文章基本信息

标题：Extreme clonal diversity and divergence in populations of a selfing hermaphroditic fish
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作者：B J Turner ; J F Elder ; T F Laughlin 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1992
卷号：89
期号：22
页码：10643-10647
DOI：10.1073/pnas.89.22.10643
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Recombination is unknown in natural populations of Rivulus marmoratus, a selfing hermaphrodite, and genetic variation is likely due to mutation alone. DNA fingerprinting with an array of microsatellite [e.g., (CT)9] and minisatellite (e.g., the 33.15 core sequence) probes reveals very high clonal diversity within samples of seven Floridian populations, of which five contain about as many clones as there are individuals. There are 42 clones among 58 individuals surveyed (mean, 1.4 individuals per clone), a level of genetic diversity unprecedented among clonal animals. Moreover, all of the probes recognize the same clones even though, at high hybridization stringencies, there is little overlap in the fingerprint patterns they generate. This suggests that most sympatric clones differ by multiple and independent mutational steps. In one population studied in detail, the average number of mutational steps separating two clones is estimated at 9 or 10 and may be substantially higher. The mutational discontinuities among sympatric clones make it unlikely that they evolved by accumulation of neutral mutations in populations that are otherwise genetically uniform. The data argue that the mixing of unrelated individuals from different local populations occurs to an extent previously unappreciated and/or that divergence of clones is mediated by natural selection. If confirmed, the latter would be a serious challenge to current ideas on the predominant role of recombination in promoting the evolution of biological novelty.