Concordance for heightbetween Age monozygotic twin pairs dizygotic twin pairs of the same sex Birth 3 months 6 months 12 months 24 months 3 years 5 years 8 years 0.62 0.78 0.80 0.86 0.89 0.93 0.94 0.94 0.79 0.72 0.67 0.66 0.54 0.56 0.51 0.49 (a) If heightwere entirely genetically controlled, what concordance would you expect between monozygotic twin pairs? Explain your answer. Does data for eight-year-old twins suggest that heightis largely controlled by genetic factors? Explain you answer. (b) (c) Suggest an explanation for the low concordance at birth for monozygotic twins.

28

1₁ F3 8 A = all of the dominant alleles for a particular trait in a specific population; a = all of the recessive alleles for a particular trait in a specific population In the following equations "A" is represented by "p" "a" is represented by "q" Hardy Weinberg equations: Allele distributions in Generation 1: 36 homozygous dominant individuals 13 heterozygous individuals 1 homozygous recessive individual Explanation of terminology: px p=p² There are 50 individuals in this particular population. We want to see if allele distributions change from generation to generation. We will use the Hardy Weinberg equations to find out. Due to migration and random mating of the parent generation, the percentage of homozygous recessive genotypes in Generation 2 offspring increases, changing_"a" to 40%, so a = 40 If "a" = .40, and "a"=q, then q = $ Remember that p + q = 1.0 If q, then p must = How many of these 50 offspring are homozygous dominant, heterozygous, or homozygous recessive? p² + 2pq+q²=…

Student Name: Alyssa york The Hardy-Weinberg Equation 4. Cystic fibrosis is a homozygous recessive condition that affects 1 in 10,000 of the Hispanic population in the United States. Calculate the frequency of the dominant allele, the frequency of the recessive allele, and the percentage of heterozygous individuals (carriers) in the Hispanic population. P qFrequency of the recessive allele 2 p² q² Frequency of the dominant allele 2pq % homozygous dominant % homozygous recessive % heterozygous 0.98 0.02 96.04.7. 0.0.4%