaj rad prikazuje stanje i gospodarske perspektive zagorskog purana u Varaždinskoj županiji.

In contrast to plant and animal cells, the fungal cells are multinucleate. A consequence of their multinucleate condition is heterokaryosis — the occurrence of genetically different nuclei in a common cytoplasm. In nature this condition occurs because of spontaneous mutations in the haploid nuclei in the coenocytic mycelium. Inspite of heterokaryosis being a fundamental aspect of fungal biology, the behaviour and dynamics of nuclei in fungal mycelium are little understood. This study was prompted by the following questions: (1) Why does a fungus need so many nuclei? (2) Are they all active simultaneously? (3) Does the proportion of the different nuclear types in fungal mycelium alter in response to change in conditions of growth? (4) Is the activity of an enzyme related to the dose of nuclei containing the encoding gene? Experimental approach. The approach taken was to generate heterokaryons in which one of the nuclear types carries a mutant allele for a specific enzyme while the other nuclear type carries the functional allele, introduced by transformation. Because in filamentous fungi, the transforming DNA commonly integrates randomly into the chromosomal DNA, the transformants would be genetic 'variants' in which the ratios of transformed to non-transformed nuclei might be controlled differently. The transformants could thus be useful in investigating the relationship between the frequency of transformed nuclei and the activity of encoded enzyme. In addition the transformants might be useful for studying nuclear behaviour. The availability of developmental information, genetic and molecular methodology, and biochemical mutant in Neurospora crassa made this fungus a material of choice for this investigation. Strain construction. A histidinol dehydrogenase (his-3) mutant strain was used into which an albino colour marker and a biochemical marker, inositoL were introduced by crossing. The latter two markers served as check against possible laboratory contamination. In addition, a gene mem, was introduced into the strain. In the mem genetic background, the strain has a wild-type morphology on agar medium but when grown in liquid shake culture it produces uninucleate microconidia that are useful in estimating nuclear ratio. Protoplasts of a constructed strain (his-3 al-1; mem; inl) were transformed with a plasmid containing the wild-type his-3 allele, thereby converting the original strain into a heterokaryotic strain having a mixture of transformed (his-3+t) and untransformed (his-3) nuclei. [The superscript +/ is used here to denote an his~3+ allele ectopically introduced by transformation]. Integration of plasmid DNA sequence in three selected transformants, 2T5, 3T3 and 4T12, was confirmed by genomic Southern analysis using the vector DNA as probe. The exponential growth rate of all three transformants was similar (~0.08mgh"1). Nuclear ratio. Assuming a uniform distribution of nuclei in mycelium, and a correspondence between nuclear ratio in mycelium and conidia, the ratio his-3* {: his-3 was estimated by plating microconidia. In transformant 3T3, the nuclear ratio was 7:1. In 2T5, all nuclei were his-3n. Transformant 4T12 did not produce microconidia. The nuclear ratio in this transformant was therefore estimated by macroconidial plating and found to be 1:5, in favour of his-3 nuclei. Behaviour of transformants in vegetative and sexual phase. Although the transformants had originally been selected for the expression of his-3+T gene, a majority of macroconidia produced in cultures of 3T3 and 2T5 required histidine to trigger their germination. This condition, referred to as cphenotypic lag', led to a gross underestimation of the proportion of prototrophic macroconidia by the direct plating method and biased the estimation of nuclear ratios. Therefore nuclear ratio was estimated by first germinating macroconidia on histidine supplemented medium before testing colonies in histidine dropout slants and comparing the numbers of auxotrophic and prototrophic mycelia. Phenotypic lag was not observed in 4T12. The variation in the degree of expression of phenotypic lag among the transformants was ascribed to transgene position effect. The transformants differed also in meiotic instability of the transforming DNA — the transforming DNA in 3T3 was passed through unchanged but it was deleted or modified in4T12and2T5. Experimental alteration of nuclear ratio. The transformants differed with respect to the self-adjusted ratio of transformed to non-transformed nuclei and also to the degree to which their nuclear ratio could be altered by nutritional manipulation of the growth medium, i.e., by growing the transformants in the presence or absence of histidine in the medium. In 3T3, the proportion of his-3+t nuclei progressively decreased by 3.5-fold in the sixth subculture on histidine medium. The change in 4T12 was even more striking: in the sixth serial subculture, the proportion of his-3+t nuclei decreased from 17-20% to -0.05%.However, when it was propagated again in medium that lacked histidine, the frequency of his-3+t nuclei was immediately restored to original level (-17%). That drastic alterations in nuclear ratio occurred upon nutritional manipulation was verified by Southern analysis. The intensity of signal specific for transformed DNA (nuclei) in cultures grown without histidine supplement was strong, but barely detectable in cultures