The present study focuses on the Belgian Milk Sheep in Flanders (Belgium) and compares its genetic diversity and relationship with the Flemish Sheep, the Friesian Milk Sheep, the French Lacaune dairy sheep and other Northern European breeds. For this study, 94 Belgian Milk Sheep, 23 Flemish Sheep and 22 Friesian Milk Sheep were genotyped with the OvineSNP50 array. In addition, 29 unregistered animals phenotypically similar to Belgian Milk Sheep were genotyped using the 15K ISGC chip. Both Belgian and Friesian Milk Sheep as well as the East Friesian Sheep were found to be less diverse than the other seven breeds included in this study. Genomic inbreeding coefficients based on runs of homozygosity (ROH) were estimated at 14.5, 12.4 and 10.2% for Belgian Milk Sheep, Flemish Sheep and Friesian Milk Sheep respectively. Out of 29 unregistered Belgian Milk Sheep, 28 mapped in the registered Belgian Milk Sheep population. Ancestry analysis, PCA and F_ST calculations showed that Belgian Milk Sheep are more related to Friesian Milk Sheep than to Flemish Sheep, which was contrary to the breeders' expectations. Consequently, breeders may prefer to crossbreed Belgian Milk Sheep with Friesian sheep populations (Friesian Milk Sheep or East Friesian Sheep) in order to increase diversity. This research underlines the usefulness of SNP chip genotyping and ROH analyses for monitoring genetic diversity and studying genetic links in small livestock populations, profiting from internationally available genotypes. As assessment of genetic diversity is vital for long‐term breed survival, these results will aid flockbooks to preserve genetic diversity.

中文翻译：

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利用中等密度SNP基因型揭示比利时奶羊的遗传多样性

本研究的重点是法兰德斯（比利时）的比利时奶羊，并比较其遗传多样性以及与佛兰德羊，弗里斯兰奶羊，法国Lacaune奶羊和其他北欧品种的关系。在这项研究中，使用OvineSNP50阵列对94例比利时奶羊，23只佛兰德羊和22弗里西亚羊进行了基因分型。此外，使用15K ISGC芯片对29个在表型上与比利时奶羊相似的未注册动物进行了基因分型。比利时和弗里斯兰奶羊以及东弗里斯兰羊的多样性都低于本研究中的其他七个品种。比利时奶羊，佛兰芒羊和弗里西亚奶羊基于纯合度（ROH）运行的基因组近交系数分别估计为14.5％，12.4％和10.2％。在29个未注册的比利时奶羊中，有28个映射在已注册的比利时奶羊种群中。祖先分析，PCA和F _ST计算表明，比利时奶羊与弗里斯兰奶羊的关系比佛兰德羊多，这与育种者的预期相反。因此，育种者可能更喜欢将比利时奶羊与弗里斯兰羊种群（弗里斯兰奶羊或东弗里斯兰羊）杂交，以增加多样性。这项研究强调了SNP芯片基因分型和ROH分析在监测遗传多样性和研究小牲畜种群中遗传联系方面的有用性，这得益于国际可用的基因型。由于对遗传多样性的评估对于长期的品种存活至关重要，因此这些结果将有助于羊群保护遗传多样性。