 |
Dr. Jeff Doyle |
As more has been learned about the genomes of plants and animals, it has become increasingly clear that many, including the human genome, have experienced one or more cycles of doubling (polyploidy). In plants this has been recognized for a long time, with Arabidopsis and major crops such as maize, wheat, and soybean being only a few examples of the 70% or more of flowering plants (and even larger numbers of ferns) that are known to be polyploid.
Many polyploids originate by hybridization and doubling involving distinct diploid species. Major projects in the lab involve identifying the genomes of polyploids and tracing their origins back to living or extinct diploid species. Polyploids formed within the last 100,000 years, such as the perennial relatives of the cultivated soybean, have genes that have diverged little if at all from those of the diploid progenitors, making this job relatively straightforward. Other projects in the lab include similar studies on other groups of plants, including Johnsongrass (a weedy polyploid relative of cultivated sorghum) and tef, a polyploid grass crop that is of considerable importance in Ethiopia (but nowhere else in the world!). Older events are obscured by genome divergence, including gene loss, structural rearrangements, and individual gene duplications. The soybean genome shows evidence of polyploid events that took place around 15 and 40 million years ago. The older of these may be shared with other members of the legume family, and we are using gene phylogenies to test that hypothesis. We are also studying the evolution of genome structure and genome expression in these and other polyploids.
For more information about the Doyle lab, please visit the Plant Biology webpage.