Multiple sex chromosome system X1X2X3Y1Y2 in the brown howler monkey Alouatta guariba clamitans (Atelidae, Platyrrhini)

STEINBERG, E.R.; MURER, L.; MUDRY, M.D.; FORTES, V.; LOVATO, M.; ROSSI, L.F.; MERANI, M.S.

Foz do Iguaçu

Congreso; 21st International Chromosome Conference; 2016

International Chromosome and Genome Society

In primates, the most widespread sex chromosome system is XX/XY. In all species of howler monkeys, genus Alouatta, multiple sex chromosome systems originated by Y-autosome translocations were observed. And only confirmed by meiotic analysis in 5 of them (X1X1X2X2/X1X2Y1Y2 in A. macconelli, A. caraya and A. pigra; X1X1X2X2/X1X2Y in A. belzebul and A. palliata). In the brown howler monkey Alouatta guariba clamitans, diploid numbers ranging from 2N=45 to 2N=52, with XX/XY, X1X1X2X2/X1X2Y and X1X1X2X2X3X3/X1X2X3Y1Y2 sex chromosome systems were described by mitotic studies, but not confirmed by meiotic ones. In this contribution we sampled 3 males in the wild (in the municipality of Santa María, RS, Brazil) and 1 male and 1 female in captivity at the São Braz breeding center. Peripheral blood samples and testicular biopsies were taken under anesthesia. Two techniques were performed in the latter: spermatocyte microspreads for synaptonemal complexes (SC) and the air-drying technique for the other stages. Inmunodetection was performed in spermatocyte microspreads using antibodies anti-SMC3 and anti-CREST. In somatic cells we observed different diploid numbers for both sexes: 2N=45, X1X2X3Y1Y2 and 2N=46, X1X1X2X2X3X3 with 3 metacentric chromosomal pairs (pairs 9-11), 7 submetacentrics (pairs 1-6, 8) and 10 acrocentrics (pairs 12-20, 22). X1 and X2 were submetacentric chromosomes, while X3, Y1 and Y2 were acrocentrics ones. The presence in the males of a sexual pentavalent X1X2X3Y1Y2 was confirmed by C-banding in metaphase I and inmunodetection in prophase I by the clear identification of 5 centromeres. The meiotic behavior was analyzed and compared with the chromosomal descriptions for other howler monkeys. Financial Support: UBACyT 20020100100136 MDM, PIP 0744 MDM, PIP 0168 MSM, License SISBIO 33876-2.