Article Abstract:
Researchers investigated the power of associative overdominance in creating a correlation between individual heterozygosity and fitness and in maintaining genetic polymorphism at neutral loci. This was done by simulating a diploid model with five chromosomes. Various combinations such as population size, number of crossovers, selection coefficient, and dominance were used. All combination of parameter values resulted in positive regression, even though fitness differences were not large. The link between individual heterozygosity and fitness was clear for recessive mutations. The results showed that associative overdominance could help maintain polymorphisms in small populations.
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Article Abstract:
Plant traits are often phenotypically elastic as they respond to resource levels that vary gradually from one environment to another. Rosette leaf number and flowering data have been measured in recombinant inbred lines of Arabidopsis thaliana grown in continuously varying light intensities. Research data show that genetic variation exists among the recombinant inbred lines for parameters of the reaction norm functions. Underlying quantitative trait loci (QTLs) that affected shape of the reaction norm functions have been mapped.
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Article Abstract:
A computer simulation suggests that mutation rather than selection is more likely to control the polymorphism and evolutionary rate of allozyme proteins. The range of models that can account for the variation in allozyme heterozygosity and genetic distance through type or intensity of selection is fairly narrow, whereas mutation rate can more easily explain the variation through a wider range of models.
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