Comparative mapping of the human 9q34 region in Fugu rubripes

Twenty-seven genes have been cloned and mapped in Fugu which have orthologues within the human chromosome 9q34 region. The genes are arranged into five cosmid and BAC contigs which physically map to two different Fugu chromosomes. Considering the gene content of these contigs, it is more probable that a translocation event took place early in the Fugu lineage to split the ancestral 9q34 region onto two chromosomes rather than the alternative hypothesis of a large-scale duplication of the region into two chromosomes with subsequent rapid and dramatic gene loss. There are considerable differences in gene order between the two species, which would appear to be the result of a series of complex chromosome inversions; thus suggesting that there have been no positional constraints on this particular gene set.