Plant & Animal Genomes XIII Conference Plant & Animal Genomes XIII ConferenceJanuary 15-19, 2005
Town & Country Convention Center
San Diego, CA
Sutada Mungpakdee , Daniel Chourrout , Hee-Chan Seo
Genome duplication is a far rare event among animals, but it did occur in teleosts and amphibians. Salmonid fish are a good example of tetraploid species that have experienced a more recent duplication (about 25-100 Mya ago). With the intention to address issues such as genome organisation and genetic redundancy in Atlantic salmon, we studied the Hox clusters. Hox clusters are very well conserved in all vertebrates; they are organized in clusters with up to 13 genes in each cluster in vertebrates have 4 Hox clusters whereas tetraploid-like organisms have 7 or more. From the survey based on 1500 PCR-clones originated from one animal, we found 55 different Hox genes in protein level (versus 48 genes in zebrafish). Further identification and characterization were done with PCR genome-walking and BAC clone analysis. We have screened a high quality Atlantic salmon BAC library with various gene-specific probes. The library contains over 320,000 clones (18x coverage) and was available through the SGP (salmon genome project). Combined with the HindIII fingerprinting analysis of this BAC library from the GRASP (genome research on Atlantic salmon project), we have thus far found 12 Hox clusters including 4 HoxC clusters. Full sequencing of BAC clones that contain Hox clusters reveals that the structure and sequence of salmon Hox clusters are in overall similar to those of other teleosts, but some notable differences are also found. Our results shows that Atlantic salmon has undergone one more round of genome duplication that may be specific to salmonids.