The major initial mechanism of speciation in subterranean blind mole rats, Spalacidae, is chromosomal, primarily through Robertsonian rearrangements. Here we highlight another scenario of chromosomal rearrangement leading to ecological speciation and adaptive radiation apparently initiated by pericentric inversions and genic divergence to different ecologies in mole rats in Jordan. We analysed karyotype, allozyme, size and ecological diversity across the range of mole rats in Jordan from mesic Irbid in the north to xeric Wadi Musa (Petra region) in the south, a transect of 250 km. We examined mole rats for chromosome (N=71), size (N=76), and allozyme (N=67) diversities, encoded by 32 loci, in 12 populations of the Spalax ehrenbergi superspecies in Jordan. By a combination of chromosome morphology, genetic distance, body size and ecogeography, we identified four new putative biological species. All species (except two animals in Madaba) share 2n=60 but vary in chromosome morphology, caused by pericentric inversions and/or centromeric shifts. The 'north Moav' species is karyotypically polymorphic for 2n (2n=60; including locally also two animals with 2n=62). The distribution oF the four species is associated with ecogeographical different domains and climatic diversity. Genetic diversity indices were low, but like chromosome arms (NFa) were positively correlated with aridity stress. Discriminant analysis correctly classified 91% of the individuals into the four species utilizing combinatorially chromosome, allozyme and size diversities. It is hypothesized that mole rat evolution underground is intimately associated with climatic diversity stress above ground. (C) 2000 The Linnean Society of London.
Bibliographical noteFunding Information:
We are deeply indebted to Mr Adnan Budieri, Head of Research and Survey, the Royal Society for the Conservation of Nature, Jordan, for kindly permitting us to collect the mole rats in the Kingdom of Jordan. We thank Avi Morgenstern and Abdul Naser El Hueiti for field assistance. We are grateful to Carlo Redi and Abraham Korol, and three anonymous reviewers for comments that improved the manuscript. We thank for financial support the Israeli Ministry of Absorption; The Human Frontiers Science Program (HFSP RG-68/95), the Israeli Discount Bank Chair of Evolutionary Biology and the Ancell–Teicher Research Foundation for Genetics and Molecular Evolution.
- Blind mole rats
- Pericentric inversions
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics