Abstract:
:Linkage disequilibrium between polymorphisms in a natural population may result from various evolutionary forces, including random genetic drift due to sampling of gametes during reproduction, restricted migration between subpopulations in a subdivided population, or epistatic selection. In this report, we present evidence that the majority of significant linkage disequilibria observed in introns of the alcohol dehydrogenase locus (Adh) of Drosophila pseudoobscura are due to epistatic selection maintaining secondary structure of precursor mRNA (pre-mRNA). Based on phylogenetic-comparative analysis and a likelihood approach, we propose secondary structure models of Adh pre-mRNA for the regions of the adult intron and intron 2 where clustering of linkage disequilibria has been observed. Furthermore, we applied the likelihood ratio test to the phylogenetically predicted secondary structure in intron 1. In contrast to the other two structures, polymorphisms associated with the more conserved stem-loop structure of intron 1 are in low frequency, and linkage disequilibria have not been observed. These findings are qualitatively consistent with a model of compensatory fitness interactions. This model assumes that mutations disrupting pairing in a secondary structural element are individually deleterious if they destabilize a functionally important structure; a second "compensatory" mutation, however, may restabilize the structure and restore fitness.
journal_name
Proc Natl Acad Sci U S Aauthors
Kirby DA,Muse SV,Stephan Wdoi
10.1073/pnas.92.20.9047subject
Has Abstractpub_date
1995-09-26 00:00:00pages
9047-51issue
20eissn
0027-8424issn
1091-6490journal_volume
92pub_type
杂志文章abstract::The detrimental effects of elevated intensities of mid-UV radiation (UVB), a result of stratospheric ozone depletion during the austral spring, on the primary producers of the Antarctic marine ecosystem have been well documented. Here we report that natural populations of Antarctic zooplankton also sustain significant...
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更新日期:2004-02-24 00:00:00
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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