不同倍性泥鳅杂交后代染色体数目组成的研究

以泥鳅 Misgurnus anguillicaudatus 为研究对象,通过染色体计数法,对二倍体泥鳅与天然四倍体泥鳅正交(2n×4n)、反交(4n×2n)杂交后代的早期胚胎、6月龄及12月龄阶段的染色体数目进行了统计分析.结果表明:早期胚胎正、反杂交后代的染色体数目为67～81、67～82,在良好的中期分裂相(100、100个)中,染色体数目为75的整三倍体众数百分比最高(22％,20％),此外还有大量染色体数目＜75的亚三倍体(37％,51％)和染色体数目＞75的超三倍体(41％,29％)；6月龄正、反杂交后代的染色体数目为68～79、66～80,在良好的中期分裂相(58、63个)中,整三倍体(3n=75)众数百分比最高(26％,41％),此外还有大量亚三倍体(34％,49％)和超三倍体(40％,10％)；12月龄正、反杂交后代的染色体数目为68～82、69 ～83,在良好的中期分裂相(71、50个)中,三倍体(3n=75)众数百分比最高(28％,54％),此外还有大量亚三倍体(48％,20％)和超三倍体(24％,26％).研究表明,二倍体泥鳅与天然四倍体泥鳅正、反杂交后代均出现大量能存活的非整三倍体个体,并随养殖时间的延长,非整三倍体率呈下降趋势.

The chromosome sets stability of hybrid progeny in different ploidy loach

The early embryo,and 6-month old and 12-month old reciprocal crossed triploid progenies were obtained through the cross of diploid loach and natural tetraploid loach（original crossed 2n×4n,reciprocal crossed 4n×2n）,and these six hybrid groups were studied in this article.According to the method of chromosome counting,the chromosome amounts of these hybrid triploid progenies were counted and analysed.Consequently,the chromosome number of early embryonic cells of original crossed and reciprocal crossed progenies ranged from 67 to 81,67 to 82.The percentages of the number of triploid’s chromosome（3n=75） were 22% and 20% in one hundred well metaphases of the early embryonic cells.And this was the highest percent compared with other chromosome number in the same group.In addition,the hypo-triploid（3n〈75）（37%,51%） and hyper-triploid（3n〉75）（41%,29%） were found largely.The chromosome number of 6-month original crossed and reciprocal crossed progenies were in the range of 68 to 79,66 to 80.It was also the maximal percentage（26%,41%） in their respective group when the number of triploid’s chromosome was 75.Moreover,massive hypo-triploid（34%,49%） and hyper-triploid（40%,10%） were discovered.The chromosome quantities of 12-month original crossed and reciprocal crossed progenies varied from 68 to 82,69 to 83.Similarly,the percentage of the chromosome number（3n=75） was also higher than others in each group（28%,54%）.There were also findings many hypo-triploids（48%,20%） and hyper-triploids（24%,26%）.The findings showed that the reciprocal crossed triploid progenies were obtained through the hybridization of diploid loach（female and male） and natural tetraploid loach（male and female） were found lots of non integral triploid survived,the percentage of non integral triploids were downtrend with the prolonging cultural period and the percentage of original crossed non integral triploid was more than the percentage of reciprocal crossed non integral triploid.