A fine line between sex and unisexuality: the phylogenetic constraints on parthenogenesis in lacertid lizards |
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Authors: | ROBERT W MURPHY JINZHONG FU † ROSS D MACCULLOCH ILYA S DAREVSKY LARISSA A KUPRIYANOVA |
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Institution: | Centre for Biodiversity and Conservation Biology, Royal Ontario Museum, 100 Queen's Park, Toronto, Ontario, Canada M5S 2C6;Department of Zoology, University of Toronto, 25 Harbord St., Toronto, Ontario, Canada M5S 1A1;Zoological Institute, Russian Academy of Sciences, 119034 St. Petersburg, Russia |
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Abstract: | A phylogeny of Caucasian rock lizards (genus Darevskia , formerly Lacerta ) was reconstructed using mitochondrial DNA sequence and allozyme data. All 15 bisexual species grouped into three major clades: the caucasica, saxicola and rudis clades. Unisexual Darevskia originate from inter-clade hybridization, never from within clades. Only two clades, the caucasica clade and the rudis clade, were involved in forming unisexuals; the saxicola clade was never involved. Furthermore, the hybridization is directional in that the caucasica clade contributed only maternal parents and the rudis clade only paternal parents. The formation of unisexual species is best explained by sexually directional phylogenetic constraints. We hypothesize that the causative agents are likely to be genes linked with the sex chromosomes within the parental sexual species. |
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Keywords: | >Darevskia unisexuality sex chromosomes allozymes mtDNA sequences hybridization |
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