Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-03-10T22:12:31Z No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-17T23:45:01Z (GMT) No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) / Made available in DSpace on 2016-03-17T23:45:01Z (GMT). No. of bitstreams: 1 MariaAparecidaFernandes_DISSERT.pdf: 1521396 bytes, checksum: d1543fe188d65d762caa9c3089c5b341 (MD5) Previous issue date: 2015-03-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq / A fam?lia Acanthuridae ? um grupo bastante representativo dentre os peixes marinhos e que desempenha um papel fundamental na din?mica ecol?gica dos recifes de corais. Tr?s esp?cies pertencentes ao g?nero Acanthurus s?o comuns ao longo dos recifes costeiros do Atl?ntico Ocidental: A. coeruleus, A. bahianus e A. chirurgus. No presente estudo, s?o apresentados dados citogen?ticos para estas tr?s esp?cies de Acanthurus com base em m?todos citogen?ticos cl?ssicos e no mapeamento de sequ?ncias ribossomais repetitivas, como DNAr 18S e 5S, al?m de sondas telom?ricas com a finalidade de auxiliar na compreens?o da carioevolu??o deste grupo. O padr?o citogen?tico dessas esp?cies indica que as etapas sequenciais de rearranjos cromoss?micos, que datam 19-5 milh?es de anos atr?s (Ma), s?o respons?veis por suas diferen?as interespec?ficas. Acanthurus coeruleus (2n=48; 2sm + 4st + 42a), A. bahianus (2n=36; 12m + 2sm + 4st + 18a) e A. chirurgus (2n=34; 12m + 2sm + 4st + 16a) compartilham um antigo conjunto de tr?s pares cromoss?micos originados atrav?s de invers?es peric?ntricas. Um conjunto de seis grandes pares metac?ntricos formados por transloca??es Robertsonianas (Rb) encontrado em A. bahianus e A. chirurgus e uma suposta fus?o em tandem presente em A. chirurgus s?o eventos mais recentes. A falta de sequ?ncias telom?ricas intersticiais (ITS), apesar de v?rias fus?es c?ntricas em A. bahianus e A. chirurgus pode estar relacionada com o longo per?odo de tempo ap?s a sua ocorr?ncia (estimado em 5 Ma). Al?m disso, as homeologias entre os pares de cromossomos que carregam os genes ribossomais, al?m de outras caracter?sticas estruturais, destacam grandes regi?es cromoss?micas conservadas nas tr?s esp?cies. Nossos resultados indicam que as mudan?as macroestruturais ocorreram durante a cladog?nese dessas esp?cies n?o foram seguidas por rearranjos microestruturais vis?veis nos cari?tipos. / The Acanthuridae family is a representative group from the marine fish that plays a key role in ecological dynamics of coral reefs. Three species are common along coastal reefs of Western Atlantic: Acanthurus coeruleus, Acanthurus bahianus and Acanthurus chirurgus. In the present study, cytogenetic data are presented for these three species Acanthurus based on classical cytogenetic methods and mapping of repetitive sequences such as ribosomal 18S and 5S rDNA and telomeric repeats to improve their karyotype evolutionary analyses. The cytogenetic pattern of these species indicated sequential steps of chromosomal rearrangements dating back 19 to 5 millions of years ago (M.a.) that accounted for their interspecific differences. A. coeruleus (2n=48; 2sm+4st+42a), A. bahianus (2n=36; 12m+2sm+4st+18a) and A. chirurgus (2n=34; 12m+2sm+4st+16a) share an older set of three chromosomal pairs that were originated through pericentric inversions. A set of six large metacentric pairs formed by Robertsonian (Rb) translocations found in A. bahianus and A. chirurgus and a putative in tandem fusion found in A. chirurgus are more recent events. The lack of interstitial telomeric sequences (ITS) in spite of several centric fusions in A. bahianus and A. chirurgus might be related to the long period of time after their occurrence (estimated in 5 M.a.). Furthermore, the homeologies among the chromosome pairs bearing ribosomal genes, in addition to other structural features, highlight large conserved chromosomal regions in the three species. Our findings indicate that macrostructural changes occurred during the cladogenesis of these species were not followed by conspicuous microstructural rearrangements in the karyotypes.