doctoralThesis
Evolução cariogenômica em peixes recifais das famílias Acanthuridae (Acanthuriformes) e Holocentridae (Holocentriformes)
Fecha
2019-08-30Registro en:
FERNANDES, Maria Aparecida. Evolução cariogenômica em peixes recifais das famílias Acanthuridae (Acanthuriformes) e Holocentridae (Holocentriformes). 2019. 102f. Tese (Doutorado em Sistemática e Evolução) - Centro de Biociências, Universidade Federal do Rio Grande do Norte, Natal, 2019.
Autor
Fernandes, Maria Aparecida
Resumen
The families Acanthuridae and Holocentridae are groups of marine fish with high
representation in coral reefs, where they play important ecological functions in
environmental balance. Biological, phylogeographic and taxonomic aspects of these
families are widely known, however, their cytogenetic aspects are incipient. In order to
increase the knowledge about karyotypic evolution and possible interpopulation
cytogenetic variations, four species of Acanthuridae (A. coeruleus, A. bahianus and A.
chirurgus - Western Atlantic; and Acanthurus triostegus - Indian) and three
Holocentridae species were analyzed. (Myripristis jacobus, Holocentrus adscensionis
- West Atlantic; and Sargocentron rubrum – Indian Ocean). The analyzes used
conventional cytogenetic techniques, base-specific fluorochrome staining and
repetitive sequence mapping of 18S rDNA, 5S rDNA, histones H3 and H2B-H2A,
microsatellites (GA)15, Tol2 transposons and Rex3 retrotransposon through
fluorescent in situ hybridization. Between Acanthuridae, A. triostegus showed a
karyotypic pattern considered basal for Percomorpha (2n = 48; NF = 48), while West
Atlantic species exhibited a sequential karyotypic divergence associated with
phylogenetic divergence. Interpopulation variation of 18S rDNA sites was identified
between A. coeruleus populations of the Western Atlantic and Caribbean. The
mapping of 18S rDNA, 5S rDNA, DNAhis H2B-H2A and H3 sites showed
microstructural patterns in the Acanthurus genus. Holocentric species M. jacobus and
S. rubrum presented 2n = 48 acrocentric chromosomes, while H. adscensionis, 2n =
50 (2m + 6sm + 16st + 26a). In this group the 18S and 5S rDNA sites constitute
discriminating cytotaxonomic markers, where Rex elements and microsatellite repeats
(GA)15 were co-located. Despite the wide geographical distances, no interpopulation
variations were observed in M. jacobus and H. adscensionis. The results indicated a
more diverse horotelic evolution in Atlantic Acanthurus species, with latest
diversification, in relation to A. triostegus, belonging to the Indo-Pacific, center of origin
of this group. While the presence of 2n = 48a karyotypes in Holocentrinae
(Sargocentron) and Myripristinae (Myripristis) species, highlights the sharing of a
conserved condition in Percomorpha and suggests an ancestral condition for the
Holocentriformes. Both groups reveal phylogenetic divergences, but also the
maintenance of chromosomal homeologies, and possible signs of population variation (A. coeruleus), highlighting the importance of cytogenomic analyzes correlated with biogeographic patterns in understanding karyotypic changes in marine groups.