Lampert Kathrin P, Lamatsch Dunja K, Epplen Jörg T, Schartl Manfred
Department of Physiological Chemistry I, University of Wuerzburg, Biozentrum, Am Hubland, 97074 Wuerzburg, Germany.
Evolution. 2005 Apr;59(4):881-9.
Asexual reproduction in vertebrates is rare and generally considered an evolutionary dead end. Asexuality is often associated with polyploidy, and several hypotheses have been put forward to explain this relationship. So far, it remains unclear whether polyploidization in asexual organisms is a frequent or a rare event. Here we present a field study on the gynogenetic Amazon molly, Poecilia formosa. We used multilocus fingerprints and microsatellites to investigate the genetic diversity in 339 diploid and 55 triploid individuals and in 25 P. mexicana, its sexual host. Although multilocus DNA fingerprints found high clonal diversity in triploids, microsatellites revealed only two very similar clones in the triploids. Phylogenetic analysis of microsatellite data provided evidence for a monophyletic origin of the triploid clones of P. formosa. In addition, shared alleles within the triploid clones between the triploid and diploid genotypes and between asexual and sexual lineages indicate a recent origin of triploid clones in Poecilia formosa.
脊椎动物中的无性繁殖很罕见，通常被认为是进化的死胡同。无性生殖常与多倍体相关，并且已经提出了几种假说来解释这种关系。到目前为止，尚不清楚无性生物中的多倍体化是频繁发生还是罕见事件。在此，我们展示了一项对雌核生殖的亚马孙帆鳉（Poecilia formosa）的野外研究。我们使用多位点指纹图谱和微卫星来研究339个二倍体和55个三倍体个体以及25个墨西哥帆鳉（其有性宿主）的遗传多样性。尽管多位点DNA指纹图谱发现三倍体具有高度的克隆多样性，但微卫星仅揭示了三倍体中的两个非常相似的克隆。微卫星数据的系统发育分析为亚马孙帆鳉三倍体克隆的单系起源提供了证据。此外，三倍体和二倍体基因型之间以及无性和有性谱系之间的三倍体克隆内共享等位基因表明，亚马孙帆鳉三倍体克隆起源较近。
