Abstract
Oryza sativa is classified into two main subspecies, indica and japonica. Various reproductive isolations that are supposed to act as important factors in evolution have been observed between them. However attempts to identify the causal genes have been discouraged by their complexity. Here, we isolated DOPPELGANGER (DPL) 1 and 2 located on chromosome 1 and 6. They were revealed to be paralogous genes and to act as a pair of reproductive isolation genes between indica cv. Kasalath and japonica cv. Nipponbare. The hybrid pollen having both Kasalath DPL1 allele (DPL1-K) and Nipponbare DPL2 allele (DPL2-N) failed in pollen germination. Expression and sequence analyses suggested that DPL1-K and DPL2-N have lost their function. DPL structure is highly conserved among angiosperms, suggesting an essential role in pollen germination. Evolutionary analysis revealed multiple duplications and losses of DPL in angiosperm evolution.
