title: Identification of Candidate Genes for Reactivity in Guzerat (Bos indicus) Cattle: A Genome-Wide Association Study.
abstract: Temperament is fundamental to animal production due to its direct influence on the animal-herdsman relationship. When compared to calm animals, the aggressive, anxious or fearful ones exhibit less weight gain, lower reproductive efficiency, decreased milk production and higher herd maintenance costs, all of which contribute to reduced profits. However, temperament is a trait that is complex and difficult to assess. Recently, a new quantitative system, REATEST®, for assessing reactivity, a phenotype of temperament, was developed. Herein, we describe the results of a Genome-wide association study for reactivity, assessed using REATEST® with a sample of 754 females from five dual-purpose (milk and meat production) Guzerat (Bos indicus) herds. Genotyping was performed using a 50k SNP chip and a two-step mixed model approach (Grammar-Gamma) with a one-by-one marker regression was used to identify QTLs. QTLs for reactivity were identified on chromosomes BTA1, BTA5, BTA14, and BTA25. Five intronic and two intergenic markers were significantly associated with reactivity. POU1F1, DRD3, VWA3A, ZBTB20, EPHA6, SNRPF and NTN4 were identified as candidate genes. Previous QTL reports for temperament traits, covering areas surrounding the SNPs/genes identified here, further corroborate these associations. The seven genes identified in the present study explain 20.5% of reactivity variance and give a better understanding of temperament biology.
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Fernanda Caroline
authors.initials: FC
authors.lastname: Dos Santos
authors.affiliation: Embrapa Gado de Leite, Juiz de Fora, Brazil.
authors.forename: Maria Gabriela Campolina Diniz
authors.initials: MG
authors.lastname: Peixoto
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Pablo Augusto de Souza
authors.initials: PA
authors.lastname: Fonseca
authors.affiliation: Embrapa Gado de Leite, Juiz de Fora, Brazil.
authors.forename: Maria de Fátima Ávila
authors.initials: MF
authors.lastname: Pires
authors.affiliation: Center for Genetic Improvement of Livestock, University of Guelph, Guelph, Canada.|Beef Improvement Opportunities, Guelph, Canada.
authors.forename: Ricardo Vieira
authors.initials: RV
authors.lastname: Ventura
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Izinara da Cruz
authors.initials: ID
authors.lastname: Rosse
authors.affiliation: Embrapa Gado de Leite, Juiz de Fora, Brazil.
authors.forename: Frank Angelo Tomita
authors.initials: FA
authors.lastname: Bruneli
authors.affiliation: Embrapa Gado de Leite, Juiz de Fora, Brazil.
authors.forename: Marco Antonio
authors.initials: MA
authors.lastname: Machado
authors.affiliation: Departamento de Biologia Geral, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.
authors.forename: Maria Raquel Santos
authors.initials: MR
authors.lastname: Carvalho
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle; D002874:Chromosome Mapping; D033481:Chromosomes, Mammalian / Q000737:chemistry; D004843:Epistasis, Genetic; D005260:Female; D059647:Gene-Environment Interaction; D005819:Genetic Markers; D055106:Genome-Wide Association Study; D005838:Genotype; D010641:Phenotype; D040641:Quantitative Trait Loci; D019655:Quantitative Trait, Heritable; D013694:Temperament
chemical_list: D005819:Genetic Markers