Identificação e caracterização de variantes genéticas associadas à pelagem em gado zebuíno
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Data
2022-02-22
Autores
Trigo, Beatriz Batista
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Universidade Estadual Paulista (Unesp)
Resumo
O gado zebuíno da raça Nelore (Bos indicus) é conhecido por sua fácil adaptação nos ambientes de climas tropicais e subtropicais. Uma das características fenotípicas relacionadas à essa adaptação e principalmente à tolerância à radiação ultra-violeta é o padrão de coloração da pele e da pelagem apresentado pela raça. Outras raças zebuínas também apresentam padrão de pelagem semelhante ao Nelore. Dada a potencial contribuição da variação na pelagem destes animais na adaptação dos mesmos nos climas tropicais e sub-tropicais, objetivou-se mapear variantes genéticas candidatas estruturais ou funcionais que estivessem associadas ao escurecimento da pelagem nos zebuínos. Realizando análise de associação genômica ampla (genome-wide association study – GWAS) e posterior análise de dados de sequenciamento completo foi possível encontrar uma complexa variante estrutural nas proximidades do gene da proteína sinalizadora agouti (agouti signaling protein -ASIP) a qual foi denominada de ASIP-SV1, sendo fortemente correlacionada ao escurecimento da pelagem em regiões específicas no corpo dos bovinos das raças Nelore e Brahman. A variante estrutural ASIP-SV1 também foi predita como sendo de origem B. indicus, para confirmar tal predição foram analisadas sequencias da região da variante estrutural de animais zebuínos e não-zebuínos para elucidar a segregação desta variante. Nas análises realizadas 45,3% dos zebuínos analisados apresentaram a variante estrutural enquanto que dos taurinos somente 6.3% continham a variante no gene ASIP sendo que esses taurinos eram de raças conhecidas por apresentarem introgressão zebuína em seu genoma. Concluiu-se que a variante ASIP-SV1 causa o escurecimento na pigmentação da pelagem em regiões específicas do corpo destes animais causando um aumento na produção de eumelanina, a variante se mostrou robusta e sugeriu-se que, em conjunto a outros genes, essa variação possa contribuir com a adaptação dos bovinos aos climas tropicais e sub-tropicais.
Indicine Nellore cattle (Bos indicus) had as main characteristic their adaptation in tropical and subtropical climate. The pigmentation of skin and coat color are both phenotype characteristics related to its climate adaptation and heat tolerance. Several indicine breeds also had the same coat color pattern as shown by Nellore cattle. Given the potential contribution of coat color variation on their adaptation in tropical and subtropical environments the aim of the study was to map candidate genetic structure or functional variants associated with darkness of hair coat in zebu cattle. Using genome-wide association study (GWAS) and latter analysis of whole-genome sequence it was possible to identity a complex structural variant in vicinity of agouti signaling protein (ASIP) gene named as ASIP-SV1, being strongly correlated to darkness of hair coat in specific body regions of Nellore and Brahman cattle. ASIP-SV1 was also predicted to be B. indicus origin. To confirm this prediction, it was analyzed sequences from ASIP-SV1 region from indicine and non-indicine cattle to elucidate this variant segregation. It was possible to identify 45.3% from zebu animals analyzed showing ASIP-SV1 while only 6.3% from taurine animals analyzed had this structural variant. The taurine cattle with ASIP-SV1 in ASIP gene is known to had zebu introgression on their genome. It was possible to conclude that ASIP-SV1 variant cause the darkness of hair coat on specifics regions of the body of these animals increasing eumelanin production, the variant shows to be robust and results suggest that ASIP-SV1, in a set of other genes, should play a role on cattle tropical and subtropical climate adaptation.
Indicine Nellore cattle (Bos indicus) had as main characteristic their adaptation in tropical and subtropical climate. The pigmentation of skin and coat color are both phenotype characteristics related to its climate adaptation and heat tolerance. Several indicine breeds also had the same coat color pattern as shown by Nellore cattle. Given the potential contribution of coat color variation on their adaptation in tropical and subtropical environments the aim of the study was to map candidate genetic structure or functional variants associated with darkness of hair coat in zebu cattle. Using genome-wide association study (GWAS) and latter analysis of whole-genome sequence it was possible to identity a complex structural variant in vicinity of agouti signaling protein (ASIP) gene named as ASIP-SV1, being strongly correlated to darkness of hair coat in specific body regions of Nellore and Brahman cattle. ASIP-SV1 was also predicted to be B. indicus origin. To confirm this prediction, it was analyzed sequences from ASIP-SV1 region from indicine and non-indicine cattle to elucidate this variant segregation. It was possible to identify 45.3% from zebu animals analyzed showing ASIP-SV1 while only 6.3% from taurine animals analyzed had this structural variant. The taurine cattle with ASIP-SV1 in ASIP gene is known to had zebu introgression on their genome. It was possible to conclude that ASIP-SV1 variant cause the darkness of hair coat on specifics regions of the body of these animals increasing eumelanin production, the variant shows to be robust and results suggest that ASIP-SV1, in a set of other genes, should play a role on cattle tropical and subtropical climate adaptation.
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Palavras-chave
Bovinos, ASIP, Genética animal, Bovine, Animal genetics