Submitted to: Molecular Phylogenetics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/1996
Publication Date: N/A
Citation: Interpretive Summary: Over millennia,species are thought to evolve into other species; and often begin to look very different from each other, even though they may be very closely related. Sometimes it is necessary to look at a 'snapshot' of a small piece of hereditary material (DNA) to determine how closely related they are. In this research the authors used a gene involved in packaging and storing of other genes to compare evolutionary relationships among legumes (soybean relatives). They found that this gene was more informative than any other gene tested for identifying relatives of soybean. This will help breeders determine the best possible crosses to make between species, and can tell geneticists and molecular biologists where to look for genes for engineering new and modified traits.
Technical Abstract: Histone H3 loci form a large multigene family in most plant species. In Glycine, some of these loci possess introns, whose sequences may provide characters for assessing phylogenetic relationships among closely related species of the genus. Phylogenetic analyses of two closely related H3-B loci revealed a complex evolutionary pattern, producing trees from which species relationships could not be inferred readily. The single H3-D locus, in contrast, provided data suitable for the construction of gene trees whose topologies were sufficiently similar to other hypotheses of relationships within subgenus Glycine to give confidence that evolution at this locus is tracing species phylogenies. H3-D topologies identified several of the same groupings found in previous studies of the chloroplast genome. However, histone H3-D and chloroplast genome data sets were in other respects incongruent, as revealed both by topological differences and numerical measures of congruence. The principal difference involved G. falcata, whose chloroplast genome belongs to one of the three strongly supported clades in the subgenus, but whose histone H3-D allele was sister to those of the remaining members of the subgenus. The H3-D topology is more in keeping with the morphologically, ecologically, and genetically divergent nature of this species. The H3-D locus appears to be a useful source of phylogenetic characters for interspecific studies in Glycine, providing resolution among taxa whose relationships were unresolved in previous studies.