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The evolution of geographic parthenogenesis in Timema walking‐sticks
Author(s) -
Law Jennifer H.,
Crespi Bernard J.
Publication year - 2002
Publication title -
molecular ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.619
H-Index - 225
eISSN - 1365-294X
pISSN - 0962-1083
DOI - 10.1046/j.1365-294x.2002.01547.x
Subject(s) - biology , clade , parthenogenesis , biological dispersal , phylogenetic tree , evolutionary biology , range (aeronautics) , cladistics , zoology , interspecific competition , ecology , genetics , population , demography , gene , embryo , materials science , sociology , composite material
Phylogenetic studies of asexual lineages and their sexual progenitors are useful for inferring the causes of geographical parthenogenesis and testing hypotheses regarding the evolution of sex. With five known parthenogens and well‐studied ecology, Timema walking‐sticks are a useful system for studying these questions. Timema are mainly endemic to California and they exhibit the common pattern of geographical parthenogenesis, with asexuals exhibiting more‐northerly distributions. Neighbour‐joining and maximum‐parsimony analyses of 416 bp of mitochondrial cytochrome oxidase I (COI) from 168 individuals were used to infer general phylogenetic relationships, resulting in three major phylogeographical subdivisions: a Northern clade; a Santa Barbara clade; and a Southern clade. A nested cladistic analysis, comparing intra‐ and interspecific haplotypic variation on a geographical scale, revealed that the overall pattern of geographical parthenogenesis in Timema could be attributed to historical range expansion. These results suggest that geographical parthenogenesis is the result of more‐extensive northerly dispersal of asexuals than sexuals.