Meiosis and chromosome painting of sex chromosome systems in Ceboidea

The identity of the chromosomes involved in the multiple sex system of Alou atta caraya (Aca) and the possible distribution of this system among other Ceboidea were investigated by chromosome painting of mitotic cells from fiv e species and by analysis of meiosis at pachytene in two species. The ident ity of the autosome #7 (X-2) involved in the multiple system of Aca and its breakage points were demonstrated by both meiosis and chromosome painting. These features are identical to those described by Consigliere et al. [199 6] in Alouatta seniculus sara (Assa) and Alouatta seniculus arctoidea (Asar ). This multiple system was absent in the other four Ceboidea species studi ed here. However, data from the literature strongly suggest the presence of this multiple in other members of this genus. The presence of this multipl e system among several species and subspecies that show high levels of chro mosome rearrangements may suggest a special selective value of this multipl e. The meiotic features of the sex systems of Aca and Cebus apella paraguay anus (Cap) are strikingly different at pachytene, as the latter system is s imilar to the sex pair of man and other primates. The relatively large gene tic distances between species presently showing this multiple system sugges t that its origin is not recent. Other members of the same genus should be investigated at; meiosis and by chromosome painting in order to know the ex tent and distribution of this complex sex-chromosome system. Am. J. Primato l. 54:65-78, 2001. (C) 2001 Wiley-Liss, Inc.