Extreme plasticity of reproductive state in a female rodent.

Successful sexual reproduction relies on the coordination of multiple biological systems, yet traditional concepts of biological sex often ignore the natural plasticity in morphology and physiology underlying sex. Most female mammals develop a patent (i.e.

Derived variants at six genes explain nearly half of size reduction in dog breeds.

Selective breeding of dogs by humans has generated extraordinary diversity in body size. A number of multibreed analyses have been undertaken to identify the genetic basis of this diversity. We analyzed four loci discovered in a previous genome-wide association study that used 60,968 SNPs to identify size-associated genomic intervals, which were too large to assign causative roles to genes.

Four loci explain 83% of size variation in the horse.

Horse body size varies greatly due to intense selection within each breed. American Miniatures are less than one meter tall at the withers while Shires and Percherons can exceed two meters. The genetic basis for this variation is not known.