Department of Biological Sciences, Graduate School of Science, University of Tokyo, Tokyo, Japan.
Mol Biol Evol. 2013 May;30(5):1038-40. doi: 10.1093/molbev/mst018. Epub 2013 Jan 30.
The molecular bases for the evolution of male-female sexual dimorphism are possible to study in volvocine algae because they encompass the entire range of reproductive morphologies from isogamy to oogamy. In 1978, Charlesworth suggested the model of a gamete size gene becoming linked to the sex-determining or mating type locus (MT) as a mechanism for the evolution of anisogamy. Here, we carried out the first comprehensive study of a candidate MT-linked oogamy gene, MAT3/RB, across the volvocine lineage. We found that evolution of anisogamy/oogamy predates the extremely high male-female divergence of MAT3 that characterizes the Volvox carteri lineage. These data demonstrate very little sex-linked sequence divergence of MAT3 between the two sexes in other volvocine groups, though linkage between MAT3 and the mating locus appears to be conserved. These data implicate genetic determinants other than or in addition to MAT3 in the evolution of anisogamy in volvocine algae.
雌雄异形的分子基础可能在绿色眼虫藻中进行研究，因为它们包含了从同配到异配的整个生殖形态范围。1978 年，Charlesworth 提出了配子大小基因与性别决定或交配型基因座（MT）相连的模型，作为异配性进化的机制。在这里，我们首次对绿色眼虫藻谱系中的一个候选 MT 连锁的卵配性基因 MAT3/RB 进行了全面研究。我们发现，异配性/卵配性的进化先于 MAT3 的极高雄性-雌性分化，而这种分化是 Volvox carteri 谱系的特征。这些数据表明，在其他绿色眼虫藻群体中，MAT3 在两性之间的性连锁序列分化很小，尽管 MAT3 与交配基因座之间的连锁似乎是保守的。这些数据表明，除了 MAT3 之外，还有其他遗传决定因素参与了绿色眼虫藻的异配性进化。
