Fractionation of synteny in a genomic region containing tandemly duplicated genes across Glycine max, Medicago truncatula, and Arabidopsis thaliana

Extended comparison of gene sequences found on homeologous soybean Bacterial Artificial Chromosomes to Medicago truncatula and Arabidopsis thaliana genomic sequences demonstrated a network of synteny within conserved regions interrupted by gene addition and/or deletions. Consolidation of gene order among all 3 species provides a picture of ancestral gene order. The observation supports a genome history of fractionation resulting from gene loss/addition and rearrangement. In all 3 species, clusters of N-hydroxycinnamoyl/benzoyltransferase genes were identified in tandemly duplicated clusters. Parsimony-based gene trees suggest that the genes within the arrays have independently undergone tandem duplication in each species.