Cytogenetic study of the genus Saguinus (Callithrichidae, Primates)

Abstract

Eight subspecies from the genus Saguinus (S. fuscicollis fuscicollis, S. fuscicollis weddelli, S. bicolor bicolor, S. bicolor martinsi, S. mystax mystax, S. imperator imperator, S. midas midas, and S. midas niger) were studied. Five of them (S. f. fuscicollis, S. f. weddelli, S. b. martinsi, S. m. mystax and S. i. imperator) had their karyotypes described for the first time. Conventional coloration, banding patterns G, C and NOR, and G/C sequential banding tecniques were used. All samples showed the same diploid number (2n = 46). The patterns of the G, C and NOR bands were very similar with little differences in the quantity and constitutive heterochromatin distribution of the autosomes. Constitutive heterochromatin was observed only in telomeric regions of some chromosomes of S. f. fuscicollis and S. f. weddelli. The X chromosome was the same in all subspecies, but chromosome Y differed in size and morphology. XX/XY chimerism was verified in all subspecies<br>Oito subespécies do gênero Saguinus (S. f. fuscicollis, S. f. weddelli, S. b. bicolor, S. b. martinsi, S. m. mystax, S. i. imperator, S. m. midas e S. m. niger) foram estudadas citogeneticamente, das quais cinco (S. f. fuscicollis, S. f. weddelli, S. b. martinsi, S. m. mystax e S. i. imperator) tiveram seu cariótipo descrito pela primeira vez neste estudo. Os cariótipos foram analisados por coloração convencional, pelos padrões de bandas G, C e NOR, e pelo método de bandeamento sequencial G/C. Todos os espécimens mostraram o mesmo número diplóide (2n = 46 cromossomos) e os padrões de bandas G, C e NOR foram muito similares entre as subespécies, diferindo apenas na quantidade e distribuição de heterocromatina constitutiva de alguns autossomos. Heterocromatina constitutiva presente na região telomérica de alguns cromossomos foi observada apenas em S. f. fuscicollis e S. f. weddelli. O cromossomo X foi igual em todas subespécies, porém, o cromossomo Y diferiu em morfologia e tamanho. Quimerismo cromossômico XX/XY foi verificado em todas as subespécies

Repetitive Sequence Distribution on Saguinus, Leontocebus and Leontopithecus Tamarins (Platyrrhine, Primates) by Mapping Telomeric (TTAGGG) Motifs and rDNA Loci

“…C-banding data ( Figure 1 b) obtained in the present work agrees with literature [ 9 , 11 ]. In the species of the genus Saguinus, heterochromatin is mainly restricted to centromeric position in both biarmed and acrocentric chromosomes.…”

“…The species were karyotyped by 4′,6-diamidino-2-phenylindole (DAPI) inverted banding: after DAPI staining of metaphases chromosomes, pictures were analysed through the software Adobe Photoshop to get the inverted DAPI staining. The karyotypes matched published Giemsa Banding data for S. geoffroyi [ 7 ], S. oedipus [ 7 , 13 ], S. mystax, Leontocebus fuscicollis [ 9 , 11 , 12 ] and Leontopithecus rosalia [ 12 , 13 ]. Chromosomes were classified according to the nomenclature proposed by Levan et al [ 33 ].…”

“…The species of the genus Saguinus have rather similar G-banded karyotypes with differences in heterochromatin distribution, as revealed by a C-banding comparison. Indeed, many species of the genera Saguinus , Leontopithecus and Leontocebus fuscicollis share the same diploid number 2n = 46 but differ mainly by the C-banding pattern [ 6 , 7 , 8 , 9 , 10 , 11 , 12 ]; for example, Saguinus midas and Leontopithecus rosalia have similar chromosome morphologies, but they differ through a paracentric inversion and four pericentric inversions, as well as through the distribution and quantity of heterochromatin [ 11 , 12 ].…”

Proposed chromosomal phylogeny for the South American primates of the Callitrichidae family (Platyrrhini)

“…Although numerous, they have not explained the phylogenetic relations between the taxa. Diploid numbers with 44 and 46 chromosomes occur with the following complements: 2n = 44 with 10 acrocentric and 32 bi-armed autosomes, found in Cebuella pygmaea [Seuánez et al, 1988;Nagamachi et al, 1992;Nagamachi, 1995] and in the argentata group of Callithrix Nagamachi, 1995;Nagamachi et al, 1994Nagamachi et al, , 1996Canavez et al, 1996]; and 2n = 46 with 14 acrocentric and 30 bi-armed autosomes, observed in the jacchus group of Callithrix [Bedard et al, 1978;Ardito et al, 1983Ardito et al, , 1987Nagamachi & Ferrari, 1984, 1986Seuánez et al, 1988;Nagamachi et al, 1997a], in Saguinus [Schmid & Glasser, 1977;Bedard et al, 1978;Benirschke et al, 1982;Marczynska et al, 1983;Nagamachi & Pieczarka, 1988;Nagamachi et al, 1990;Dantas & Barros, 1997] and in Leontopithecus [Peixoto et al, 1981;Sbalqueiro et al, 1992;Nagamachi, 1995;Nagamachi et al, 1997b]. Only Seuánez et al [1988] described a complement of 12 acrocentrics and 32 bi-armed autosomes for Leontopithecus.…”

Germ-line chimerism and paternal care in marmosets ( Callithrix kuhlii )

“…Although there is little doubt that tissues derived from hematopoietic origin are universally chimeric (9), the existence of chimeric cells in nonhematopoietic tissues, including germ-line cells, has not been established. Karyotypic analysis of C. jacchus revealed that testes cells express unusual orientation during meiosis, and this evidence suggested that the germ-line cells might include female cells present because of chimerism (8,10).…”