Banca de DEFESA: DALVAN HENRIQUE LUIZ ROMEIRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : DALVAN HENRIQUE LUIZ ROMEIRO
DATE: 11/10/2021
TIME: 14:00
LOCAL: Realizada por videoconferência: Google meet
TITLE:

Contrasts of chromosomal evolution and repetitive DNA diversification in angelfishes (Pomacanthidae, Teleostei)

KEY WORDS:

rDNA, Histones, Karyotypic evolution, repetitive DNA, Reef fishes.

PAGES: 81
BIG AREA: Ciências Biológicas
AREA: Genética
SUBÁREA: Genética Animal
SUMMARY:

Karyotypic stasis processes and intense chromosomal changes exemplify extreme phenomena of karyotypic changes. Some groups of marine fishes have both conditions reflected in the karyotypes of their species. One of these groups, Pomacanthidae, presents 12% of the species with karyotypes with a high degree of conservatism in the diploid number (2n = 48), but with karyotype structures that can be very divergent. Here are presented cytogenetic data of six species of the family, Pomacanthus paru, P. arcuatus, Holacanthus tricolor, H. ciliaris, Centropyge aurantonotus (Atlantic ocean), and C. eibli (Indian ocean), obtained by conventional methods and fluorescent in situ hybridization of six repetitive DNA classes (rDNAs, microsatellites, transposable elements, histones) that demonstrate the karyotypic diversity and contrasting patterns of chromosomal evolution of the group. The analyzed species share the same diploid number (2n = 48), with karyotypes formed mainly by acrocentric chromosomes, except for C. aurantonotus, which exhibits a large profusion of bi-brachial elements. Despite the numerical and structural conservatism of karyotypes, there were variations in the distribution and organization of some repetitive DNA classes. All species exhibited only one 18S rDNA loci, while the 5S rDNA regions were more variable, occurring in most chromosomes of C. aurantonotus. Pomacanthus paru and P. arcuatus, with recent divergence, exhibit very similar karyotypes, including the arrangements of the 18S rDNA sites, but differ in the positioning of the 5S rDNA regions. Holacanthus species showed considerable variation in number and position of histone H4 sites. The occurrence of evolutionary traits related to chromosomal structure and organization of repetitive sequences in some species indicate disruptive events on the limited karyotypic diversification of the group, mediated by pericentric inversions and heterochromatinization processes.

BANKING MEMBERS:
Externo à Instituição - CLÓVIS COUTINHO DA MOTTA NETO - UnP
Externo à Instituição - GIDEÃO WAGNER WERNECK FELIX DA COSTA
Presidente - 1199139 - WAGNER FRANCO MOLINA