Diaz Iara Del Pilar Solar, de Camargo Gregório Miguel Ferreira, Cruz Valdecy Aparecida Rocha da, Hermisdorff Isis da Costa, Carvalho Caio Victor Damasceno, de Albuquerque Lucia Galvão, Costa Raphael Bermal
Escola de Medicina Veterinária e Zootecnia, Universidade Federal da Bahia (UFBA), Salvador, Brazil.
Universidade Federal do Oeste da Bahia (UFOB), Barra, Brazil.
Reprod Domest Anim. 2020 Nov;55(11):1650-1654. doi: 10.1111/rda.13810. Epub 2020 Sep 29.
Although the second largest chromosome of the genome, the X chromosome is usually excluded from genome-wide association studies (GWAS). Considering the presence and importance of genes on this chromosome that are involved in reproduction, the aim of this study was to evaluate the effect of its inclusion in GWAS on reproductive traits (scrotal circumference [SC], early pregnancy [P16] and age at first calving [AFC]) in a Nelore herd. Genotype data from 3,263 animals with the above-mentioned phenotypes were used. The results showed an increase in the variances explained by the autosomal markers for all traits when the X chromosome was not included. For SC, there was an increase of more than 10% for the windows on chromosomes 2 and 6. For P16, the effect was increased by almost 20% for windows on chromosome 5. The same pattern was found for AFC, with an increase of more than 10% for the most important windows. The results indicate that the noninclusion of the X chromosome can overestimate the effects of autosomes on SC, P16 and AFC not only because of the additive effect of the X chromosome itself but also because of its epistatic effect on autosomal genes.
尽管X染色体是基因组中第二大染色体，但它通常被排除在全基因组关联研究（GWAS）之外。考虑到该染色体上存在与繁殖相关的基因且这些基因很重要，本研究的目的是评估将其纳入GWAS对内洛尔牛群繁殖性状（阴囊周长[SC]、早期妊娠[P16]和初产年龄[AFC]）的影响。使用了来自3263头具有上述表型的动物的基因型数据。结果表明，当不纳入X染色体时，常染色体标记对所有性状解释的方差增加。对于SC，2号和6号染色体上的窗口增加了10%以上。对于P16，5号染色体上的窗口效应增加了近20%。AFC也发现了相同的模式，最重要的窗口增加了10%以上。结果表明，不纳入X染色体不仅会因为X染色体本身的加性效应，还会因为其对常染色体基因的上位效应而高估常染色体对SC、P16和AFC的影响。
