The karyotype of Alouatta fusca clamitans from Rio de Janeiro, Brazil: Evidence for a y-autosome translocation

Abstract

The chromosome complements of four males of Alouatta fusca clamitans, caught in Rio de Janeiro State, Brazil, were analyzed by G-, C-, and NOR-banding techniques. The diploid number found was 49 in all the specimens. The presence of a heteromorphic pair of submetacentric chromosomes in the analyzed specimens, not present in males and females with 2n = 50 previously reported, and its G-banding pattern, led us to assume that this pair is involved in a Y-autosome translocation. Thus, the sex determination system appears modified to X1X1X2X2 /X1X2Y. Heterochromatic segments were found in the pericentromeric region of all the chromosomes, in the telomeric region of the short arm in pair 2, in the complete length of the short arm of pairs 5 and 6 and in the intercalary region of the long arm in pair 17. The nucleolar organizer regions were situated in the intercalary region of the long arm in two small acrocentric pairs.<br>Os cariótipos referentes a quatro machos de Alouatta fusca clamitans oriundos do Rio de Janeiro foram analisados através de técnicas de bandamento G, C e NOR. O número diplóide em todos os espécimes foi igual a 49, com a presença de três cromossomos não pareados. A comparação dos padrões de bandamento G com espécimes previamente descritos com 2n = 50 revelou a ocorrência de uma translocação do tipo Y-autossomo, modificando o sistema cromossômico de determinação sexual para o tipo múltiplo, X1X2Y/X1X1 X2X2. Os blocos de heterocromatina constitutiva se distribuíram na região pericentromérica de todos os cromossomos; segmentos intercalares e teloméricos foram visualizados em um par acrocêntrico e em outro submetacêntrico, respectivamente. As regiões organizadoras de nucléolo se localizaram no braço longo de dois pares de pequenos acrocêntricos

Cytochrome <i>b</i> sequences show subdivision between populations of the brown howler monkey (<i>Alouatta guariba</i>) from Rio de Janeiro and Santa Catarina, Brazil

“…The population differentiation we observe within A. guariba clamitans, along with the chromosomal differences previously described by Koiffmann (1977), Oliveira et al (1995Oliveira et al ( , 1996Oliveira et al ( , 1998Oliveira et al ( , 2000Oliveira et al ( , 2001Oliveira et al ( , 2002, and Gifalli (2003), may indicate that A. g. clamitans is actually representative of two distinct subspecies, or possibly even two separate species. Oliveira (2000) suggested that the large chromosomal differences characterizing these populations may indicate they are reproductively isolated from each other.…”

“…Howler monkeys show the greatest degree of karyological variation, both between and within species, of any platyrrhine genus (Koiffmann, 1977;Gifalli, 2003). Within Alouatta, A. guariba shows a notable degree of geographic chromosomal variation (Koiffmann, 1977;Oliveira et al, 1995Oliveira et al, , 1998Oliveira et al, , 2000Oliveira et al, , 2002 (Oliveira et al, 1995(Oliveira et al, , 2000(Oliveira et al, , 2002. Our ongoing efforts to karyotype all individuals in the preliminary cyt-b genealogy presented here should help to clarify the association between chromosomal and cyt-b results.…”

“…The southern populations tend to be larger in body size, with larger cranial and hyoid dimensions, and display greater sexual dichromatism (see Kinzey, 1982;Gregorin, 1996). Chromosomal variation is extensive in A. guariba: Koiffmann (1977), Oliveira et al (1995Oliveira et al ( , 1996Oliveira et al ( , 1998Oliveira et al ( , 2000Oliveira et al ( , 2001Oliveira et al ( , 2002, and Gifalli (2003) have reported large differences among populations, including chromosomal rearrangements and differences in diploid number (ranging from 2N = 45 to 52). To date very little information exists about genetic variation within A. guariba.…”

Geographical variation of cshromosomal numberin Alouatta fusca damitans (Primates, Atelidae)

“…Moreover, chromosomes B have been reported in A. seniculus (MINEZAWA et al 1985;LIMA et al 1991) and Y-autosome translocations have been observed in all the species: A. palliata (MA et al 1975), A. belzebul (ARMADA et al 1989SEUANEZ 1990), A. seniculus (YUNIS et al 1978;MINEZAWA et al 1987;LIMA et al 1991), A. fusca damitans (KOIFFMANN 1977DE OLIVEIRA et al 1998) andA. caraya (MUDRY et al 1998).…”

“…The chromosomes of Alouatta have been the subject of several research reports, and both inter-and intraspecific variation in the diploid number have been reported (MA et al 1975;LIMA and SEUANEZ 1989;ARMADA et al 1989; * Corresponding author: Institut fur Anthropologie und Humangenetik, Richard-Wagner Strasse, 10.1, 80333 Munich, Germany, e-mail: E.Oliveira@lrz.uni-muenchen.de LIMA et al 1991;MUDRY et al 1994MUDRY et al , 1998STANYON et al 1995;DE OLIVEIRA et al 1998). Moreover, chromosomes B have been reported in A. seniculus (MINEZAWA et al 1985;LIMA et al 1991) and Y-autosome translocations have been observed in all the species: A. palliata (MA et al 1975), A. belzebul (ARMADA et al 1989SEUANEZ 1990), A. seniculus (YUNIS et al 1978;MINEZAWA et al 1987;LIMA et al 1991), A. fusca damitans (KOIFFMANN 1977DE OLIVEIRA et al 1998) andA.…”