ABSTRACT
In this paper, the chromosome number of F9-F11 hybridis of Red crucian (Carassius auratus) x common carp(Cryprinus carpio) was examined by means of kidney cell-PHA culture. The results showed that F9-F11 allotetraploids possessed 200 chromosomes, with the karyotype formula 44 m + 68 sm + 44 st + 44 t, which were the same as the data indicated in F3-F8 allotetraploids. Both female and male of F9-F11 allotetraploids had the normal ovaries and testes that were able to produce the normal dipoid ova and sperm. In nature conditions, without the injection of the extraneous hormone, the females and males of F9-F11 allotetraploids mated each other to produce new generation of tetraploids. With the stable genetic tetraploidy and the fertility in the nature environments, this allotetraploid population presented the key factors to form a new species with 200 chromosomes.
Subject(s)
Carps/genetics , Gonads/cytology , Polyploidy , Animals , Carps/physiology , Female , Gonads/physiology , Karyotyping , Male , ReproductionABSTRACT
The tetraploid fish has been developed by assortative breeding the hybrids of Carassius auratus red var. (Female) x cyprinus carpio (Male), which has the stable genetic characters and can reproduce themselves. An "all-fish" recombinant DNA construct (pCAgcGHc) containing common carp beta-actin gene promoter and cDNA for grass carp (Ctenopharyngodon idella) growth hormone gene was introduced into fertilized eggs of the allotetroploid fish through microinjection as soon as artificial insemination was done. Artificial insemination was carried out between the female and the male transgenic allotetraploid fish which contain the "all-fish" recombinant DNA construct (pCAgcGHc) and are the biggest in the size. Fifty F1 samples of transgenic allotetraploid fish of 150 days and 50 allotetraploid fish (regarded as the control) were chosen, and the weight and the body length of each were measured, the results showed that F1 of transgenic allotetraploid fish of 150 days had obvious growth dominance compared with the control. Genomic DNA of tail fin was extracted from 20 F1 of transgenic allotetraploid fish of 150 days and the control. Proper primers were introduced to check whether the sample had the transgene. Pa, the upstream primer, is located in beta-actin promoter, and Pg, the downstream primer, is located in growth hormone cDNA for grass carp (gcGHc). The transgene was detected in 90% F1 of transgenic allotetraploid fish in tail fin DNA by polymerase chain reaction (PCR) amplification. Sperm could be squeezed out from a few F1 of transgenic allotetraploid fish of 150 days, however, this phenomenon did not exist in the controls. The importance of forming the pure line of transgenic allotetraploid was elucidate in the paper.
