FEMALES OF 4 MOLE SPECIES OF GENUS TALPA (INSECTIVORA, MAMMALIA) ARE TRUE HERMAPHRODITES WITH OVOTESTES

We studied the anatomical, histological, and genetic features of the s exual tract in four European mole species of the genus Talpa (Insectiv ora, mammalia): T. occidentalis, T. europaea, T. romana, and T. stanko vici. All XY individuals had a normal male phenotype, whereas all XX i ndividuals in all four species had features that identified them as in tersexes. These individuals were nonetheless presumed to be functional ly fertile females. Intersexuality was manifested mainly as gonadal he rmaphroditism, with all females possessing bilateral ovotestes. The go nads were composed of a small portion of histologically normal ovarian tissue and a variably sized, generally large mass of disgenetic testi cular 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-determinin g gene SRY is present in males but not in females. Part of the conserv ed sequence of the mole SRY gene was cloned and sequenced after PCR am plification in two of the four mole species (T. occidentalis from Spai n and T. romana from Italy). Sequences were identical in these two spe cies and were very similar to those of the human and mouse SRY gene. O ur 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 d iscussed with regard to the cytologic, histologic, and genetic feature s of the gonads in Talpa females. (C) 1996 Wiley-Liss, Inc.