BIO 321 Lecture Notes - Lecture 24: Phenotypic Plasticity, Size Pair, Pleiotropy
Document Summary
How to detect genetic vs. environmental effects: common garden experiment. Place some replicates of strains in each of two or more environments, one of which is the native environment interpreting results: if evidence for genetically based differences. Genetic divergence (presumably at least somewhat adaptive) if little or no evidence for genetic basis for differences. Phenotypic plasticity (presumably at least somewhat adaptive) Calculating dn and ds: need to know the total number of nonsynonymous sites . Total number of nucleotide sites that can potentially change to encode a different amino acid for that codon dn=actual number of nonsynonymous differences per nonsynonymous site: need to know the total number of synonymous sites . Total number of nucleotide sites that can potentially change to encode the same amino acid ds=actual number of synonymous differences per synonymous site. An example from a very short coding sequence (9 nt, 3 aa) For act/thr, the third position is 4-fold degenerate => act=aca=acc=acg=thr.