grown with histidine. The signal reappeared when 4T12 was propagated in medium lacking histidine. Histidine induced change in nuclear ratio in 4T12 was further confirmed by three tests: (i) inoculum test using conidia, (ii) hyphal tip analysis, and (iii) genetic test using colour markers. Nuclear ratio and enzyme activity. Because in 4T12 changes in nuclear ratio could be manipulated, this transformant was used to investigate whether the proportion of his-3+t nuclei is correlated with the levels of encoded enzyme, histidinol dehydrogenase. Surprisingly, the specific activity of histidinol dehydrogenase was the same regardless of the percentage of his-3+t nuclei. This observation suggested that the physiological demand of a metabolite may be satisfied with only a few nuclei carrying the relevant gene. Or in other words the majority of nuclei in the coenocytic mycelium may, perhaps, not be active simultaneously. Silencing of transforming DNA in nuclei. Two experiments were done to test the possibility that in a majority of nuclei, the transforming DNA is selectively silenced by methylation of cytosine: (1) Southern analysis of chromosomal DNA digested with isoschizomers, and (2) Reactivation by growth of transformants in presence of 5-azacytidine, an inhibitor of methylation. The results suggested that a majority of transformed nuclei may, perhaps, be inactive. The results of Northern analysis suggested that the amount of his-3+t transcript was correlated (but 5-azacytidine experiment indicated that only few his-3+t nuclei may be active) with the proportion of his-3+t nuclei, but not histidinol dehydrogenase activity. The above results suggested that expression of his-3+t gene was controlled both at the levels of transcription and posttranscription. Nuclear selection. To study competition between nuclei containing mutant (his-3) nuclei and prototrophic nuclei containing his-3+ gene at its normal chromosomal location or at the ectopic location, heterokaryons were synthesized using strains in which the nuclear types had been marked by non-allelic genetic colour markers, al-1 and al-2. The results suggested that in heteronuclear mixture, the replication rate of the transformed nuclei is affected as compared to the nuclei having the gene in normal chromosomal location. Major contributions. This study generated (his-3 + his-3+) heterokaryons by transformation. The behaviour of transformants differed in some respects both in the vegetative and sexual phases. It was demonstrated that nuclear ratio could be experimentally altered. However, there was no correlation between nuclear ratio and enzyme activity. The observations imply asynchronous division rate among nuclei and raise the possibility that not all nuclei in the coenocytic mycelium are active simultaneously.

In contrast to plant and animal cells, the fungal cells are multinucleate. A consequence of their multinucleate condition is heterokaryosis — the occurrence of genetically different nuclei in a common cytoplasm. In nature this condition occurs because of spontaneous mutations in the haploid nuclei in the coenocytic mycelium. Inspite of heterokaryosis being a fundamental aspect of fungal biology, the behaviour and dynamics of nuclei in fungal mycelium are little understood. This study was prompted by the following questions: (1) Why does a fungus need so many nuclei? (2) Are they all active simultaneously? (3) Does the proportion of the different nuclear types in fungal mycelium alter in response to change in conditions of growth? (4) Is the activity of an enzyme related to the dose of nuclei containing the encoding gene? Experimental approach. The approach taken was to generate heterokaryons in which one of the nuclear types carries a mutant allele for a specific enzyme while the other nuclear type carries the functional allele, introduced by transformation. Because in filamentous fungi, the transforming DNA commonly integrates randomly into the chromosomal DNA, the transformants would be genetic 'variants' in which the ratios of transformed to non-transformed nuclei might be controlled differently. The transformants could thus be useful in investigating the relationship between the frequency of transformed nuclei and the activity of encoded enzyme. In addition the transformants might be useful for studying nuclear behaviour. The availability of developmental information, genetic and molecular methodology, and biochemical mutant in Neurospora crassa made this fungus a material of choice for this investigation. Strain construction. A histidinol dehydrogenase (his-3) mutant strain was used into which an albino colour marker and a biochemical marker, inositoL were introduced by crossing. The latter two markers served as check against possible laboratory contamination. In addition, a gene mem, was introduced into the strain. In the mem genetic background, the strain has a wild-type morphology on agar medium but when grown in liquid shake culture it produces uninucleate microconidia that are useful in estimating nuclear ratio. Protoplasts of a constructed strain (his-3 al-1; mem; inl) were transformed with a plasmid containing the wild-type his-3 allele, thereby converting the original strain into a heterokaryotic strain having a mixture of transformed (his-3+t) and untransformed (his-3) nuclei. [The superscript +/ is used here to denote an his~3+ allele ectopically introduced by transformation]. Integration of plasmid DNA sequence in three selected transformants, 2T5, 