Sabahat Sajida, Nadeem Asif, Brauning Rudiger, Thomson Peter C, Khatkar Mehar S
Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Syed Abdul Qadir Jilani (Outfall) Road, Lahore 54000, Pakistan.
The University of Sydney, School of Life and Environmental Sciences, 425 Werombi Road, Camden NSW 2570, Australia.
Anim Biosci. 2023 Jul;36(7):1010-1021. doi: 10.5713/ab.22.0181. Epub 2022 Nov 14.
Growth performance and growth-related traits have a crucial role in livestock due to their influence on productivity. This genome-wide association study (GWAS) in Pakistani dromedary camels was conducted to identify single nucleotide polymorphisms (SNPs) associated with growth at specific camel ages, and for selected SNPs, to investigate in detail how their effects change with increasing camel age. This is the first GWAS conducted on dromedary camels in this region.
Two Pakistani breeds, Marecha and Lassi, were selected for this study. A genotypingby-sequencing method was used, and a total of 65,644 SNPs were identified. For GWAS, weight records data with several body weight traits, namely, birthweight, weaning weight, and weights of camels at 1, 2, 4, and 6 years of age were analysed by using model-based growth curve analysis. Age-specific weight data were analysed with a linear mixed model that included fixed effects of SNP genotype as well as sex.
Based on the q-value method for false discovery control, for Marecha camels, five SNPs at q<0.01 and 96 at q<0.05 were significantly associated with the weight traits considered, while three (q<0.01) and seven (q<0.05) SNP associations were identified for Lassi camels. Several candidate genes harbouring these SNP were discovered.
These results will help to better understand the genetic architecture of growth including how these genes are expressed at different phases of their life. This will serve to lay the foundations for applied breeding programs of camels by allowing the genetic selection of superior animals.
生长性能和与生长相关的性状对家畜生产力有至关重要的影响。本全基因组关联研究（GWAS）在巴基斯坦单峰骆驼中开展，旨在识别与特定骆驼年龄生长相关的单核苷酸多态性（SNP），并针对选定的SNP详细研究其效应如何随骆驼年龄增长而变化。这是该地区首次对单峰骆驼进行的GWAS研究。
本研究选取了两个巴基斯坦品种，即马雷查（Marecha）和拉西（Lassi）。采用基因分型测序方法，共识别出65,644个SNP。对于GWAS，利用基于模型的生长曲线分析，分析了包括出生体重、断奶体重以及骆驼1、2、4和6岁时体重等多个体重性状的体重记录数据。使用包含SNP基因型固定效应以及性别的线性混合模型，对特定年龄的体重数据进行分析。
基于错误发现控制的q值方法，对于马雷查骆驼，q<0.01时5个SNP和q<0.05时96个SNP与所考虑的体重性状显著相关，而对于拉西骆驼，分别识别出3个（q<0.01）和7个（q<0.05）SNP关联。发现了包含这些SNP的几个候选基因。
这些结果将有助于更好地理解生长的遗传结构，包括这些基因在其生命不同阶段的表达情况。这将为骆驼的应用育种计划奠定基础，从而能够对优良动物进行遗传选择。
