Define lethal genes, epistasis, linked genes, and polygenic inheritance. Also, calculate allele frequencies for a trait controlled by dominant/recessive alleles where 4% express the recessive phenotyp

Here are the answers to question 7: 7.a. Define the following terms: i. Lethal genes: These are genes whose expression results in the death of the organism, often at an early stage of development, before or shortly after birth. ii. Epistasis: This is a phenomenon where the expression of one gene (the epistatic gene) masks or modifies the effect of another gene (the hypostatic gene) at a different locus. iii. Linked genes: These are genes that are located on the same chromosome and are therefore inherited together more often than genes on different chromosomes. iv. Polygenic inheritance: This is a type of inheritance where a single phenotypic trait is determined by the cumulative effect of two or more genes, often resulting in a continuous range of phenotypes. 7.b. A certain autosomal trait is controlled by a dominant allele A and a recessive allele a. In a large randomly mating population, 4% of individuals express the recessive phenotype. i. Calculate the frequency of the recessive allele (a) and the dominant allele (A). The frequency of individuals expressing the recessive phenotype is given as 4%, which corresponds to the frequency of the homozygous recessive genotype (aa). Let q be the frequency of the recessive allele (a) and p be the frequency of the dominant allele (A). According to the Hardy-Weinberg principle: q^2 = frequency of homozygous recessive genotype (aa) q^2 = 0.04 To find the frequency of the recessive allele q: q = sqrt(0.04) q = 0.2 The sum of allele frequencies is p + q = 1. To find the frequency of the dominant allele p: p = 1 - q p = 1 - 0.2 p = 0.8 The frequency of the recessive allele (a) is 0.2. The frequency of the dominant allele (A) is 0.8. ii. Calculate the expected frequencies of the three genotypes in the population. The three genotypes are AA, Aa, and aa. Their frequencies are given by the Hardy-Weinberg equation: p^2 + 2pq + q^2 = 1. Frequency of homozygous dominant genotype (AA): p^2 = (0.8)^2 p^2 = 0.64 Frequency of heterozygous genotype (Aa): 2pq = 2 × 0.8 × 0.2 2pq = 0.32 Frequency of homozygous recessive genotype (aa): q^2 = (0.2)^2 q^2 = 0.04 The expected frequency of genotype AA is 0.64. The expected frequency of genotype Aa is 0.32. The expected frequency of genotype aa is 0.04. iii. State four conditions necessary for this population to remain in Hardy-Weinberg equilibrium. 1. No mutation: There should be no new alleles introduced or existing alleles changed. 2. No gene flow: There should be no migration of individuals into or out of the population. 3. Random mating: Individuals must mate randomly, without any preference for specific genotypes. 4. No natural selection: All genotypes must have equal survival and reproductive rates. 5. Large population size: The population must be large enough to avoid random fluctuations in allele frequencies (genetic drift). What's next?