Symposium II: Adapting to a Dynamic Environment

Abs # 20002: The adaptive evolution of developmental plasticity in natural seasonal environments

Presenter:	Schmitt, Johanna , Johanna_Schmitt@brown.edu
Authors	Schmitt, Johanna  (A)   Stinchcombe, John  (A)   Korves, Tonia  (A)   Weinig, Cynthia  (B)   Purugganan, Michael  (C)
Affiliations:	(A): Ecology and Evolutionary Biology, Brown University (B): Plant Biology, University of Minnesota (C): Genetics, North Carolina State University
Web Site:	http://www.brown.edu/Departments/EEB/faculty/Schmitt.html

Natural populations of Arabidopsis thaliana experience remarkable seasonal environmental heterogeneity. For example, certain New England populations are polymorphic in life history, with fall annual, winter annual, and spring annual cohorts exposed to different climatic conditions. In contrast, populations where winters are mild and summers harsh, such as the southern U.S., exhibit a fixed winter annual strategy. Thus, plants are exposed to different climatic environments and different natural selective pressures on developmental and life history traits both among seasonal cohorts within populations and on a larger geographical scale. QTL mapping in replicate field experiments with recombinant inbred lines planted in spring and fall in natural environments in Rhode Island and North Carolina reveals remarkable seasonal and geographic variation in the genetic control of important life history traits such as flowering time. Moreover, natural selection at specific loci varies between sites and seasons. In addition, natural ecotypic variation in developmental, architectural, and life history traits expressed under natural conditions is statistically associated with allelic variation in candidate genes involved in photoreception and the transition to flowering. Allelic variation at candidate loci is also associated with overwinter mortality, suggesting that this variation may be under selection in natural seasonal environments.