Bahbahani Hussain
Department of Biological Sciences, Faculty of Science, Kuwait University, Sh. Sabah Al-Salem Campus, Kuwait.
Heliyon. 2024 Jul 9;10(14):e34343. doi: 10.1016/j.heliyon.2024.e34343. eCollection 2024 Jul 30.
The genome of dromedary camels has been subjected to various evolutionary forces, such as genetic admixture, natural positive selection, and epistatic selection. These forces are considered as main factors associated with the formation of long-range linkage disequilibrium (LRLD) events. We have analyzed whole-genome data of 56 dromedary camel samples from different geographical regions across the Arabian Peninsula for two main purposes: first, to assess the level of linkage disequilibrium, and second, to identify autosomal LRLD events. The analysis revealed a mean value of 0.25 (±0.028) over the dromedary autosomes, with a continuous decay until reaching a plateau at inter-variant distances >400 kb. A total of 1847 LRLD events were identified within the dromedary autosomes, which harbor 36 prevalent haplotypes. A level of genetic admixture was observed among the dromedary populations analyzed, which might be a source for the observed LRLD events. Four functional interactions were revealed among the genes found within the LRLD events, with some genes overlapping with prevalent haplotypes, indicative of potential epistatic selection. Genes related to renal function, fertility, thermal regulation, bone structure, and insulin regulation were found among the LRLD genes. These genes, along with the defined prevalent haplotypes, can be considered as hotspots for natural positive selection associated with the LRLD distribution on dromedary genomes. In this study, we have for the first time analyzed the genome of dromedary camels for LRLD events possibly influenced by forces including genetic admixture, epistatic and positive selection. The revealed LRLD elements and prevalent haplotypes should be accounted for when designing breeding programmes to conserve the genetic stock of this well-adapted domestic species.
单峰骆驼的基因组受到了各种进化力量的影响，如基因混合、自然正选择和上位性选择。这些力量被认为是与长程连锁不平衡（LRLD）事件形成相关的主要因素。我们分析了来自阿拉伯半岛不同地理区域的56个单峰骆驼样本的全基因组数据，主要有两个目的：第一，评估连锁不平衡水平；第二，识别常染色体LRLD事件。分析显示，单峰骆驼常染色体的平均值为0.25（±0.028），随着变异间距离>400 kb时达到平稳状态，其值持续下降。在单峰骆驼常染色体中总共识别出1847个LRLD事件，这些事件包含36种常见单倍型。在所分析的单峰骆驼种群中观察到了一定程度的基因混合，这可能是观察到的LRLD事件的一个来源。在LRLD事件中发现的基因之间揭示了四种功能相互作用，一些基因与常见单倍型重叠，表明存在潜在的上位性选择。在LRLD基因中发现了与肾功能、生育能力、体温调节、骨骼结构和胰岛素调节相关的基因。这些基因以及定义的常见单倍型可被视为与单峰骆驼基因组上LRLD分布相关的自然正选择热点。在本研究中，我们首次分析了单峰骆驼基因组中的LRLD事件，这些事件可能受到包括基因混合、上位性和正选择等力量的影响。在设计育种计划以保护这种适应性良好的家养物种的遗传资源时，应考虑所揭示的LRLD元件和常见单倍型。
