Takada Luciana, Barbero Marina M D, Oliveira Henrique N, de Camargo Gregório M F, Fernandes Júnior Gerardo A, Aspilcueta-Borquis Rusbel R, Souza Fabio R P, Boligon Arione A, Melo Thaise P, Regatieri Inaê C, Feitosa Fabieli L B, Fonseca Larissa F S, Magalhães Ana F B, Costa Raphael B, Albuquerque Lucia G
Departamento de Zootecnia-São Paulo State University-UNESP, Jaboticabal, São Paulo, Brazil.
PLoS One. 2018 Jan 2;13(1):e0190197. doi: 10.1371/journal.pone.0190197. eCollection 2018.
Reproductive traits are of the utmost importance for any livestock farming, but are difficult to measure and to interpret since they are influenced by various factors. The objective of this study was to detect associations between known polymorphisms in candidate genes related to sexual precocity in Nellore heifers, which could be used in breeding programs. Records of 1,689 precocious and non-precocious heifers from farms participating in the Conexão Delta G breeding program were analyzed. A subset of single nucleotide polymorphisms (SNP) located in the region of the candidate genes at a distance of up to 5 kb from the boundaries of each gene, were selected from the panel of 777,000 SNPs of the High-Density Bovine SNP BeadChip. Linear mixed models were used for statistical analysis of early heifer pregnancy, relating the trait with isolated SNPs or with haplotype groups. The model included the contemporary group (year and month of birth) as fixed effect and parent of the animal (sire effect) as random effect. The fastPHASE® and GenomeStudio® were used for reconstruction of the haplotypes and for analysis of linkage disequilibrium based on r2 statistics. A total of 125 candidate genes and 2,024 SNPs forming haplotypes were analyzed. Statistical analysis after Bonferroni correction showed that nine haplotypes exerted a significant effect (p<0.05) on sexual precocity. Four of these haplotypes were located in the Pregnancy-associated plasma protein-A2 gene (PAPP-A2), two in the Estrogen-related receptor gamma gene (ESRRG), and one each in the Pregnancy-associated plasma protein-A gene (PAPP-A), Kell blood group complex subunit-related family (XKR4) and mannose-binding lectin genes (MBL-1) genes. Although the present results indicate that the PAPP-A2, PAPP-A, XKR4, MBL-1 and ESRRG genes influence sexual precocity in Nellore heifers, further studies are needed to evaluate their possible use in breeding programs.
繁殖性状对任何家畜养殖都至关重要，但由于受多种因素影响，难以测量和解释。本研究的目的是检测与内洛尔小母牛性早熟相关的候选基因中已知多态性之间的关联，这些关联可用于育种计划。分析了参与Conexão Delta G育种计划的农场中1689头早熟和非早熟小母牛的记录。从高密度牛SNP芯片的777,000个SNP中，选择位于候选基因区域内、距每个基因边界最多5 kb的单核苷酸多态性（SNP）子集。线性混合模型用于早期小母牛怀孕的统计分析，将该性状与单个SNP或单倍型组相关联。该模型包括当代组（出生年份和月份）作为固定效应，动物的亲本（父系效应）作为随机效应。使用fastPHASE®和GenomeStudio®重建单倍型，并基于r2统计分析连锁不平衡。总共分析了125个候选基因和形成单倍型的2024个SNP。经Bonferroni校正后的统计分析表明，九个单倍型对性早熟有显著影响（p<0.05）。其中四个单倍型位于妊娠相关血浆蛋白A2基因（PAPP-A2）中，两个位于雌激素相关受体γ基因（ESRRG）中，一个分别位于妊娠相关血浆蛋白A基因（PAPP-A）、凯尔血型复合物亚基相关家族（XKR4）和甘露糖结合凝集素基因（MBL-1）中。尽管目前的结果表明PAPP-A2、PAPP-A、XKR4、MBL-1和ESRRG基因影响内洛尔小母牛的性早熟，但仍需要进一步研究以评估它们在育种计划中的可能用途。
