For example, Rossberg et al. found that one of the five genes on tomato chromosome 7, gene D , which has similarity to WRKY transcription factors, has numerous homologs in other regions of the Arabidopsis genome that were not found to be colinear with the segment identified on Arabidopsis chromosome 1. Thus, analyses of microsynteny also may help to characterize rapidly evolving gene families. Analyses of many different eukaryotic genomes have revealed that polyploidization and gene duplication are widespread phenomena among eukaryotes. A number of simple diploid genomes, including those of yeast and Arabidopsis, appear to be derived from ancient polyploids. The work of Rossberg et al. provides additional evidence for this hypothesis.
Polyploidy is particularly widespread among extant plant species relative to other eukaryotes.
Comparative genomics may begin to provide answers regarding the evolution and maintenance of the various states of ploidy observed among plants and other eukaryotes. Comparative genome analysis reveals extensive conservation of genome organisation for Arabidopsis thaliana and Capsella rubella . Analysis of the genome sequence of the flowering plant Arabidopsis thaliana . Se-quencing the rice genome. Genome duplication in Arabidopsis and synteny between soybean and Arabidopsis .