PT  - JOURNAL ARTICLE
AU  - Srinidhi Varadharajan
AU  - Simen R. Sandve
AU  - Ole K. Tørresen
AU  - Sigbjørn Lien
AU  - Leif Asbjørn Vøllestad
AU  - Sissel Jentoft
AU  - Alexander J. Nederbragt
AU  - Kjetill S. Jakobsen
TI  - The grayling genome reveals selection on gene expression regulation after whole genome duplication
AID  - 10.1101/153270
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 153270
4099  - http://biorxiv.org/content/early/2017/06/22/153270.short
4100  - http://biorxiv.org/content/early/2017/06/22/153270.full
AB  - Whole genome duplication (WGD) has been a major evolutionary driver of increased genomic complexity in vertebrates, yet little is known about how selection operates on the resulting gene duplicates. Here, we present a draft genome assembly of a salmonid species, European grayling (Thymallus thymallus) and use comparative genomics and transcriptomics to understand evolutionary consequences of WGD in the genome of salmonid ancestor ~80 million years ago (Ss4R). We find evidence for lineage-specific rates in rediploidization and that ~60% of the Ss4R ohnologs have experienced different types of non-neutral evolution of tissue-specific gene expression regulation. Distinct selective pressures were associated with tissue type, biological function and selection pressure on protein coding sequence. Finally, our results indicate the role of adaptive divergence of Ss4R duplicates in the evolution of salmonid metabolism and identifies loss of purifying selection on one Ss4R ohnolog encoding a key chloride pump linked to the evolution of anadromy.