Expression Divergence Is Correlated with Sequence Evolution but Not Positive Selection in Conifers

• DOI: 10.1093/molbev/msw032
• Publication Date: 2016-02-15T01:19:04Z
• Authors: Kathryn A. Hodgins; Sam Yeaman; Kristin A. Nurkowski; Loren H. Rieseberg; Sally N. Aitken
• Keywords: Directional selection; Divergence (linguistics); Adaptive Evolution; Balancing selection; Negative selection

The evolutionary and genomic determinants of sequence evolution in conifers are poorly understood, previous studies have found only limited evidence for positive selection. Using RNAseq data, we compared gene expression profiles to patterns divergence polymorphism 44 seedlings lodgepole pine (Pinus contorta) 39 interior spruce (Picea glauca × engelmannii) elucidate the forces that shape their genomes plastic responses abiotic stress. We rapidly diverging genes tend greater divergence, lower levels, reduced levels synonymous site diversity, longer proteins than slowly genes. Similar were identified untranslated regions, but with some exceptions. low had a larger fraction nearly neutral sites, suggesting primary role negative selection determining association between rate level. There was differences among divergent versus conserved supporting relaxed species. Finally, small number showed site-specific using data alone. However, estimates proportion sites fixed by (α) range other plant species large effective population sizes relatively high rates adaptive conifers.