Abstract
The goal of this project is to contribute towards the understanding of how genetic architecture (the structure of the mapping from genotype to phenotype) affects the evolution of quantitative traits. According to quantitative genetics theory, the evolution of phenotypic traits depends on the strength of selection and the amount of genetic variation. However, part of this variation maybe constrained by correlations with other traits that are under conflicting selection regimes. In consequence, the ability to respond to selection (evolvability) may be limited, even if a trait has high heritability. However, the extent to which genetic architecture limits phenotypic evolution remains an open question. Likewise, it is unknown whether it affects only evolution on the short time scale and is easily overcome by selection, or if the genetic architecture is an important long-term determinant of the direction of evolution. In this project we aim to answer these questions using two plant species from the family Apiaceae, Daucus carota and Ferula communis, as a model system. If genetic architecture influences the direction of evolution, the differences between populations should conform to the directions of the highest evolvability. Both species are characterized by different distributions and contrasting levels of phenotypic variation. This disparity will be used to test whether our hypothesis can be generalized to organisms with very different patterns of trait divergence. We intend to apply comparative phylogenetic methods based on Ornstein-Uhlenbeck models to verify if the genetic architecture is reflected in the history of the group. We assume that traits should adapt faster to changing conditions if they exhibit high evolvability. These analyses will be done on a dated phylogeny of Daucus (<10 million years) and Ferula (<6 Ma), and on the entire tribe Scandiceae (<35 Ma) to which both genera belong. This will determine the time frame in which the impact of genetic architecture is the most influential. However, phylogenetic comparative methods based on Ornstein-Uhlenbeck models are under-developed both theoretically and practically. Therefore, we also intend to improve existing models.
Marcin Piwczyński
Chair of Ecology and Biogeography, Nicolaus Copernicus University in Toruń, Lwowska 1, PL-87-100 Toruń, Poland.