Translator Disclaimer
1 October 2008 Lifetime Fitness in Two Generations of Ipomopsis Hybrids
Author Affiliations +
Abstract

Various models purporting to explain natural hybrid zones make different assumptions about the fitness of hybrids. One class of models assumes that hybrids have intrinsically low fitness due to genetic incompatibilities, whereas other models allow hybrid fitness to vary across natural environments. We used the intrinsic rate of increase to assess lifetime fitness of hybrids between two species of montane plants Ipomopsis aggregata and Ipomopsis tenuituba planted as seed into multiple field environments. Because fitness is predicted to depend upon genetic composition of the hybrids, we included F1 hybrids, F2 hybrids, and backcrosses in our field tests. The F2 hybrids had female fitness as high, or higher, than expected under an additive model of fitness. These results run counter to any model of hybrid zone dynamics that relies solely on intrinsic nuclear genetic incompatibilities. Instead, we found that selection was environmentally dependent. In this hybrid zone, cytoplasmic effects and genotype-by-environment interactions appear more important in lowering hybrid fitness than do intrinsic genomic incompatibilities between nuclear genes.

Diane R. Campbell, Nickolas M. Waser, George Aldridge, and Carrie A. Wu "Lifetime Fitness in Two Generations of Ipomopsis Hybrids," Evolution 62(10), 2616-2627, (1 October 2008). https://doi.org/10.1111/j.1558-5646.2008.00460.x
Received: 11 March 2008; Accepted: 20 June 2008; Published: 1 October 2008
JOURNAL ARTICLE
12 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top