The major initial mechanism of ecological speciation in subterranean blind mole rats (Spalacidae) is chromosomal, primarily through Robertsonian rearrangements. Here we show that pericentric inversions followed by genic divergence may also lead to ecological speciation and adaptive radiation. Diversity was assessed along a transect of 250 km across the range of mole rats in Jordan from mesic Irbid in the north to xeric Wadi Musa (Petra region) in the south. Twelve populations of the Spalax ehrenbergi superspecies were examined for chromosome morphology (N = 71), body size (N = 76), and allozyme (N = 67) diversities, encoded by 32 loci. By a combination of chromosome morphology, genetic distance, body size, and ecogeography, we identified four new putative biological species. All species (except 2 animals in Madaba) share the 2n = 60 karyotype, but vary in chromosome morphology due to pericentric inversions and/or centromeric shifts. The "North Moav" species is karyotypically polymorphic (2n = 60; 2 animals with 2n = 62). The distribution of the four species is associated with different ecogeographical domains and climatic diversity: Gilead, North Moav, South Moav, and Edom separated by the rivers Zarqa, Kafrain, Arnon, and Zered. 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 combinatorically chromosome, allozyme, and size diversities. It is hypothesized that mole rat evolution underground in Jordan is intimately associated with climatic diversity stress aboveground.
|Number of pages||1|
|Journal||Israel Journal of Zoology|
|State||Published - 2000|
ASJC Scopus subject areas
- Animal Science and Zoology