Evolution of the Genotype-to-Phenotype Map and the Cost of Pleiotropy in Mammals
Arthur Porto, Ryan Schmelter, John L. VandeBerg, Gabriel Marroig, James M. Cheverud
GENETICS Early online October 26, 2016; DOI: 10.1534/genetics.116.189431
Source/Fonte: Interface Focus
Evolutionary studies have long emphasized that the genetic architecture of traits holds important microevolutionary consequences. Yet, studies comparing the genetic architecture of traits across species are rare, and discussions of the evolution of genetic systems are made on theoretical arguments rather than on empirical evidence. Here, we compared the genetic architecture of cranial traits in two different mammalian model organisms, the gray short-tailed opossum, Monodelphis domestica, and the laboratory mouse, Mus musculus. We show that both organisms share a highly polygenic genetic architecture for craniofacial traits, with many loci of small effect. However, these two model species differ significantly in the overall degree of pleiotropy of the genotype-to-phenotype map, with opossums presenting a higher average degree of pleiotropy. They also diverge in their degree of genetic modularity, with opossums presenting less modular patterns of genetic association among traits. We argue that such differences highlight the context dependency of gene effects, with developmental systems shaping the variational properties of genetic systems. Finally, we also demonstrate based on the opossum data that current measurements for the relationship between the mutational effect size and the degree of pleiotropy need to be re-evaluated in relation to the importance of the cost of pleiotropy for mammals.
COMPLEXITY GENETIC ARCHITECTURE MARSUPIALS
Received March 18, 2016. Accepted October 18, 2016.
Copyright © 2016, The Genetics Society of America