棉花种间BC_1群体偏分离的遗传剖析(英文)

Genetic Dissection of Segregation Distortion in Interspecific BC_1 Populations of Cotton

偏分离是指观察到的基因型频率偏离预期的孟德尔频率的遗传分离方式,在大多数的遗传定位研究中非常普遍。在之前我们发表的遗传连锁图中,107个SSR标记在BC1作图群体[(Emian 22×3-79)×Emian22]中表现偏分离。为阐明这些偏分离标记的遗传机制及其在其它群体中的偏分离情况,将其中97个共显性标记在另外两个回交群体中进行验证。结果表明,原图谱中的61个偏分离标记在另外2个回交群体中都表现正常分离,说明杂交方式是导致偏分离的一个重要因素。36个偏分离标记至少在两个群体中仍表现偏分离,偏分离应该是配子选择的结果。偏分离标记分布于14条染色体上,其中D亚基因组上的分布多于A亚基因组。偏分离标记在在第2、第16和第18染色体上分布最多,暗示在这些染色体上存在偏分离位点,该结果有助于在棉花中鉴定偏分离位点。

Segregation distortion （SD） is the deviation of genetic segregation ratios from their expected Mendelian fashion and is a common phenomenon found in most genetic mapping studies. In our previously genetic map published, 107 SSR markers showed SD in the BCI mapping population [（Emian 22×3-79） × Emian 22]. To verify their segregation in other populations and to clarify the possible mechanism of SD, 97 co-dominant markers of them were evaluated in another two backcross popula- tions. The results showed that 61 distorted markers in the mapping population segregated normally in the other backcross populations, which implied that the cross way is a major factor affecting segregation distortion. Thirty-six markers showed segregation distortion in at least two populations, which is assumed to be caused by gametic selection. These distorted markers distributed on 14 chromosomes with more markers in D sub-genome than in A sub-genome. Chr.2, Chr.16, and Chr.18 were the chromosomes with more distorted markers than others, which implies that there must be segregation distortion loci on these chromosomes, leading us to identify segregation distortion loci in cotton.