Data from: Positive selection within a diatom species acts on putative protein interactions and transcriptional regulation

Diatoms are the most species-rich group of micro-algae, and their
contribution to marine primary production is important on a global scale.
Diatoms can form dense blooms through rapid asexual reproduction;
mutations acquired and propagated during blooms likely provide the
genetic, and thus phenotypic, variability upon which natural selection may
act. Positive selection was tested using genome and transcriptome-wide
pair-wise comparisons of homologs in three genera of diatoms,
Pseudo-nitzschia, Ditylum, and Thalassiosira that represent decreasing
phylogenetic distances. The signal of positive selection was greatest
between two strains of T. pseudonana. Further testing, among seven strains
of T. pseudonana, yielded 809 candidate genes of positive selection, which
are 7 % of the protein coding genes. Orphan genes and genes encoding
protein binding domains and transcriptional regulators were enriched
within the set of positively selected genes relative to the genome as a
whole. Positively selected genes were linked to the potential selective
pressures of nutrient limitation and sea surface temperature based on
analysis of gene expression profiles and identification of positively
selected genes in subsets of strains from locations with similar
environmental conditions. The identification of positively selected genes
presents an opportunity to test new hypotheses in natural populations and
the laboratory that integrate selected genotypes in T. pseudonana with
their associated phenotypes and selective forces.