Review of Mendelian Genetics and Population Genetics Prep for lab tomorrow: Chapter 5

Autosomal inheritance Hand-clasping

X-linked inheritance Red-green color blindness

Population genetics Is evolution taking place in a population? Evidence: – 1. Statistical analysis of phenotypic attributes – 2. Change in allele frequencies.

Human controlled crosses One gene; two alleles Probability of getting particular genotypes Based on frequencies of alleles Same cross can be depicted as (G + g) x (G + g) = (G + g) 2 = G 2 + 2Gg + g 2 Generalized case: (p + q) 2 = p 2 + 2pq + q 2 Hardy-Weinberg equilibrium formula Allele frequencies  0.5 G; 0.5 g Genotype frequencies  Phenotype frequencies  So evolution can be defined as a change in allele frequencies.

In natural populations Alleles segregate into different gametes in the same way, but Individuals free to choose mates If individuals chose mates randomly, then genotypic and phenotypic frequencies depend on allele frequencies.

Information from individuals in Lab Section 2, with no individuals added from Regis population.. Hand clasping: 15 dominant (L on R) : 3 recessive (R on L) N = 18 15/18 individuals are either C/C or C/c0.83 3/18 individuals ARE c/c0.17 Is the population sampled in genetic equilibrium? Need to know the frequencies of C and c. Then plug the frequencies into the Hardy-Weinberg formula Represents one generation of random mating q 2 = frequency of c/c = 0.17 q = square root of q 2 = square root of 0.17 = P + q = 1 p = 1 – q = 1 – = p 2 + 2pq + q 2 = 1 (0.5877) 2 + 2(0.5877)(0.4123) + (0.4123) = 1 P = ½(0.4846) = q = ½ (0.4846) = Have frequencies of C and c changed after one generation of random mating. Observed p and q Expected p and q