title: Association between single nucleotide polymorphisms and sexual precocity in Nellore heifers.
abstract: The aim of this study was to determine the extent (r2) of linkage disequilibrium (LD) in the genome of Nellore cattle, and to examine associations between single nucleotide polymorphisms (SNP) and age at first calving (AFC) and early pregnancy (EP) using a panel of high-density SNPs and data from 1182 Nellore females. A total of 13 contemporary groups (CG) were used consisting of farm, season, and year of birth. For genome-wide association analysis, SNPs with a minor allele frequency (MAF)<0.05 and animals with a call rate<0.90 were excluded, totaling 431,885 SNPs. For statistical analysis, a linear model was used for AFC and a threshold model for EP. To estimate the significance of the associations for the two traits, the model included the categorical fixed effects of CG, SNPs, and sire. In addition, the polygenic effect was included in the analysis. The additive effects and dominance deviations of Bonferroni-adjusted significant SNPs for AFC and EP were estimated using orthogonal contrasts. The average estimate of r2for all autosomes was 0.18 at a distance of 4.8kb and the mean MAF was 0.25±0.13. The LD decreased as the distance between markers increased: 0.35 (1kb) to 0.12 (100kb). Eleven significant associations were detected in seven different chromosomes. Seven SNPs were associated with AFC and four were associated with EP. Three SNPs were significant for both traits. The identification of SNPs associated with AFC and EP may contribute for selecting sexually precocious animals.
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: iregatieri@hotmail.com.
authors.forename: Inaê Cristina
authors.initials: IC
authors.lastname: Regatieri
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: arioneboligon@yahoo.com.br.
authors.forename: Arione Augusti
authors.initials: AA
authors.lastname: Boligon
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil; Veterinary Medicine and Animal Science School, Federal University of Bahia UFBA, Salvador, BA, Brazil. Electronic address: raphaelbcosta@gmail.com.
authors.forename: Raphael Bermal
authors.initials: RB
authors.lastname: Costa
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil; Department of Ecology, Zoology and Genetics, Capão do Leão Campus, Institute of Biology - IB, Federal University of Pelotas, 96010-900, Pelotas, RS, Brazil. Electronic address: fabiopablos@hotmail.com.
authors.forename: Fábio Ricardo Pablos
authors.initials: FRP
authors.lastname: de Souza
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: fernandobaldiuy@gmail.com.
authors.forename: Fernando
authors.initials: F
authors.lastname: Baldi
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: lutakada@gmail.com.
authors.forename: Luciana
authors.initials: L
authors.lastname: Takada
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: venturinigc@gmail.com.
authors.forename: Guilherme Costa
authors.initials: GC
authors.lastname: Venturini
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil; Veterinary Medicine and Animal Science School, Federal University of Bahia UFBA, Salvador, BA, Brazil. Electronic address: gregoriocamargo@hotmail.com.
authors.forename: Gregório Miguel Ferreira
authors.initials: GMF
authors.lastname: de Camargo
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: gerardojjunior@yahoo.com.br.
authors.forename: Gerardo Alves
authors.initials: GA
authors.lastname: Fernandes
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: tonhati@fcav.unesp.br.
authors.forename: Humberto
authors.initials: H
authors.lastname: Tonhati
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: oliveira.hn@gmail.com.
authors.forename: Henrique Nunes
authors.initials: HN
authors.lastname: de Oliveira
authors.affiliation: Department of Animal Science, Faculdade de Ciências Agrárias e Veterinárias, UNESP - Univ Estadual Paulista, Via de Acesso Prof. Paulo Donato Castellane, s/n, 14884-900, Jaboticabal, São Paulo, Brazil. Electronic address: lgalb@fcav.unesp.br.
authors.forename: Lucia Galvão
authors.initials: LG
authors.lastname: de Albuquerque
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle / Q000235:genetics*; D002418:Cattle Diseases / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D055106:Genome-Wide Association Study; D015810:Linkage Disequilibrium; D020641:Polymorphism, Single Nucleotide; D011247:Pregnancy; D011629:Puberty, Precocious / Q000235:genetics*; D012098:Reproduction / Q000235:genetics; D012741:Sexual Maturation / Q000235:genetics
keywords: Age at first calving; Beef cattle; Genome-wide association; Heifer pregnancy; Linkage disequilibrium