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We studied the anatomical, histological, and genetic features of the sexual tract in four European mole species of the genus Talpa (Insectivora, mammalia): T. occidentalis, T. europaea, T. romana, and T. stankovici. All XY individuals had a normal male phenotype, whereas all XX individuals in all four species had features that identified them as intersexes. These individuals were nonetheless presumed to be functionally fertile females. Intersexuality was manifested mainly as gonadal hermaphroditism, with all females possessing bilateral ovotestes. The gonads were composed of a small portion of histologically normal ovarian tissue and a variably sized, generally large mass of disgenetic testicular tissue, accompanied by a small, rudimentary epididymis. The rest of the sexual tract was typically female, including oviducts, uterus, and vagina of normal appearance. Polymerase chain reaction (PCR) and Southern blotting analyses showed that the mammalian testis-determining gene SRY is present in males but not in females. Part of the conserved sequence of the mole SRY gene was cloned and sequenced after PCR amplification in two of the four mole species (T. occidentalis from Spain and T. romana from Italy). Sequences were identical in these two species and were very similar to those of the human and mouse SRY gene. Our findings constitute the first evidence of the existence of a genus-specific case of true hermaphroditism, probably due to a very ancient mutation that fixed in populations of the ancestral species from which contemporary moles evolved. The possible nature of this mutation is discussed with regard to the cytologic, histologic, and genetic features of the gonads in Talpa females.

As part of an extensive cytological study in natural populations of Thomas' pine vole Microtus thomasi, two cases of XXY aneuploidy (2n ¼ 45, FN ¼ 47) from different localities of NW Peloponnesus, Greece were recently recorded. These constitute the first report of sex chromosome aneuploidy for this species, in a sample of 366 individuals from 89 localities of Greece. Both individuals appeared with a male phenotype and normal morphology; however, measurements and histological examination in the testes of one of the two individuals imply a severely impaired fertility. The above findings translate to a relatively high rate of sex chromosome aneuploidy (0.55%) (upper 95% CI 1.96%) for the natural populations of Microtus thomasi and possible reasons for this are discussed.

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