Abstracts (first author)
Genetic evidence for mosaic brain evolution in mammals
The mammalian brain consists of distinct parts that serve different functions. It has been argued that evolution of the mammalian brain is constrained by developmental programs (concerted evolution) and that different brain parts are not free to respond individually to selection and evolve independent of other parts as predicted by a mosaic scenario of brain evolution. We test these hypotheses using a quantitative genetic approach involving over 10,000 mice and identify independent loci for size variation in seven key parts of the brain. We further demonstrate that brain parts show low or no phenotypic correlation, as is predicted by a mosaic scenario. We also demonstrate that variation in brain size is independently regulated from body size. The allometric relations seen at higher phylogenetic levels are thus unlikely to be the product of strong developmental constraints.