BIO LECTURE 3 FRIDAY (Chapter 21)Phenotypic Plasticity: Which of these best represents qualitative variation? Which letter represents the mean of this distribution?
Considerable Genetic Variation in Populations Artificial selection represents an extreme case of showing you the breath of genetic variation that exists within a population that doesn’t look very different• Two examples of artificial selection (dogs and Brassica) are proof of this So....• How do we assess this genetic variation?• How can we use this variation to understand evolution? Assessing Genetic Variation• Can assess observable phenotypic variation (when phenotype = genotype) • e.g. Mendel’s pea experiments • snapdragons -We have to use molecular methods (molecular genetic analysis) when observable phenotypic variation is not available• Can measure genetic variation directly• many cheap and high-throughput methods• many based on the Polymerase Chain Reaction (PCR) Gel Electrophoresis -Used in the 70’s and 80’s to explain popular genetics. You mush a fly into a slab of jello, and you hit that with an electric current and what happens is that all the molecules start to move. The electricity moves it, the larger ones take longer. -This protein electrophoresis is based on the notion that we have variation in our proteins and those variations in proteins even just the difference in our amino acids can affect how those amino acids move through the gel. Shorter move faster, longer ones move slower.