GENETICS AND GENETIC VARIATION 03 23 2015 Description of an individual Locus location on a chromosome Gene unit on a chromosome Allele Genotype set of genes belonging to an individual Phenotype external characteristics of an individual Product of genes AND the environment Discrete Traits Gregor Mendel 1865 A trait in older generations can show up later several generations later even if it s not present in the generations between Mendelian Inheritance transmission of alleles from individual parents to Population Genetics transmission of alleles in a population from one individual offspring generation to the next Hardy Weinburg Equilibrium if an infinitely large random mating population is free from outside evolutionary forces then gene frequencies will not change over time and genotype frequencies in each generation will be f AA p 2 Where p f A and q f a Hardy Weinburg proportions f Aa 2pq f aa q 2 Heterozygosity basically an average of heterozygotes in a population Continuous Traits Normal Distribution bell curve Has an average x V x xi N Variance Standard Deviation S V 2 Coefficient of Variation CV S x Correlation rXY x xi y yi N SX SY Evolution requires genetic variation Not all variation is important for evolution Genetic Variation Additive Variation Nonadditive Genetic Variation VG VA VD Heritability Broad Sense Heritability Narrow Sense Heritability Relationship between parents to their offspring Ex Average height of parents predict offspring s average height Fate of Genetic Variation genetic variation can be lost due to selection Genetic variation is generated by Mutation Recombination 03 23 2015 03 23 2015