Comparison of Borzoi and boxer muzzles: Effects of artificial selection
The boxer muzzle shows one type
of brachycephaly, a foreshortening of the face in
contrast to most other long-faced canids. Boxers, which like
other dog breeds have been subject to artificial selection
for centuries to reinforce desirable show characteristics,
shows two regions of low heterozygosity on Chromosome 1
& 26 that surround genes implicated in
brachycephaly. Strong selection for the short-faced allelic
variants has also fixed adjacent gene regions, a phenomenon
called a "selective sweep".
Figures © 2013 by Sinauer; Text material © 2017 by Steven M. Carr