Individuals of a particular species generally differ from
one another. We are clearly most adept at recognizing members of our own
species, although dog and cat owners will be ready to confirm that their pets
look unique. Differences within species relate to characteristics such as size
and shape but also to colour: it is not only humans that show a wide range of
skin pigmentation. Nevertheless, the cause of the variation in skin colour in
animals has remained largely a matter for conjecture. Recent work in the group
of Christian Schlötterer at the University of Veterinary Medicine, Vienna sheds
light on the topic. The results are published in the online journal PLOS
Genetics and point to a general method for studying variation in natural
populations.