Document: ERI-3-25-5

Patterns of variability in purple needlegrass: Do genetic markers and quantitative traits tell the same story?

KNAPP, E.* and K.RICE

University of California Davis ¹

Abstract:
Understanding the spatial scales over which populations are locally adapted is an important issue for habitat restoration. Patterns of adaptive genetic variation are typically evaluated using common garden studies and reciprocal transplant experiments. To make conservation recommendations, many authors have instead relied on molecular genetic markers, since these data are typically more rapidly and easily obtained. However, evolutionary theory predicts that patterns of genetic marker and adaptive genetic variability may not be comparable unless the molecular markers are linked to genes controlling these traits. We evaluated both quantitative trait and isozyme variation among 10 native populations of purple needlegrass, Nassella pulchra, a species commonly translocated for use in restoration plantings, in order to investigate the correspondence between both types of data. We also regressed these genetic distance measures against estimates of geographic distance and climatic distance. Patterns of variation detected by isozymes and quantitative traits were not congruent. Quantitative trait variation was associated with climatic variables but isozyme variation was not. Isozyme variation was more strongly associated with geographic distance between populations. Cluster analysis of population similarity demonstrated very different patterns depending on the type of data used. Recommendations for population translocation in this species should not be based solely on neutral or nearly neutral genetic markers.

Keywords: isozyme, quantitative trait, genetic variation, population differentiation

This abstract is being presented at: 8:45 AM in session:
Symposium # 26: Conservation of Ecologically Important Variation: Comparing Molecular Markers and Ecological Traits.