Consider a rare deleterious recessive allele for a specific gene/locus. In this hypothetical population, the deleterious recessive allele exists at a proportion of 0.01. In an offspring with randomly chosen parents, what is the probability that the offspring will be homozygous for the deleterious recessive allele [q]?

An autosomal locus has alleles A and a. We are given the frequency of individuals with the autosomal recessive phenotype. Which of the following statements is TRUE?  Choose all that are true. Note: HWE = Hardy-Weinberg equilibrium a) If we assume HWE, we can calculate both allele frequencies b) If we assume HWE, we can calculate the genotype frequencies that we weren't given c) We can calculate both allele frequencies even if we don't assume HWE d) We can calculate q = Freq(a) even if we don't assume HWE e) Even if we don't assume HWE, we can calculate the genotype frequencies that we weren't given

You are studying a disorder that is based on the genetic cómposition at three loci. Assume that a dominant allele at any locus adds 7 units of risk for the disorder and that a recessive allele at any locus adds 4 units of risk for the disorder. Individuals with 26 or more units of risk develop the disorder. The environment does not affect the presence or absence of this disorder. How many risk units will be present in an individual of genotype AABbcc?

A mutation in an of the recessive hemoglobin gene on chromosome 11 causes sickle-cell disease, but also confers malaria resistance. The allele frequency in African Americans is 14%.  1. What percent of the population have two copies of the gene and are therefore immune to malaria? 2. What percent of the population are less susceptible to malaria but do not have sickle-cell anemia since they are heterozygous?

One particularly useful feature of the Hardy-Weinberg equation is that it allows us to estimate the frequency of heterozygotes for recessive genetic diseases, assuming that Hardy-Weinberg equilibrium exists. As an example, let’s consider cystic fibrosis, which is a human genetic disease involving a gene that encodes a chloride transporter. Persons with this disorder have an irregularity in salt and water balance. One of the symptoms is thick mucus in the lungs that can contribute to repeated lung infections. In populations of Northern European descent, the frequency of affected individuals is approximately 1 in 2500. Because this is a recessive disorder, affected individuals are homozygotes. Assuming that the population is in Hardy-Weinberg equilibrium, what is the frequency of individuals who are heterozygous carriers?

Sickle cell anemia is caused by a recessive allele at a single gene. As we discussed in class, being a homozygote for the sickle cell allele is almost always lethal, but heterozygotes tend to be resistant against malaria although they have a mild form of anemia. Because of this heterozygote advantage, the allele for sickle cell anemia has a frequency of more than 10% in some human populations.     How would present allele frequencies of the sickle cell allele change, if there was no heterozygote advantage or disadvantage (that is, that heterozygotes would be identical to ‘normal’ homozygotes – no malaria resistance, no anemia)? How would the change in sickle cell allele frequencies compare to scenario a (extirpation of malaria)

Tay-Sachs disease is a recessive genetic disease. Individuals with this disease rarely survive past the age of four. In the general population, approximately 1 person in 300 carries the allele for this disease. However, in some populations, including the Irish Americans, the Ashkenazi Jews, and the Cajuns from Louisiana, the proportion of Tay-Sachs carriers is much higher (1 in 27 to 1 in 50) than in other populations. Such high frequency of an otherwise rare allele is expected when    Question 24 options:   populations experienced disruptive selection   populations were founded by a small number of settlers   the allele is advantageous at the heterozygous state    populations have higher than average mutation rates   populations experienced stabilizing selection

There may be a number of possible alleles for a given gene within a population. In a multiple allele system the dominance relationships between the various alleles must be considered. One of the more familiar examples of a multiple allelic system is that of the human ABO blood group. The gene involved codes for a protein located on the outside of red blood cell membranes. Three alleles (IA, IB and i) determine whether the protein is present or absent and which form of the protein (if any) is present. The A and B alleles code for the A and B forms of the protein and are co-dominant with each other. The O allele (i) codes for no protein and is recessive to both A and B alleles. This means there are four possible phenotypes (blood types: A, B, AB, and O). This also means there are 6 possible genotypes: IAIA, IBIB, IAi, IBi, IAIB and ii.  If you have the letter ‘O’ anywhere in any of your genotypes, you are doing it wrong. 6- A couple with the following blood types: the man has type AB and…

In a population of plants, leaf hairiness is determined by a single locus with two alleles: H and h. Out of 319 individuals in the population, 25 % are completely hairy, 9 % are partially hairy, and the remaining are hairless. Complete hairiness is caused by homozygosity of the H allele at a single locus; hairlessness is caused by homozygosity of the h allele at that locus; heterozygotes are partially hairy. What is the expected (predicted under H–W) number of individuals with partially hairy leaves?

In a hypothetical population, 16% have sickle-cell anemia.  The population is in Hardy-Weinberg equilibrium.  ( sickle-cell anemia is recessive) What is the frequency of the allele for sickle-cell anemia? What is the frequency of the allele for normal hemoglobin?