Species demography and the distribution of fitness effects of new deleterious mutations in wild tomatoes (Solanum section Lycopersicon)

点击翻译按钮获取中文摘要

Wild tomato species, native to western South America and the Galapagos Islands, are an evolutionary plant model system. Although wild tomatoes have a relatively recent origin, they exhibit considerable morphological and genetic variation. Using species-wide samples, our first goal is to analyze the divergence process of the tomato clade and estimate the species demography (in particular, of the self-incompatible species). This approach is based on our recent theoretical analyses that sampling schemes can influence genealogical signatures in sequence data even under high levels of migration. The second goal is to use samples collected from local populations to estimate the distribution of fitness effects of deleterious mutations. Since deleterious mutations occur at a genome-wide level, they may affect the site frequency spectrum of polymorphisms and hence have an effect on the demography of local populations. In general, this project will advance our understanding of the effects of sampling on demographic inferences in subdivided nonequilibrium populations.