Chromosome Manipu Iations In The Polyploid Of Loach And Microsatellite Analysis

chromosomes operating mainly includes the polyploid induction, gynogenesis and androgenesis, and is important for fish genetic breeding.To explore the new methods for tetraploidy and androgenetic diploid for fish, the research selected the natural tetraploid and the diploid loach as experimental objects, utilized the cold shock treatment to suppress the second polar body release and induce the tetraploid, and then systematically analyzed the chromosome number, relative content, the volume of red blood cell nuclei and microsatellite DNA of the produced offspring. At the same time, the research also used the cold shock treatment to let the tetraploid loach generate androgenesis diploid. Next we analyzed the offspring with embryonic development, ploidy identification and microsatellite markers,the results are as follows:(1) Cold shock induced tetraploid loach: In this experiment, Identification results show the natural tetraploid loach major and minor and volume of tetraploid’s blood cells are significantly greater than the triploid(P <0.01). Direct measurement of DNA selection methods: Method measured by flow cytometry, a total of 147 yearlings induced offspring,which accounted for 78.9% tetraploid loach. three for each triploid and tetraploid from flow cytometry identified cells chromosome count that the number of what is thesame result(3n = 75,4n = 100). the results are consistent what three times Identification of methods.This test uses the 15 pairs of primers screened and 4 pairs of what(Mac24, Mac37, Mac63, Mac425) for the microsatellite analysis.The results showed that in the control group obtained experimentally induced tetraploid hybrids are genetic parents of the specific bands. Results by ploidy analysis and molecular marker analysis confirmed the 2n x 4n by cold shock inhibiting second polar body induced tetraploid successfully.(2) Androgenesis diploid of cold-shock induced natural teraploid:the average fertiliazation rate and the hatch rate between the contol group and the treatment group was significantly different(P> 0.05),but the difference of average survival rate after 7days between the control group(40.57%) and the treatment group(8.30%) was significant(P < 0.01).chromosome number of 20 single embryos randomly selected from the control group was 71-76, and the most of 75.Chromosome number of the treatment group was 46-80,16 of them were 2n=50,taking a highest mode percentage.This test uses the five pairs of primers, two pairs of polymorphic microsatellite loci(Mac45, Mac60) screening obtained Androgenesis and control groups were analyzed microsatellite markers, primers can be determined mother Mac45 the allelic positions and fragment size is 106/86, paternal genes for 51/53, and after the development of the male nucleus 51/53, 26.0%.Also in the primer Mac60 microsatellite markers Androgenesis paternal genetic offspring genotype 107/120, 126/134 without genetic maternal genotype, indicating Androgenesis offspring genome halving, only genetic material from male, no female gene expression. This test also one allele differs from the parental genotypes.In this study, cold shock only successfully induced natural tetraploid loach male diploid and cold shock-induced inhibition of the second polar body tetraploid success without that inactivation of ovum,the study results confirm the natural four ploidy tetraploid loach is a genetic group of four sets of chromosomes, which can produce the diploid(2n) gametes, polyploid breeding is carried out good material, but also provides a new production breeding ways for the whole male and polyploid.