Explore a comprehensive lecture on the role of large-effect loci in adaptation, focusing on introduced stickleback populations. Delve into Fisher's model, phenotypic adaptation following freshwater colonization, and the genetic basis of armor differences. Examine how gene discovery is transforming adaptation studies, with emphasis on multiple genes differentiating marine from freshwater populations. Analyze experimental data from F2 and F3 generations, including fitness mapping to the Eda region and its impact on lateral plate morphology. Investigate the two-fold fitness difference between genotypes and changes in allele frequency over time. Compare findings with a second introduced population across multiple generations, and critically evaluate the contribution of large-effect loci to adaptation in nature.
Fitness Maps to a Large-Effect Locus in Introduced Stickleback
Overview
Syllabus
Fitness maps to a large-effect locus in introduced stickleback
Should large-effect loci contribute to adaptation?
Evolution often behaves as though an adaptive peak is being climbed
Fisher's model
Might large-effect loci contribute to adaptation?
Phenotypic adaptation following colonization of freshwater
Genetic basis of armor differences
Gene discovery is transforming the study of adaptation
2. Might large-effect loci contribute to adaptation in nature?
Multiple genes differentiate marine from freshwater populations
Experimental population segregating marine and freshwater alleles
Re-trapped F2 fish in spring 2007
500 F3 progeny sampled in autumn 2007
Parentage analysis assigned each F3 progeny to an F2 mother
Lateral plate morph mapped to Eda
Fitness also mapped to Eda region
Two-fold fitness difference between genotypes
Change in frequency over a generation
Fitness increased with body size
Answers to specific questions
Comparison with a second introduced population over multiple generations
Loberg Lake Eda allele frequency over time
Do large-effect loci contribute to adaptation?
Taught by
EvoEcoSeminars
