Consider two linked autosomal genes. The dominant allele C of the first gene causes cataracts of the eye, whereas its recessive allele produces normal eyes. The dominant allele P causes polydactyly (an extra finger) whereas its allele (p) produces a normal number of fingers. A man with cataracts and normal fingers marries a woman with polydactyly and normal eyes. Their son has both polydactyly and cataracts and he marries a woman with neither trait. What is the probability that their first child will have cataracts and polydactyly?

People who can roll their tongues contain a dominant allele for tongue rolling. If people do not contain the tongue rolling gene, then they cannot roll their tongue no matter how hard they try. Consider the following situation: If a homozygous dominant tongue roller mates with a homozygous recessive non-tongue roller, then what is the probability of the offspring inheriting the tongue rolling gene?

Question 87 - According to Hardy-Weinberg Equation, p x p + 2 x p x q + q x q = 1 where p = dominant allele frequency and q = recessive allele frequency. Let p + q = 1. Fraction of population has 2 copies of the p gene = p x p. Fraction of population has 2 copies of the q gene = q x q. Fraction of population has a copy of p gene and a copy of q gene = 2 x p x q. In a small town, the allele frequency is q = 0.2 for a recessive gene, the delta-32 mutation, that gives human protection from HIV infection. (a) Find the allele frequency a dominant gene, p. (b) What percent of the population has at least a copy of the gene that cause the population either immune to HIV or less susceptible to the disease?

GENETIC ENGINEERING - EXAMPLE 27.4 : According to Hardy-Weinberg Equation, p x p + 2 x p x q + q x q = 1 where p = dominant allele frequency and q = recessive allele frequency. Let p + q = 1. Fraction of population has 2 copies of the p gene = p x p. Fraction of population has 2 copies of the q gene = q x q. Fraction of population has a copy of p gene and a copy of q gene = 2 x p x q. In a small town, the allele frequency is q = 0.2 for a recessive gene, the delta-32 mutation, that gives human protection from HIV infection. (a) Find the allele frequency of a dominant gene, p. (b) What percent of the population has at least a copy of the gene that cause the population either immune to HIV or less susceptible to the disease?