Banca de DEFESA: NATALIA BIANCA CAIRES MEDEIROS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : NATALIA BIANCA CAIRES MEDEIROS
DATA : 09/03/2020
HORA: 09:00
LOCAL: Belém
TÍTULO:

Study of genetic variants in the CSN1S1 and CSN3 genes in Murrah buffalo females.


PALAVRAS-CHAVES:

Buffalo. Milk. Polymorphism. Sequencing. SNP.


PÁGINAS: 47
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
SUBÁREA: Genética e Melhoramento dos Animais Domésticos
RESUMO:

The characteristics of milk are controlled by several genes, with emphasis on the four casein genes, CSN1S1; CSN1S2; CSN2 and CSN3, which are responsible for encoding the four fractions of that protein, are they, α-casein which includes α (S1) and α (S2), β and κ-casein. The study of genetic variants in these genes, seek to investigate alleles, insertions or deletions, which may reflect directly on productive characteristics, indicating differences in quality, composition, and milk yield. Thus, the objective of this study is to investigate the occurrence of polymorphisms in the CSN1S1 and CSN3 genes in buffalo females of the murrah breed. The CSN1S1 and CSN3 genes were analyzed in 41 lactating murrah buffaloes, using nucleotide sequencing. The primer pairs amplified fragments of 313 bp for the CSN1S1 gene, and 350 bp for the CSN3 gene. An SNP was found in the amplified fragment for the CSN1S1 gene, located in the nucleotide number 2,123 of the promoter region (5 'UTR), at position nt-258 (A / G), which did not cause any amino acid changes. The observed genotype frequencies of this SNP were 0.59 (AA); 0.38 (AG) and 0.03 (GG), while the expected genotypic frequencies (EHW - Hardy-Weinberg Equilibrium), presented different values, of 0.61 (AA), 0.34 (AG) and 0, 05 (GG). In addition, the observed heterosigosity (Ho) was higher than the expected heterosexuality (He) (0.3846 vs. 0.3408), thus suggesting an excess of heterozygotes in relation to the Hardy equilibrium model -Weinberg. As for the CSN3 gene, two SNPs nt-98 and nt-102 (nucleotides number 377 and 381 of exon number 4, of the CSN3 gene) were identified in codons 33 (ACC / ATC) and 34 (AC C / AC T) of the analyzed fragment, which correspond to codons 135 and 136 of the mature peptide, and which, once translated, result in the amino acids Threonine (Thr) / Isoleucine (Ile), in the case of the ATC / ACT haplotypes and Threonine / Threonine, for the ACC / ACC haplotypes. According to the frequency analysis for the CSN3 gene, it was possible to observe 0.53 for the CC genotype, 0.41 (CT) and 0.06 (TT). Regarding the expected genotype frequencies (EHW), they resulted in values of 0.54 (CC), 0.39 (CT) and 0.07 (TT). And again, the observed heterosigosity (Ho) was greater than the expected heterosigosity (He) (0.4118 vs. 0.3893), thus suggesting an excess of heterozygotes in relation to the (EHW) model. The knowledge of candidate gene polymorphisms in dairy buffaloes suggests and encourages studies that aim to establish associations between such variants in candidate genes, and characteristics of milk production and its derivatives, enabling the selection assisted by molecular markers.


MEMBROS DA BANCA:
Externo ao Programa - 1487106 - CRISTIAN FATURI
Externo ao Programa - 1557097 - IGOR GUERREIRO HAMOY
Interno - 1957010 - MARILIA DANYELLE NUNES RODRIGUES
Externo à Instituição - ROMMEL THIAGO JUCA RAMOS - UFPA
Notícia cadastrada em: 27/02/2020 16:49
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