Punnett SquareDirectional SelectionDisruptive SelectionStabilizing SelectionBIOM 182Bang, Michel(Christopher)2013 FallWeek 8Midterm # 2 Study GuideFebruary 28Study Guide*Know*- Punnett Square - Phenotype and Genotype Formulas  p+q=1 and p^2 +2pq+ q^2=1- Know the difference F1 and F2 Generation- Know how to interpret pedigreesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.- Basic ProbabilityEx. Flipping a coin, there is a 50/50 chance of it being heads or tails. When rolling a die, the chance of being “4” is 1/6.- Understand how alleles interact in determining Phenotypes- Know Deviations from Mendel’s standard crossesGene Interactions- Genes with multiple phenotypes Ex Black wolf, brown wolf, gray wolf, white wolf. Dominance hierarchy C> c^ch> c^h> cIncomplete Dominance-Pleiotropism- Single allele can have multiple phenotypic effectsEpistasis-Phenotypic expression of one gene is influenced by another geneHeterosis- A cross between 2 different true-breeding homozygotes can result in offspring with stronger, larger phenotypes: “Hybrid vigor” or heterosisPenetrance- Proportion of individuals in a population with certain genotype that show the phenotypeExressivity- Degree to which genotype is expressed in an individualQuantitative trait lociEpigenetics- Study of heritable changes in gene expression or cellular phenotype, cause by mechanisms other than changes in the underlying DNA sequence- Know how to use simple genetic rules on populationAll the alleles at all the gene loci in all the individuals in a population is called a gene pool- Be able to calculate genotype and allele frequencies for populationsNumber of Individuals of a certain genotype = Frequency of that genotypeTotal number of individuals Number of the sam alleles for a gene = Frequencey of that alleleTotal number of alleles for that gene- Understand when Evolution occurs- Understand the history of evolutionEvolution- Is the genetic makeup of a population from generation to generation- Understand the basics of Natural Selection- Natural Selection is the force behind adaptation to local conditions- Observations-All species produce an excess of offspring. Populations stabilize in size- Inference 1- Environment cannot support all offspring that produced, many do not survive.- Observation-members population vary in their characteristics- Inference 2-Survivial and reproduction depend on inherited traits- Learn different types of selection Directional Selection Disruptive Selection Stabilizing Selection- Know what affects evolution and Genetic Variation1. Sexual Reproduction results in new combinations of genes through crossing over and independent assortment, and combination of gametes2. Frequency-Dependent Selection- A polymorphism can be maintained when fitness depends on its frequency in the population 3. Enviromental Variation- Helps to preserve genetic variation 4. Subpopulations- Different geographic regions maintain genetic variation5. Mutations- (changes in DNA) can result in new allele varieties