%0 Journal Article
%T Rates of evolution in stress-related genes are associated with habitat preference in two Cardamine lineages
%A Lino Ometto
%A Mingai Li
%A Luisa Bresadola
%A Claudio Varotto
%J BMC Evolutionary Biology
%D 2012
%I BioMed Central
%R 10.1186/1471-2148-12-7
%X High-throughput sequencing was used to obtain gene sequences from C. resedifolia and C. impatiens. Using the available A. thaliana gene sequences and annotation, we identified nearly 3,000 triplets of putative orthologues, including genes involved in cold response, photosynthesis or in general stress responses. By comparing estimated rates of molecular substitution, codon usage, and gene expression in these species with those of Arabidopsis, we were able to evaluate the role of positive and relaxed selection in driving the evolution of Cardamine genes. Our analyses revealed a statistically significant higher rate of molecular substitution in C. resedifolia than in C. impatiens, compatible with more efficient positive selection in the former. Conversely, the genome-wide level of selective pressure is compatible with more relaxed selection in C. impatiens. Moreover, levels of selective pressure were heterogeneous between functional classes and between species, with cold responsive genes evolving particularly fast in C. resedifolia, but not in C. impatiens.Overall, our comparative genomic analyses revealed that differences in effective population size might contribute to the differences in the rate of protein evolution and in the levels of selective pressure between the C. impatiens and C. resedifolia lineages. The within-species analyses also revealed evolutionary patterns associated with habitat preference of two Cardamine species. We conclude that the selective pressures associated with the habitats typical of C. resedifolia may have caused the rapid evolution of genes involved in cold response.Organisms adapt to different habitats through natural selection, which favors the fixation of alleles that increase the fitness of the individual that bears them. However, it is quite difficult to identify the locus/loci targeted by selection. One reason is that the number of loci involved in a particular adaptation and their phenotypic effects vary depending on the genetic a
%K Molecular evolution
%K 454 next generation sequencing
%K adaptive traits
%K habitat preference
%K Cardamine
%U http://www.biomedcentral.com/1471-2148/12/7