Adapting to a Duplicated Genome

University Of Georgia Research Foundation Inc, Athens GA

Investigators

Abstract

Intellectual Merit. Higher organisms occasionally form aberrant individuals with their entire genetic blueprint doubled relative to that of their parents. While the vast majority of these individuals quickly go extinct, in exceedingly rare cases such "genome duplications" give rise to new lineages that appear to realize numerous advantages resulting from having "spare" copies of each gene. Across hundreds of millions of years of evolution, these rare "success stories" collectively are one of the most important mechanisms by which new genes and new functions evolve. Flowering plants (angiosperms) are more tolerant of genome duplication than most taxa - virtually all have experienced genome duplication at least once and sometimes 3-4 times in the past 150-200 million years, and many neo-polyploids formed in the past 1-2 million years are known including many major crops. With the sequences of a growing number of angiosperm genomes now available, the investigators have identified a population of genes that are distinctive in having (a) higher-than average rates of loss for one but not both member(s) of duplicate pairs, (b) convergent fates across multiple independent duplication events within and/or among lineages, and (c) a higher-than-random degree of correlated gene expression. Herein, the investigators will begin empirical tests of fitness effects associated with both the general population of these "duplication-resistant" genes and specific members, seeking genetic probes into pathways and functions contributing to adaptation of a genome to the duplicated state. Broader Impacts. The experimental facility of Arabidopsis will expedite analysis of some of the most important evolutionary forces shaping eukaryotic genomes, and in particular underlying the biodiversity that enables angiosperms to provide many ecosystem services including most of the worlds food, feed, and fiber. Better understanding of adaptation by a lineage to genome duplication is not only of fundamental interest but may also have practical applications, either directly by improving productivity of polyploid crops, or indirectly by mitigating obstacles to wider use of naturally-occurring germplasm resources in crop improvement. This research is closely tied to the education of students and the public, providing training opportunities at both pre- and postgraduate levels, and contributing to development and implementation of research-based educational materials to improve achievement, comprehension and mastery of scientific concepts by middle and high school students, also building the nucleus for a "teachers teach teachers" program. This project is co-funded by the Arabidopsis 2010 Project.