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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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/20068 |
| Date | 26 March 2015 |
| Creators | Fernandes, Maria Aparecida |
| Contributors | 56615043491, http://lattes.cnpq.br/8437464961129518, Chellappa, Sathyabama, 15644812472, http://lattes.cnpq.br/4657086910453785, Artoni, Roberto Ferreira, 13854979800, http://lattes.cnpq.br/8875928930712027, Molina, Wagner Franco |
| Publisher | Universidade Federal do Rio Grande do Norte, PROGRAMA DE P?S-GRADUA??O EM SISTEM?TICA E EVOLU??O, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/masterThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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