Faculty Publications

Molecular Evolution Of Cytochrome B Of Subterranean Mole Rats, Spalax Ehrenbergi Superspecies, In Israel

Document Type

Article

Keywords

Adaptation, Codon usage, DNA compositional bias, Mitochondrial cytochrome b, Molecular evolution, Speciation, Subterranean mammals, Transition-transversion ratio

Journal/Book/Conference Title

Journal of Molecular Evolution

Volume

49

Issue

2

First Page

215

Last Page

226

Abstract

We describe the molecular evolution of cytochrome b of blind subterranean mole rats. We examined 12 individuals for nucleotide differences in the region of 402 base pairs of mitochondrial cytochrome b. Each individual represents a different population from the entire ecological and speciational range of the four chromosomal species in Israel (2n = 52, 54, 58, and 60) belonging to the Spalax ehrenbergi superspecies. Our results indicate the following. (i) There are seven first-position transitional differences, compared to 34 variable third positions, with no observed second-position substitutions. (ii) A maximum of four amino acids differences occurs across the range. (iii) Within-species diversity increases southward. Only 1 autoapomorphic substitution characterizes either 2n = 52 or 2n = 54, but 6-11 substitutions characterize 2n = 58, and 9-13 substitutions characterize 2n = 60. (iv) Both parsimony and maximum-likelihood trees suggest two monophyletic groups: (a) 2n = 52 and 54, and (b) 2n = 58 and 60, as identified earlier by other protein and DNA markers. (v) Mitochondrial cytochrome b heterogeneity is significantly correlated with climatic factors (rainfall) and biotic factors (body size and allozymes). We hypothesize that two selective regimes direct cytochrome b evolution in the S. ehrenbergi superspecies: (i) purifying selection in the flooded, mesic, hypoxic northern range of 2n = 52 and 54 and (ii) diversifying selection in the climatically spatiotemporal, xeric, and variable southern range of 2n = 58 and 60. Thus, the molecular evolution of mitochondrial cytochrome b in S. ehrenbergi is explicable by opposite selective stresses across the range of S. ehrenbergi in Israel, associated with the ecological adaptive radiation of the complex.

Department

Department of Biology

Original Publication Date

8-9-1999

DOI of published version

10.1007/PL00006544

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