PHENOTYPE AND GENOTYPEDefinitions: phenotypeis the constellation of observable traits; genotypeis the genetic endowment of the individual. Phenotype = genotype + development (in a given environment). To consider these in the context of evolutionary biology, we want to know how these two are related. In a narrow "genetic" sense, the genotype defines the phenotype. But how, in and evolutionary sense, does the phenotype "determine" the genotype? Selection acts on phenotypesbecause differential reproduction and survivorship depend on phenotype. If the phenotype affecting reproduction or survivorship is genetically based, then selection can winnow out genotypes indirectly by winnowing out phenotypes. How do we get from genotype to phenotype? Central dogma: DNAvia transcription to RNAvia translation to protein; proteins can act to alter the patterns and timing of gene expressionwhich can lead to cytodifferentiationwhere cells take on different states; cell communication can lead to pattern formationand
This is the end of the preview.
access the rest of the document.