Exterior and morphology of dogs

The mutation mstn was identified in the Whippet breed, which causes a doubling of muscle mass. The standard Whippet is a medium-sized dog with an average weight of about 9 kg, a slender build, a long neck, a small head and a pointed muzzle. Dogs with double musculature are homozygous for the mstn mutation and appear as strongly muscled dogs with broad chest and highly muscled legs and neck. There were no reported health problems related to muscle mass in these dogs, with the exception of muscle spasms in the shoulder and thigh, most of which were noticeably undershot.

Heterozygous Whippets (genotype: N / mstn) carrying one copy of the mutant gene appear more muscular than standard whippets (genotype N / N), but are able to achieve better results when racing. However, they cannot be phenotypically distinguished from wild-type dogs,and the only way to identify a carrier is through genetic testing.