INTERBREEDINGS BETWEEN KARYOTYPIC ALPINE RACES OF THE COMMON SHREW SOREX-ARANEUS (INSECTIVORA, MAMMALIA)

Controlled interbreedings were performed between distinct chromosomal races or forms of Sorex araneus coming from populations of Swiss and F rench Alps. Four mating pairs including homozygous individuals of the Vaud race, the Valais race, the Intermediate Vaud-Acrocentric form and the Acrocentric form have led to several heterozygous hybrid litters. The karyotypes of the parents were determined from cultures of cartil aginous cells. The karyotypes of the offsprings were determined with a classical method. The production of hybrids between different races s uggests the absence of postmating barrier between the Vaud race and th e Intermediate form, the Acrocentric form and the Intermediate form, t he Acrocentric form and the Valais race.