Chromosome painting in three-toed sloths: a cytogenetic signature and ancestral karyotype for Xenarthra

Autor(es)

Azevedo, Nathalia F. ^[1] ; Svartman, Marta ^[2] ; Manchester, Andrea ^[1] ; de Moraes-Barros, Nadia ^[1] ; Stanyon, Roscoe ^[3] ; Vianna-Morgante, Angela M. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biociencias, Dept Genet & Biol Evolut, BR-05408090 Sao Paulo - Brazil

^[2] Univ Fed Minas Gerais, Inst Ciencias Biol, Dept Biol Geral, BR-31270901 Belo Horizonte, MG - Brazil

^[3] Univ Florence, Dept Evolutionary Biol, I-50122 Florence - Italy

• Tipo de documento: Artigo Científico
• Fonte: BMC Evolutionary Biology; v. 12, MAR 19 2012.
• Citações Web of Science: 2

Resumo

Background: Xenarthra (sloths, armadillos and anteaters) represent one of four currently recognized Eutherian mammal supraorders. Some phylogenomic studies point to the possibility of Xenarthra being at the base of the Eutherian tree, together or not with the supraorder Afrotheria. We performed painting with human autosomes and X-chromosome specific probes on metaphases of two three-toed sloths: Bradypus torquatus and B. variegatus. These species represent the fourth of the five extant Xenarthra families to be studied with this approach. Results: Eleven human chromosomes were conserved as one block in both B. torquatus and B. variegatus: (HSA 5, 6, 9, 11, 13, 14, 15, 17, 18, 20, 21 and the X chromosome). B. torquatus, three additional human chromosomes were conserved intact (HSA 1, 3 and 4). The remaining human chromosomes were represented by two or three segments on each sloth. Seven associations between human chromosomes were detected in the karyotypes of both B. torquatus and B. variegatus: HSA 3/21, 4/8, 7/10, 7/16, 12/22, 14/15 and 17/19. The ancestral Eutherian association 16/19 was not detected in the Bradypus species. Conclusions: Our results together with previous reports enabled us to propose a hypothetical ancestral Xenarthran karyotype with 48 chromosomes that would differ from the proposed ancestral Eutherian karyotype by the presence of the association HSA 7/10 and by the split of HSA 8 into three blocks, instead of the two found in the Eutherian ancestor. These same chromosome features point to the monophyly of Xenarthra, making this the second supraorder of placental mammals to have a chromosome signature supporting its monophyly. (AU)

• Processo FAPESP: 03/11518-9 - Estudo da evolução do cromossomo X em mamíferos: mapeamento de genes do cromossomo X humano em duas espécies de marsupiais da família Didelphidae
• Beneficiário: Nathalia Fernandes de Azevedo
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 98/14254-2 - Centro de Estudos do Genoma Humano
• Beneficiário: Mayana Zatz
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 03/03212-7 - Origem e dispersao das populacoes de preguicas:estudo filogeografico e aspectos de conservacao biologica.
• Beneficiário: Nadia de Moraes Barros
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado