Gene duplication and the evolution of plant MADS-box transcription factors.

Since the first MADS-box transcription factor genes were implicated in the establishment of floral organ identity in a couple of model plants, the size and scope of this gene family has begun to be appreciated in a much wider range of species. Over the course of millions of years the number of MADS-box genes in plants has increased to the point that the Arabidopsis genome contains more than 100. The understanding gained from studying the evolution, regulation and function of multiple MADS-box genes in an increasing set of species, makes this large plant transcription factor gene family an ideal subject to study the processes that lead to an increase in gene number and the selective birth, death and repurposing of its component members. Here we will use examples taken from the MADS-box gene family to review what is known about the factors that influence the loss and retention of genes duplicated in different ways and examine the varied fates of the retained genes and their associated biological outcomes.