Genome duplication, subfunction partitioning, and lineage divergence:Sox9in stickleback and zebrafish

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Abstract
Teleosts are the most species‐rich group of vertebrates, and a genome duplication (tetraploidization) event in ray‐fin fish appears to have preceded this remarkable explosion of biodiversity. What is the relationship of the ray‐fin genome duplication to the teleost radiation? Genome duplication may have facilitated lineage divergence by partitioning different ancestral gene subfunctions among co‐orthologs of tetrapod genes in different teleost lineages. To test this hypothesis, we investigated gene expression patterns for Sox9 gene duplicates in stickleback and zebrafish, teleosts whose lineages diverged early in Euteleost evolution. Most expression domains appear to have been partitioned between Sox9a and Sox9b before the divergence of stickleback and zebrafish lineages, but some ancestral expression domains were distributed differentially in each lineage. We conclude that some gene subfunctions, as represented by lineage‐specific expression domains, may have assorted differently in separate lineages and that these may have contributed to lineage diversification during teleost evolution. Developmental Dynamics, 2003.
Funding Information
  • National Institutes of Health (R01RR10715, 5 F32 GM020892)
  • National Science Foundation (IBN 0236239, IBN 9728587)
  • NSF IGERT (DGE 9972830)