Data di Pubblicazione:
2007
Citazione:
Independently evolving species in asexual bdelloid rotifers / D. Fontaneto, E. Herniou, C. Boschetti, M. Caprioli, G. Melone, C. Ricci, T.G. Barraclough. - In: PLOS BIOLOGY. - ISSN 1544-9173. - 5:4(2007 Mar 19), p. e87.
Abstract:
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.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Bdelloids; speciation; asexual reproduction
Elenco autori:
D. Fontaneto, E. Herniou, C. Boschetti, M. Caprioli, G. Melone, C. Ricci, T.G. Barraclough
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