Oral Presentation Society for Molecular Biology and Evolution Conference 2016

Molecular Evolution of Human Breasts (#71)

Reed A Cartwright 1
  1. Arizona State University, Tempe, AZ, United States

The development of mammaries in humans is unique among mammals. During puberty, the breasts of human females enlarge, and no other mammal exhibits similar development before pregnancy and lactation. This phenotype is fixed among humans, evolving some time after our lineage separated from chimpanzees and bonobos, and anthropologists have offered many competing hypotheses about the selective advantage of human breasts. In female mammals, mammary development occurs across several stages: fetal development, puberty, pregnancy, lactation, and post-lactation. We hypothesize that in humans the development of the mammary ductal system during puberty also causes the surrounding tissue to permanently enlarge, producing the unique human phenotype. We have examined the molecular evolution of genes related to mammary development in order to identify candidate genes related to the pubertal enlargement of human breasts. Here we report our progress and discuss the difficulties of studying a non-pathogenic complex phenotype in humans.