Cytogenetic study in natural hybrids of Callithrix (Callitrichidae: Primates) in the Atlantic forest of the state of Rio de Janeiro, Brazil

• Published in: Iheringia. Série zoologia Vol. 101; no. 3; pp. 156 - 160
• Main Authors: Nogueira, D M, Ferreira, AMR, Goldschmidt, B, Pissinatti, A, Carelli, J B, Verona, CE
• Format: Journal Article
• Language: Portuguese
• Published: 30-09-2011
• Subjects: Callithrix; Callithrix aurita; Callitrichidae; Chromosomes; Data processing; Extinction; Forests; Habitat; Hybrids; Indigenous species; Introduced species; Karyotypes; Lymphocytes; Metaphase; Nucleoli; Pelage; Penicillata; Primates; Y chromosome
• ISSN: 0073-4721

In the Atlantic forest of Rio de Janeiro, Callithrix aurita (E. Geoffroy in Humboldt, 1812) is a native species vulnerable to extinction and C. jacchus (Linnaeus, 1758) and C. penicillata (E. Geoffroy, 1812) are invasive species. The major threats to the native species are habitat degradation and hybridization, although there are currently no genetic data about natural hybrids available. Previous studies have revealed that species of the Callithrix genus are extremely homogeneous in their karyotypes with the exceptions of the morphology and size of the Y chromosome and its nucleolar organizer region (NOR) banding pattern. Three male marmosets captured in the wild in Guapimirim municipality, Rio de Janeiro, Brazil, considered as possible hybrids between C. aurita and C. jacchus or C. penicillata on the basis of pelage pattern, were cytogenetically studied. Metaphase chromosomes were obtained by using short-term lymphocyte cultures and Ag-NOR staining was performed. The hybrids karyotypes were 2n=46, 14 uni- and 30 bi-armed autosomes, a median size submetacentric X and NOR bearing autosomes, being compatible with that observed for the genus. In the three individuals studied, Y chromosomes were similar to those found for C. aurita, without NORs. The data obtained suggest the involvement of C. aurita in natural hybridization with one of the invasive species. We discuss the possible consequences of this hybridization.Original Abstract: No estado do Rio de Janeiro, em area de Mata Atlantica, Callithrix aurita (E. Geoffroy in Humboldt, 1812) e a especie nativa considerada vulneravel a extincao e C. jacchus (Linnaeus, 1758) e C. penicillata (E. Geoffroy, 1812) sao especies invasoras. As principals ameacas a especie nativa sao a degradacao do habitat e a hibridacao, embora nao haja, ate o momento, dados geneticos que confirmem a hibridacao natural. Estudos anteriores revelaram que as especies do genero Callithrix sao extremamente homogeneas em seus cariotipos, diferindo quanto a morfologia do cromossomo Y e padrao de marcacao da rcgiao organizadora de nucleolo (NOR). No presente estudo, tres saguis machos capturados na natureza no municipio de Guapimirim, distrito de Teresopolis, RJ, considerados como possiveis hibridos entre C. aurita e C. jacchus ou C. penicillata, com base no padrao de pelagem, foram estudados citogeneticamente. Os cromossomos metafasicos foram obtidos pela tecnica de cultura de linfocitos e a coloracao Ag-NOR foi realizada. Os cariotipos dos hibridos, 2n=46, continham 14 autossomos com um braco e 30 com dois bracos, um cromossomo X de tamanho medio submetacentrico e marcacao NOR nos autossomos, sendo compativeis com aquele observado para o genero. Nos tres casos, o cromossomo Y foi similar ao observado em C. aurita, sem marcacao NOR. Os dados obtidos sugerem a participacao de C. aurita em hibridacao natural com as especies invasoras e suas provaveis consequencias sao discutidas.