Can you please explain the question on the bottom left? I am confused on why the
ID: 177049 • Letter: C
Question
Can you please explain the question on the bottom left? I am confused on why they are multiplying 1/64 by 4. Please explain this in great detail. :)
recognition systems that prevent fertilization between indi 1/64. To calculate an overa Value viduals with the same alleles atkey loci However, the form of of F for the pink female as a child ofa first-cousin marriage nonrandom mating most commonly found to affect genotype remember that she could also inherit two copies of any of frequencies in population genetics is inbreeding. the other three alleles present in her great-grandparents. Because any of four possibilities would give the pink female Inbreeding two alleles identical by descent from an ancestral cop Inbreeding occurs when mating individuals are more closely 4 x (1/64) 1/16 related than any two individuals drawn from the population at random loosely defined, inbreeding is mating among rela tives. For a given allele, inbreeding increases the proportion of NOW SOLVE THIS homozygotes in the population. A completely inbred popula- tion will theoretically consist only ofhomozygous genotypes 25-4 Aprospective groom, who is normal, has a sister with cystic fibrosis (CF), an autosomal recessive disease. To describe the intensity of inbreeding in a population, Their parents are nommal. The brother plans to marry a geneticist Sewall Wright devised the coefficient of inbreed woman who has no history of CF in her family. What is ng (F). F quantifies the probability that the two alleles of the probability that they will produce a CF child? They a given gene in an individual are identical because they are are both Caucasian, and the overall frequency of CF in descended from the same single copy ofthe allele in an ances the Caucasian population is 1/2500-that is, 1 affected tor. If F 1, a ll individuals in the population are homozy- child per 2500. (Assume the population meets the Hardy- gous, and both alleles in every individual are derived from Weinberg assumptions the same ancestral copy. If F 0, no individual has two T: This problem involves an understanding of how recessive HIN alleles derived from a common ancestral copy alleles are transmitted (see Chapter 3) and the probability of he method of estimating F for an individual is sho receiving a recessive allele from a heterozygous parent. The key n Figure 25-16. The fourth-generation female (shaded to its solution is to first work out the probability that each parent pink) is the daughter of first cousins (yellow). Suppose her carries the mutantallele, great-grandmother (green) was a carrier of a recessive letha allele, a. What is the probability that the fourth-generation female w herit two copies of her great-grandmother's ethal allele? For this to happen, (1) e great-grandmother had to pass a copy of the allele to her son, 2) her son had to 25.9 Reduced Gene Flow, Selection pass it to his daughter, and (3) his daughter had to pass it to and Genetic Drift Can Lead to her daughter (the pink female). Also, (4) the great-grand Speciation mother had to pass a copy of the allele to her daughter, (5 her daughter had to pass it to her son, and (6) her son had A species can be defined as a group ofactually or pote ally o pass it to his daughter (the pink female). Each of the six interbreeding organisms t is reproductively isolated in necessary events has an individual probability of 1/2, and they all have to happen, so the probability that the pink nature from all other such groups. In sexually reproducing female will inherit two copies of her great-grandmother's organisms, speciation transforms the parental species into another species, or divides a single species into two or more separate species. Changes in mor- phology or physiology and adapta tion to ecological niches may also occur but are not necessary compo nents of the speciation event Populations within a species may carry considerable genetic The chance that this female wi nherit two variation, present as differences copies of her great-grandmothe r's a allele is n alleles or allele frequencies at a variety of loci. Genetic divergence Because the female's two alleles could be identical of these populations can reflect the by descent from any of four different alleles, action of natural selection, genetic F 4 X drift, or both. In an earlier section we saw that the migration of indi FIGURE 25-16 Calculating the coefficient ofinbreeding (F) for the offspring of a viduals between populations tends first cousin marriage.Explanation / Answer
1/64 is the possibility that the recessive allele is inherited to the female.
They are multiplying by 4 because the ancestors (blue) married from outside there will be two more different alleles added to this already existing 2 alleles . Take it as C and D . So she will receive 2 copies of any of the 4 alleles, (A,a,C,D). Sothey are multiplying by 4.