Abstract
The genetic dissection of closely related species is requisite for understanding the process of speciation. Inter-specific hybrid incompatibility represents species divergence and acts as a reproductive isolation barrier between species. Epistatic interactions have been a hallmark of hybrid incompatibility. However, no gene has been heretofore identified as interacting factor of any speciation genes. Nevertheless, previous studies showed that OdsH, a hybrid male sterility gene, requires other nearby interacting element(s) in the upstream of OdsH to confer full hybrid sterility effect. In order to identify the interacting elements of OdsH, two recombinant mappings were designed. The first recombinant mapping generated the sterile recombinant lines with introgression at OdsH downstream region (16D-17C) and demonstrated that there should be other interacting genes existed at downstream region to contribute complete hybrid male sterility. This result also indicates that the homeodomain across exons 2 and 3 of OdsH is essential in hybrid male sterility. In the second recombinant mapping, the fertility associated with mini-introgression segments showed that the interaction of multiple genes cause hybrid male sterility. I also found that the environmental factor, temperatures, is important in hybrid fitness when the fertility situations of hybrid males are identified as sub-fertile. It suggested that the genetic architecture of the hybrid male sterility contributed by OdsH is very complicated.