Nodulation genes amplification model related to gene duplication events in soybean.

  The best, secondary, and other matched homologous gene pairs output by Blast were dotploted by red, blue, and gray colors in this figure, respectively. The Vitis vinifera 19 chromosomes colored by the 7 eudicot ancestral chromosomes according to previous reports (Jaillon et al. 2007). Genomic orthology and outparalogy chromosome regions were identified and distinguished by solid and dashed squares, respectively. Bi-directional arrows link complement correspondence showing likely chromosome breakages during evolution.