Banca de QUALIFICAÇÃO: ERICKA WANNESCKA DOS SANTOS

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
STUDENT : ERICKA WANNESCKA DOS SANTOS
DATE: 25/06/2021
TIME: 09:00
LOCAL: Realizado por videoconferência
TITLE:

Karyotypic reduction in the Apogonidae family (Kurtiformes): role of the chromosomal and biological patterns of the group

KEY WORDS:

Karyotypic evolution; In tandem fusion; chromosomal rearrangements, repetitive DNA, telomeric sequences.

PAGES: 68
BIG AREA: Ciências Biológicas
AREA: Genética
SUBÁREA: Genética Animal
SUMMARY:

The Apogonidae (Kurtiformes) family, known as cardinals, represents a very diverse group of reef fish, present in all oceans. Some of its species exhibit the rare buccal incubation behavior of eggs, which can influence the potential for dispersal of the species. This group has karyotypes with reduced diploid values (2n=34-46), but cytogenetic data for the family are still scarce. In this sense, the expansion of chromosomal data for the family, involving representatives from different oceans, represents a relevant evolutionary model of karyotype evolution. In order to understand the karyotypic evolution of the family, cytogenetic data are presented here that expand the phylogenetic spectrum, and allow to analyze them regarding the dispersive potential of the species and the organization of repetitive sequences in chromosomes. For this, conventional cytogenetic techniques were used (Giemsa staining, Ag-NORs and Cbanding); Fluorescent in situ mapping (FISH) of six repetitive DNA classes (18SrDNA, 5S rDNA; retrotransposon Rex3; Microsatellites (CA)15 and (CGG)10 and telomeric sequence) in the species Apogon americanus, Phaeoptyx pigmentaria (Atlantic Ocean), Sphaeramia nematoptera and Pterapogon kauderni (Indo-Pacific). The diploid numbers were reduced (2n=36, A. americanus; 2n=38, P. pigmentaria; and 2n=46, S. nematoptera and P. kauderni), especially in Atlantic species. The heterochromatic regions are reduced and the Ag-NORs/18S DNAr regions are simple and apparently located on a homeologous chromosome pair (larger submetacentric pair). The 18S and 5S rDNA sites are non-synthenic in Pacific species and co-located on the same chromosome pair in Atlantic species. The two microsatellite sequences, as well as Rex3, are scattered across chromosomes. The telomeric sequences exhibited interstitial telomeric sites (ITS) in A. americanus, indicating a karyotypic reduction mediated by the in tandem fusion mechanism with active participation of pericentric inversions. The family's karyotypic diversity contrasts with the numerical conservatism of other reef fish groups, suggesting a possible relationship with biological factors (buccal egg incubation), which reduce the dispersive potential and favor the group's karyotypic differentiation. The karyotypic characteristics of Apogonidae broadens the understanding of how biological and environmental factors (extrinsic factors) contribute as triggers for the high rate of chromosomal differentiation (intrinsic factors) in some groups of marine fish.

BANKING MEMBERS:
Presidente - 1199139 - WAGNER FRANCO MOLINA
Externo à Instituição - GIDEÃO WAGNER WERNECK FELIX DA COSTA
Externa à Instituição - KARLLA DANIELLE JORGE AMORIM