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Population divergence of genetic (co)variance matrices in a subdivided plant species, Brassica cretica

Widén, Björn LU ; Andersson, Stefan LU ; Rao, G Y and Widén, Marie LU (2002) In Journal of Evolutionary Biology 15(6). p.961-970
Abstract
The present study of Brassica cretica had two objectives. First, we compared estimates of population structure (Q(st)) for seven phenotypic characters with the corresponding measures for allozyme markers (F-st) to evaluate the supposition that genetic drift is a major determinant of the evolutionary history of this species. Secondly, we compared the genetic (co) variance (G) matrices of five populations to examine whether a long history of population isolation is associated with large, consistent differences in the genetic (co) variance structure. Differences between estimates of Fst and Qst were too small to be declared significant, indicating that stochastic processes have played a major role in the structuring of quantitative variation... (More)
The present study of Brassica cretica had two objectives. First, we compared estimates of population structure (Q(st)) for seven phenotypic characters with the corresponding measures for allozyme markers (F-st) to evaluate the supposition that genetic drift is a major determinant of the evolutionary history of this species. Secondly, we compared the genetic (co) variance (G) matrices of five populations to examine whether a long history of population isolation is associated with large, consistent differences in the genetic (co) variance structure. Differences between estimates of Fst and Qst were too small to be declared significant, indicating that stochastic processes have played a major role in the structuring of quantitative variation in this species. Comparison of populations using the common principal component (CPC) method rejected the hypothesis that the G matrices differed by a simple constant of proportionality: most of the variation involved principal component structure rather than the eigenvalues. However, there was strong evidence for proportionality in comparisons using the method of percentage reduction in mean-square error (MSE), at least when characters with unusually high (co) variance estimates were included in the analyses. Although the CPC and MSE methods provide different, but complementary, views of G matrix variation, we urge caution in the use of proportionality as an indicator of whether genetic drift is responsible for divergence in the G matrix. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Evolutionary Biology
volume
15
issue
6
pages
961 - 970
publisher
John Wiley & Sons
external identifiers
  • wos:000178853600008
  • scopus:0036842632
ISSN
1420-9101
DOI
10.1046/j.1420-9101.2002.00465.x
language
English
LU publication?
yes
id
52e7d530-57ca-4de5-b2c7-8b5ad08f6120 (old id 147152)
date added to LUP
2007-07-03 09:56:22
date last changed
2017-01-01 04:57:13
@article{52e7d530-57ca-4de5-b2c7-8b5ad08f6120,
  abstract     = {The present study of Brassica cretica had two objectives. First, we compared estimates of population structure (Q(st)) for seven phenotypic characters with the corresponding measures for allozyme markers (F-st) to evaluate the supposition that genetic drift is a major determinant of the evolutionary history of this species. Secondly, we compared the genetic (co) variance (G) matrices of five populations to examine whether a long history of population isolation is associated with large, consistent differences in the genetic (co) variance structure. Differences between estimates of Fst and Qst were too small to be declared significant, indicating that stochastic processes have played a major role in the structuring of quantitative variation in this species. Comparison of populations using the common principal component (CPC) method rejected the hypothesis that the G matrices differed by a simple constant of proportionality: most of the variation involved principal component structure rather than the eigenvalues. However, there was strong evidence for proportionality in comparisons using the method of percentage reduction in mean-square error (MSE), at least when characters with unusually high (co) variance estimates were included in the analyses. Although the CPC and MSE methods provide different, but complementary, views of G matrix variation, we urge caution in the use of proportionality as an indicator of whether genetic drift is responsible for divergence in the G matrix.},
  author       = {Widén, Björn and Andersson, Stefan and Rao, G Y and Widén, Marie},
  issn         = {1420-9101},
  language     = {eng},
  number       = {6},
  pages        = {961--970},
  publisher    = {John Wiley & Sons},
  series       = {Journal of Evolutionary Biology},
  title        = {Population divergence of genetic (co)variance matrices in a subdivided plant species, Brassica cretica},
  url          = {http://dx.doi.org/10.1046/j.1420-9101.2002.00465.x},
  volume       = {15},
  year         = {2002},
}