Mishra Paras Kumar, Singh B N
Genetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi 221 005, India.
Indian J Exp Biol. 2005 May;43(5):455-61.
The genetic basis of hybrid male sterility among three closely related species, Drosophila bipectinata, D. parabipectinata and D. malerkotliana has been investigated by using backcross analysis methods. The role of Y chromosome, major hybrid sterility (MHS) genes (genetic factors) and cytoplasm (non-genetic factor) have been studied in the hybrids of these three species. In the species pair, bipectinata--parabipectinata, Y chromosome introgression of parabipectinata in the genomic background of bipectinata and the reciprocal Y chromosome introgression were unsuccessful as all males in second backcross generation were sterile. Neither MHS genes nor cytoplasm was found important for sterility. This suggests the involvement of X-Y, X-autosomes or polygenic interactions in hybrid male sterility. In bipectinata--malerkotliana and parabipectinata--malerkotliana species pairs, Y chromosome substitution in reciprocal crosses did not affect male fertility. Backcross analyses also show no involvement of MHS genes or cytoplasm in hybrid male sterility in these two species pairs. Therefore, X- autosome interaction or polygenic interaction is supposed to be involved in hybrid male sterility in these two species pairs. These findings also provide evidence that even in closely related species, genetic interactions underlying hybrid male sterility may vary.
利用回交分析方法，对三种近缘果蝇物种——双栉果蝇、拟双栉果蝇和马勒科特利亚果蝇之间杂交雄性不育的遗传基础进行了研究。在这三个物种的杂交后代中，研究了Y染色体、主要杂交不育（MHS）基因（遗传因子）和细胞质（非遗传因子）的作用。在双栉果蝇——拟双栉果蝇这一物种组合中，将拟双栉果蝇的Y染色体导入双栉果蝇的基因组背景以及反向导入Y染色体均未成功，因为第二代回交后代中的所有雄性均不育。未发现MHS基因和细胞质对不育有重要影响。这表明X - Y、X - 常染色体或多基因相互作用参与了杂交雄性不育。在双栉果蝇——马勒科特利亚果蝇和拟双栉果蝇——马勒科特利亚果蝇这两个物种组合中，正反交中Y染色体的替换均不影响雄性育性。回交分析还表明，这两个物种组合的杂交雄性不育中不存在MHS基因或细胞质的参与。因此，推测X - 常染色体相互作用或多基因相互作用参与了这两个物种组合的杂交雄性不育。这些发现也提供了证据，表明即使在近缘物种中，杂交雄性不育背后的遗传相互作用也可能不同。
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