Abstract Detail

Genetics Section

Oakley, Christopher G. [1].

Patterns of heterosis in natural populations of Arabidopsis.

Genetic variation in natural plant populations is subject to the stochastic force of genetic drift, which is caused by a number of factors, including spatial population structure, a history of population bottlenecks, and a selfing mating system. Drift will act to reduce quantitative genetic variation, which provides the raw material for adaptive evolution, and lead to the fixation of partly recessive deleterious mutations. One useful tool for investigating the role of drift in natural populations is heterosis, the increase in fitness of progeny derived from interpopulation outcrossing, caused by the masking of deleterious mutations in the heterozygous state. We investigated patterns of heterosis in a field common garden experiment in Sweden using progeny from crosses between 15 unique population pairs (spanning a range of geographic distances) of Arabidopsis thaliana from Scandinavia. A. thaliana is a selfing annual, and several lines of evidence indicate a potential role for genetic drift in shaping genetic variation underlying fitness, particularly at the northern edge of its native geographic range. We found significant heterosis in 11 of 15 pairs with an average magnitude of 45% (range = 18-109), and examine how the magnitude of heterosis varies as a function of geographic distance, latitude, and genome size. These findings suggest a common role for genetic drift in shaping genetic variation related to fitness in nature.

1 - Michigan State University, Plant Biology, 612 Wilson Road, E Lansing, MI, 48824-1312, USA

Keywords:
Heterosis
Genetic drift
Population bottleneck
Adaptive constrait
Genetic rescue
Arabidopsis.

Presentation Type: Oral Paper:Papers for Sections
Session: 6
Location: Salon 15/16/The Shaw Conference Centre
Date: Monday, July 27th, 2015
Time: 8:45 AM
Number: 6004
Abstract ID:149
Candidate for Awards:Margaret Menzel Award