Plant & Animal Genomes XV Conference

January 13-17, 2007
Town & Country Convention Center
San Diego, CA

Identifying The Targets Of Selection During Sunflower Domestication

Mark A Chapman , Catherine H Pashley , John M Burke

  University of Georgia, Dept of Plant Biology, Athens, GA, 30602

The analysis of population genetic data allows for the identification of genes that have been the target of past selection, and recent years have seen the development of both the molecular tools necessary for performing large-scale screens for the so-called ‘signature of selection’ and the necessary statistical approaches for interpreting the resulting data. We are using these tools to analyze the domestication of sunflower (Helianthus annuus L.) and to investigate the molecular basis of agronomically important traits. We are screening SSR-bearing ESTs in a panel of 48 sunflower populations (24 wild, 8 primitive landraces and 16 improved breeding lines) to assess patterns and levels of variation and to identify genes which have experienced a drop in diversity much greater than expected due to the domestication bottleneck, and hence have potentially been under strong human selection. One advantage of our study over similar screens in other crops is that we can separate the effects of selection during domestication and selection during improvement. We have identified 24 strong candidate genes for human-aided selection (13 during domestication and 11 during improvement) and are carrying out genetic mapping and sequencing in an effort to determine the function of these genes and how they may be related to the phenotypic differences observed between wild and cultivated sunflower.