Independently evolving species in asexual bdelloid rotifers

被引:288
作者
Fontaneto, Diego
Herniou, Elisabeth A.
Boschetti, Chiara
Caprioli, Manuela
Melone, Giulio
Ricci, Claudia
Barraclough, Timothy G. [1 ]
机构
[1] Univ London Imperial Coll Sci Technol & Med, Div Biol, Ascot SL5 7PY, Berks, England
[2] Univ Milan, Dipartimento Biol, I-20122 Milan, Italy
[3] Univ London Imperial Coll Sci Technol & Med, Nat Environm Res Council Ctr Populat Biol, Ascot SL5 7PY, Berks, England
[4] Univ Cambridge, Inst Biotechnol, Cambridge CB2 1TN, England
[5] Royal Bot Gardens, Jodrell Lab, Richmond, England
关键词
EVOLUTION; RECOMBINATION; INSIGHTS; CONSEQUENCES; LIKELIHOOD; DIVERSITY; SELECTION; ECOLOGY; TROPHI; IMPACT;
D O I
10.1371/journal.pbio.0050087
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Asexuals are an important test case for theories of why species exist. If asexual clades displayed the same pattern of discrete variation as sexual clades, this would challenge the traditional view that sex is necessary for diversification into species. However, critical evidence has been lacking: all putative examples have involved organisms with recent or ongoing histories of recombination and have relied on visual interpretation of patterns of genetic and phenotypic variation rather than on formal tests of alternative evolutionary scenarios. Here we show that a classic asexual clade, the bdelloid rotifers, has diversified into distinct evolutionary species. Intensive sampling of the genus Rotaria reveals the presence of well-separated genetic clusters indicative of independent evolution. Moreover, combined genetic and morphological analyses reveal divergent selection in feeding morphology, indicative of niche divergence. Some of the morphologically coherent groups experiencing divergent selection contain several genetic clusters, in common with findings of cryptic species in sexual organisms. Our results show that the main causes of speciation in sexual organisms, population isolation and divergent selection, have the same qualitative effects in an asexual clade. The study also demonstrates how combined molecular and morphological analyses can shed new light on the evolutionary nature of species.
引用
收藏
页码:914 / 921
页数:8
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