A genomic duplication in Arabidopsis thaliana contains a sequence similar to the human gene coding for SAP130

The Arabidopsis thaliana gene orthologue to human SAP130 is contained in a perfect genomic duplication of 4.3 kb. The 1 217-aa AtSAP130 protein is 73 % similar to the human gene that is also present in the Caenorhabditis elegans, Drosophila melanogaster and Sacharomyces pombe genomes. The duplicated sequence includes the coding region, two introns, a 32-bp segment in the 5’ non-coding region and 420 bp of 3’ non-coding region that contains an intron. Sequence homology with ESTs suggests that at least one of the gene copies is transcribed. The presence of the 4.5-kb inverted duplicated sequence has been verified in thirteen ecotypes of A. thaliana. Size variation was detected relative to the Columbia ecotype and corresponds to the deletion of a 3’ non-coding region that is flanked by a 110-bp tandem repeat. The AtSAP130 duplication appears to be a recent event in the Arabidopsis species evolution.