In our study “Variation in breeding practices and geographic isolation drive subpopulation differentiation, contributing to the loss of genetic diversity within dog breed lineages”, published inCanine Medicine and Genetics, we used commercially obtained genomic data to study subpopulation differentiation in six popular dog breeds, Belgian Shepherd, English Greyhound, Finnish Lapphund, Italian Greyhound, Labrador Retriever and Shetland Sheepdog.

We found strong subpopulation differentiation in all of these breeds, which corresponded either to the geographic origin or the specialized breed lineages within the breeds. While we were expecting to see some differentiation, especially as the populations in some countries are based on a rather small number of founders, it was surprising to see how distinct these subpopulations were genetically and how rapid the genetic differentiation in some breeds had been. For example, the so-called herding lineage of the Finnish Lapphund has differentiated from the companion lineage in mere three decades without any geographic barriers, just driven by diverging kennel preferences.

我们的观察结果既具有实用性，也具有更多哲学上的狗窝实践结果。从定义上讲，育种犬能够实现给定的繁殖理想将导致不必要的变异丧失，并且是所有家养动物繁殖的基础。总的来说，差异化和统一性并不糟糕，但是默认情况下，许多品种都很小，并且有遭受世代相传抑郁症的累积影响的危险。不需要废除专业的血统，但是品种组织应该更积极地将狗在谱系之间​​或密切相关的品种之间混合。例如，虽然维持专业谱系的维护可能是合理的，例如工作品种，但大多数表型分化的品种仅适合我们创造专业的愿望。此外，许多这些专业特征（例如外套或类型）都是隐性的单基因特征。可以从杂合个体的计划穿越，可以在基因检测的帮助下识别出隐性表型。需要记住，狗繁殖是由人为的标准引起的，人造标准的育种理由应进行严格评估，而多样化的育种选择优于狭窄的理想。

与广泛的离散，紧密定义的品种的理想相反，有些品种，例如北欧Spitz或Norrbottenspets，其繁殖试图模仿在野狗中运行的自然选择，可以看作是范式变化的例子在狗窝实践中。这种小型狩猎品种在芬兰通过严格的近交限制维持在芬兰，将每个父亲的幼犬数量限制为30，并有一本开放的螺柱书，并强调狗表演中的狗外观或资格，同时需要进行强制性健康检查以进行繁殖小狗。尽管曾经接近灭绝，但目前是most genetically diverse dog breeds在世界上。

Our study is also an example how commercially obtained genome data can be utilized to provide valuable information on subpopulation differentiation and genetic diversity of dog breeds. Data helps us also to understand the genetic relationships andancestral gene flow among the contemporary dog breeds，通常在品种爱好者中推测。

从更一般的角度来看，人口瓶颈的综合作用和选择对遗传分化的选择令人惊讶。尽管众所周知，但大多数狗都以其惊人的表型变异而繁殖的事实大多在过去的200年中出现了，这也许仍然是进化力量正在行动的不受欢迎的例子。了解狗品种的遗传分化可能会为自然种群的演变提供有趣的见解，例如物种的适应性辐射或来自偏远岛屿栖息地的少数创始人的物种形成。同样，狗繁殖亚群的快速分化伴随着遗传多样性的丧失，强调了栖息地丧失和破碎对濒危物种种群遗传学的影响。相对较少的繁殖个体的狗亚群密切模仿许多濒危物种的空间分散种群的状况。狗还可以提供实用的，受控的模型，以研究濒危种群的遗传营救的影响，并有助于有关转移个体数量和所需遗传差异的设备实践，以实现救援目标。

Directional breeding is a powerful tool, which humans have applied for millennia to sculpt animals and plants alike. However, with power comes the responsibility to not do harm. Our greatest animal companions deserve us to see them in a broader view.