SPECIATION theory is still largely descriptive. How many and what kind of genes are implicated in speciation is a central unresolved problem of evolutionary biology1,2. Does speciation require major genomic changes3-5 or may minor ones suffice1,6-9? Similarly, does speciation depend on structural or on regulatory genes10? We have investigated these questions with reference to the actively speciating fossorial mole rats of the Spalax ehrenbergi complex in Israel, which comprises four morphologically indistinguishable chromosome forms (2n = 52, 54, 58, 60) 11 adapted in that order to increasing aridity12. Narrow hybrid zones between karyotypes13 and mate selection14 (through olfaction15, vocalisation16 and aggression 17) suggest that the recently18 formed species represent progressive stages of final speciation13. Genic diversity proved low, and genic similarity between karyotypes very high, in the previous test based on 17 gene loci of tissue proteins8. The test of eight additional loci of blood proteins, which is reported here, reinforces earlier conclusions and sheds light on the allozyme-environment association and on the amount of genetic differentiation during speciation.
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