PUBLICATION
Comparative genomic analysis of teleost fish bmal genes
- Authors
- Wang, H.
- ID
- ZDB-PUB-081022-22
- Date
- 2009
- Source
- Genetica 136(1): 149-161 (Journal)
- Registered Authors
- Wang, Han
- Keywords
- Circadian clocks, Conserved synteny, Genome duplication, Differential gene loss, Ratio of nonsynonymous to synonymous substitutions and relative evolutionary rates
- MeSH Terms
-
- Fishes/genetics*
- Gene Duplication
- Evolution, Molecular
- Comparative Genomic Hybridization
- RNA Splice Sites
- PubMed
- 18850331 Full text @ Genetica
Abstract
Bmal1 (Brain and muscle ARNT like 1) gene is a key circadian clock gene. Tetrapods also have the second Bmal gene, Bmal2. Fruit fly has only one bmal1/cycle gene. Interrogation of the five teleost fish genome sequences coupled with phylogenetic and splice site analyses found that zebrafish have two bmal1 genes, bmal1a and bmal1b, and bmal2a; Japanese pufferfish (fugu), green spotted pufferfish (tetraodon) and Japanese medaka fish each have two bmal2 genes, bmal2a and bmal2b, and bmal1a; and three-spine stickleback have bmal1a and bmal2b. Syntenic analysis further indicated that zebrafish bmal1a/bmal1b, and fugu, tetraodon and medaka bmal2a/bmal2b are ancient duplicates. Although the dN/dS ratios of these four fish bmal duplicates are all <1, implicating they have been under purifying selection, the Tajima relative rate test showed that fugu, tetraodon and medaka bmal2a/bmal2b have asymmetric evolutionary rates, suggesting that one of these duplicates have been subject to positive selection or relaxed functional constraint. These results support the notion that teleost fish bmal genes were derived from the fish-specific genome duplication (FSGD), divergent resolution following the duplication led to retaining different ancient bmal duplicates in different fishes, which could have shaped the evolution of the complex teleost fish timekeeping mechanisms.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping