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NUCLEAR AND CYTOPLASMIC CONTRIBUTIONS TO INTRASPECIFIC DIVERGENCE IN AN ANNUAL LEGUME
Author(s) -
Galloway Laura F.,
Fenster Charles B.
Publication year - 2001
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.0014-3820.2001.tb00783.x
Subject(s) - biology , intraspecific competition , divergence (linguistics) , evolutionary biology , legume , ecology , philosophy , linguistics
The genetic architecture of trait differentiation was evaluated between two ecologically distinct populations of Chamaecrista fasciculata . Individuals from Maryland and Illinois populations were crossed to create 10 types of seed: Maryland and Illinois parents, reciprocal F 1 and F 2 hybrids, and backcrosses to Maryland and to Illinois on reciprocal F 1 hybrids. Reciprocal crosses created hybrid generation seeds with both Maryland and Illinois cytoplasmic backgrounds. Experimental individuals were grown in a common garden near the site of the Maryland population. In the garden, plants from the Illinois population flowered, set fruit, and died earlier than those from Maryland, likely reflecting adaptations to differences in growing season length between the two populations. Although reproductive components at the flower and whole plant level differed between the two populations, reproductive output as measured by fruit and seed production was similar. Cytoplasmic genes had a subtle but pervasive effect on population differentiation; hybrids with Maryland cytoplasm were significantly differentiated from those with Illinois cytoplasm when all characters were evaluated jointly. The nuclear genetic architecture of population differentiation was evaluated with joint scaling tests. Depending on the trait, both additive and nonadditive genetic effects contributed to population differentiation. Intraspecific genetic differentiation in this wild plant species appears to reflect a complex genetic architecture that includes the contribution of additive, dominance, and epistatic components in addition to subtle cytoplasmic effects.