Selection on Nuclear Genes in a Pinus Phylogeny

• In this study, we investigate natural selection in a pine phylogeny. DNA sequences from 18 nuclear genes were used toconstruct a very well-supported species tree including 10 pine species. This tree is in complete agreement witha previously reported supertree constructed from morphological and molecular data, but there are discrepancies withprevious chloroplast phylogenies within the section Pinus. A significant difference in evolutionary rate between Piceaand Pinus was found, which could potentially indicate a lower mutation rate in Picea, but other scenarios are alsopossible. Several approaches were used to study selection patterns in a set of 21 nuclear genes in pines and in some casesin Picea and Pseudotsuga. The overall pattern suggests efficient purifying selection resulting in low branch-specific dn/dsratios with an average of 0.22, which is similar to other higher plants. Evidence for purifying selection was common andfound on at least 55% of the branches. Evidence of positive selection at several sites was found in a phytocyanin homologand significant differences in dn/ds among the branches in the gene tree in dehydrin 1. Several genes suitable for furtherphylogenetic analysis at various levels of divergence were identified.  

Ämnesord

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

selection

phylogeny

pine

nuclear genes

sequence polymorphisms

gene trees

Biology

Biologi

Genetics

Genetik

Publikations- och innehållstyp

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