QTLs for CNS Morphometric Traits

Brain weight is a classic polygenic trait and one that is likely to be influenced during development by the activity of hundreds of genes. Brain weight is also affected by maternal factors and by myriad environmental factors. Many factors that affect body size have important pleiotropic or correlated effects on brain size, making the selectivity of action a critical problem. From the point of view of genetic complexity, it is hard to imagine another morphometric trait that would be more difficult to resolve into individual QTLs. In spite of the difficulties, my collaborator, Dr. Williams has already succeeded in mapping QTLs that selectively affect the weight of the brain.