3T3 and 4T12, was confirmed by genomic Southern analysis using the vector DNA as probe. The exponential growth rate of all three transformants was similar (~0.08mgh"1). Nuclear ratio. Assuming a uniform distribution of nuclei in mycelium, and a correspondence between nuclear ratio in mycelium and conidia, the ratio his-3* {: his-3 was estimated by plating microconidia. In transformant 3T3, the nuclear ratio was 7:1. In 2T5, all nuclei were his-3n. Transformant 4T12 did not produce microconidia. The nuclear ratio in this transformant was therefore estimated by macroconidial plating and found to be 1:5, in favour of his-3 nuclei. Behaviour of transformants in vegetative and sexual phase. Although the transformants had originally been selected for the expression of his-3+T gene, a majority of macroconidia produced in cultures of 3T3 and 2T5 required histidine to trigger their germination. This condition, referred to as cphenotypic lag', led to a gross underestimation of the proportion of prototrophic macroconidia by the direct plating method and biased the estimation of nuclear ratios. Therefore nuclear ratio was estimated by first germinating macroconidia on histidine supplemented medium before testing colonies in histidine dropout slants and comparing the numbers of auxotrophic and prototrophic mycelia. Phenotypic lag was not observed in 4T12. The variation in the degree of expression of phenotypic lag among the transformants was ascribed to transgene position effect. The transformants differed also in meiotic instability of the transforming DNA — the transforming DNA in 3T3 was passed through unchanged but it was deleted or modified in4T12and2T5. Experimental alteration of nuclear ratio. The transformants differed with respect to the self-adjusted ratio of transformed to non-transformed nuclei and also to the degree to which their nuclear ratio could be altered by nutritional manipulation of the growth medium, i.e., by growing the transformants in the presence or absence of histidine in the medium. In 3T3, the proportion of his-3+t nuclei progressively decreased by 3.5-fold in the sixth subculture on histidine medium. The change in 4T12 was even more striking: in the sixth serial subculture, the proportion of his-3+t nuclei decreased from 17-20% to -0.05%.However, when it was propagated again in medium that lacked histidine, the frequency of his-3+t nuclei was immediately restored to original level (-17%). That drastic alterations in nuclear ratio occurred upon nutritional manipulation was verified by Southern analysis. The intensity of signal specific for transformed DNA (nuclei) in cultures grown without histidine supplement was strong, but barely detectable in cultures grown with histidine. The signal reappeared when 4T12 was propagated in medium lacking histidine. Histidine induced change in nuclear ratio in 4T12 was further confirmed by three tests: (i) inoculum test using conidia, (ii) hyphal tip analysis, and (iii) genetic test using colour markers. Nuclear ratio and enzyme activity. Because in 4T12 changes in nuclear ratio could be manipulated, this transformant was used to investigate whether the proportion of his-3+t nuclei is correlated with the levels of encoded enzyme, histidinol dehydrogenase. Surprisingly, the specific activity of histidinol dehydrogenase was the same regardless of the percentage of his-3+t nuclei. This observation suggested that the physiological demand of a metabolite may be satisfied with only a few nuclei carrying the relevant gene. Or in other words the majority of nuclei in the coenocytic mycelium may, perhaps, not be active simultaneously. Silencing of transforming DNA in nuclei. Two experiments were done to test the possibility that in a majority of nuclei, the transforming DNA is selectively silenced by methylation of cytosine: (1) Southern analysis of chromosomal DNA digested with isoschizomers, and (2) Reactivation by growth of transformants in presence of 5-azacytidine, an inhibitor of methylation. The results suggested that a majority of transformed nuclei may, perhaps, be inactive. The results of Northern analysis suggested that the amount of his-3+t transcript was correlated (but 5-azacytidine experiment indicated that only few his-3+t nuclei may be active) with the proportion of his-3+t nuclei, but not histidinol dehydrogenase activity. The above results suggested that expression of his-3+t gene was controlled both at the levels of transcription and posttranscription. Nuclear selection. To study competition between nuclei containing mutant (his-3) nuclei and prototrophic nuclei containing his-3+ gene at its normal chromosomal location or at the ectopic location, heterokaryons were synthesized using strains in which the nuclear types had been marked by non-allelic genetic colour markers, al-1 and al-2. The results suggested that in heteronuclear mixture, the replication rate of the transformed nuclei is affected as compared to the nuclei having the gene in normal chromosomal location. Major contributions. This study generated (his-3 + his-3+) heterokaryons by transformation. The behaviour of transformants differed in some respects both in the vegetative and sexual phases. It was demonstrated that nuclear ratio could be experimentally altered. However, there was no correlation between nuclear ratio and enzyme activity. The observations imply asynchronous division rate among nuclei and raise the possibility that not all nuclei in the coenocytic mycelium are active simultaneously.