PUBLICATION
Sequencing and comparative analysis of fugu protocadherin clusters reveal diversity of protocadherin genes among teleosts
- Authors
- Yu, W.P., Yew, K., Rajasegaran, V., and Venkatesh, B.
- ID
- ZDB-PUB-070409-27
- Date
- 2007
- Source
- BMC Evolutionary Biology 7(1): 49 (Journal)
- Registered Authors
- Venkatesh, Byrappa
- Keywords
- none
- MeSH Terms
-
- Animals
- Cadherins/genetics*
- Fish Proteins/genetics*
- Fishes/genetics*
- Gene Conversion
- Genetic Variation*
- Molecular Sequence Data
- Multigene Family*
- Phylogeny
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Takifugu/genetics*
- Zebrafish/genetics
- PubMed
- 17394664 Full text @ BMC Evol. Biol.
Citation
Yu, W.P., Yew, K., Rajasegaran, V., and Venkatesh, B. (2007) Sequencing and comparative analysis of fugu protocadherin clusters reveal diversity of protocadherin genes among teleosts. BMC Evolutionary Biology. 7(1):49.
Abstract
BACKGROUND: The synaptic cell adhesion molecules, protocadherins, are a vertebrate innovation that accompanied the emergence of the neural tube and the elaborate central nervous system. In mammals, the protocadherins are encoded by three closely-linked clusters (alpha, beta and gamma) of tandem genes and are hypothesized to provide a molecular code for specifying the remarkably-diverse neural connections in the central nervous system. Like mammals, the coelacanth, a lobe-finned fish, contains a single protocadherin locus, also arranged into alpha, beta and gamma clusters. Zebrafish, however, possesses two protocadherin loci that contain more than twice the number of genes as the coelacanth, but arranged only into alpha and gamma clusters. To gain further insight into the evolutionary history of protocadherin clusters, we have sequenced and analyzed protocadherin clusters from the compact genome of the pufferfish, Fugu rubripes. RESULTS: Fugu contains two unlinked protocadherin loci, Pcdh1 and Pcdh2, that collectively consist of at least 77 genes. The fugu Pcdh1 locus has been subject to extensive degeneration, resulting in the complete loss of Pcdh1 gamma cluster. The fugu Pcdh genes have undergone lineage-specific regional gene conversion processes that have resulted in a remarkable regional sequence homogenization among paralogs in the same subcluster. Phylogenetic analyses show that most protocadherin genes are orthologous between fugu and zebrafish either individually or as paralog groups. Based on the inferred phylogenetic relationships of fugu and zebrafish genes, we have reconstructed the evolutionary history of protocadherin clusters in the teleost fish lineage. CONCLUSION: Our results demonstrate the exceptional evolutionary dynamism of protocadherin genes in vertebrates in general, and in teleost fishes in particular. Besides the fish-specific whole genome duplication, the evolution of protocadherin genes in teleost fishes is influenced by lineage-specific gene losses, tandem gene duplications and regional sequence homogenization. The dynamic protocadherin clusters might have led to the diversification of neural circuitry among teleosts, and contributed to the behavioral and physiological diversity of teleosts.
Genes / Markers
Expression
Phenotype
Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Fish
Orthology
Engineered Foreign Genes
Mapping