Cytogénétique desLeggada: (1) La formule chromosomique deMus (Leggada)bufo Th., (2) Nouvelles données sur la délétion portant sur le bras court d'unX chezMus (Leggada)triton Th

Summary

The author treats 2 topics connected with his studies on the cytogenetics of the African pigmy-mice. (1)Mus (Leggada) bufo Th. shows the ‘primitive’ complement already detected in other species or subspecies (minutoides ssp₁,indutus, tenellus, setulosus): 2N=36,N.F.=36, sex chromosomesPR. (2) The deletion of the short arm of oneX-chromosome (X_dc) was previously observed as heterozygous mutation by 4 ♀♀ in a sample of 7♀♀ and 5 ♂♂. A more important sample (18 ♂♂, 21 ♀♀) gives the following results: 11 ♀♀X-X, 10 ♀♀X-X_dc, 18 ♂♂X-Y. The occurrence of ♀♀X_dc-X_dc and of ♂♂X_dc-Y is also very improbable. It is not easy to understand how the chromosomeX_dc may persist in the population if the complementsX_dc-X_dc andX_dc-Y are lethal, which seems to result from these observations.