Abstract Detail

Nº613/1820 - A comparative look at genome fractionation in pteridophytes
Format: ORAL
Authors
Sylvia P. Kinosian1, Fay-Wei Li2, Michael S. Barker1
Affiliations
1 Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, USA 2 Boyce Thompson Institute, Ithaca, NY, USA
Abstract
Genetic variation created by whole genome duplication (WGD) events can provide beneficial genetic variation for evolution to act upon. However, polyploid genomes comprise many, sometimes unnecessary, duplicated genes. The loss of these duplicates is part of the process of diploidization. One mechanism of diploidization is fractionation, where genes are lost or silenced in one or both homoeologs. Fractionation structurally and functionally alters the genome as only a subset of duplicated genes is retained. This affects the amount of genetic variation present following diploidization, influencing how a lineage will be able to evolve. Despite its evolutionary importance, little is known about how fractionation occurs in different lineages of land plants, particularly in ferns and lycophytes (pteridophytes). In angiosperms, fractionation is thought to proceed quickly, mainly by gene loss. Previous work suggests that genes may be silenced rather than lost in pteridophyte genomes, and chromosomes are retained following WGD. We use newly available published genome sequences for ferns and lycophytes to examine how genome fractionation may be occurring. We find that pteridophyte genomes may fractionate relatively rapidly following WGD, but chromosome order and collinearity are preserved. Including pteridophytes, for the first time, in comparative work on fractionation is a key step to better understanding genome evolution in land plants.