Table1_Genome-wide association analysis reveals 6 copy number variations associated with the number of cervical vertebrae in Pekin ducks.docx

As a critical developmental stage in vertebrates, the vertebral column formation process is under strict control; however, we observed variations in the number of cervical vertebrae in duck populations in our previous study. Here, we further explored the variations in the number of vertebrae in two duck populations: 421 Pekin duck × mallard F2 ducks and 850 Pekin ducks. Using resequencing data of 125 Pekin ducks with different numbers of cervical vertebrae and 352 Pekin duck × mallard F2 ducks with different numbers of thoracic vertebrae, we detected whole-genome copy number variations (CNVs) and implemented a genome-wide association study (GWAS) to identify the genetic variants related to the traits. The findings verified the existence of variations in the number of cervical vertebrae in duck populations. The number of cervical vertebrae in most ducks was 15, while that in a small number of the ducks was 14 or 16. The number of cervical vertebrae had a positive influence on the neck production, and one cervical vertebra addition could increase 11 g or 2 cm of duck neck. Genome-wide CNV association analysis identified six CNVs associated with the number of cervical vertebrae, and the associated CNV regions covered 15 genes which included WNT10A and WNT6. These findings improve our understanding of the variations in the number of vertebrae in ducks and lay a foundation for future duck breeding.

作为脊椎动物的关键发育阶段，脊柱形成过程受到严格调控；但在前期研究中，我们于鸭群中观察到颈椎数量存在变异。本研究进一步探究了两个鸭群的椎骨数量变异：421只北京鸭（Pekin duck）×绿头鸭（mallard）F2代个体，以及850只北京鸭。我们利用125只颈椎数量各异的北京鸭、以及352只胸椎数量各异的北京鸭×绿头鸭F2代个体的重测序数据，检测了全基因组拷贝数变异（copy number variations, CNVs），并开展全基因组关联分析（genome-wide association study, GWAS）以鉴定与该性状相关的遗传变异。研究结果证实了鸭群颈椎数量变异的存在：多数鸭只的颈椎数量为15枚，少数个体为14枚或16枚。颈椎数量对产颈性能具有正向影响，每增加1枚颈椎，可使鸭颈增重11克或增长2厘米。全基因组CNV关联分析共鉴定出6个与颈椎数量相关的CNV，相关CNV区域覆盖15个基因，其中包含WNT10A与WNT6。本研究结果加深了我们对鸭类椎骨数量变异的认知，为后续鸭类育种工作奠定了基础。