Genetics: From Genes to Genomes
6th Edition
ISBN: 9781259700903
Author: Leland Hartwell Dr., Michael L. Goldberg Professor Dr., Janice Fischer, Leroy Hood Dr.
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 21, Problem 17P
Androgenetic alopecia (pattern baldness) is a complex trait in humans governed by several genes, but suppose a human population exists in which a single autosomal allele determines pattern baldness. This allele is dominant in males and recessive in females. The population is in Hardy-Weinberg equilibrium, and 51% of the men are bald.
| a. | What is the allele frequency of the baldness allele among males? |
| b. | What is the allele frequency of the baldness allele among females? |
| c. | What percentage of the women in this population will exhibit pattern baldness? |
| d. | Assuming random mating, what proportion of all matings should be between a bald man and a Page 742 nonbald woman? |
| e. | What percentage of the bald men in the population are heterozygotes? |
| f. | If a nonbald couple produces a bald son, what is the probability that their next son will be bald? |
| g. | A woman with androgenetic alopecia has a daughter, but nothing is known about the father. What is the probability that the daughter will be bald? |
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
Excessive secretion of male sex hormones results in premature sexual maturation in
males and masculization of the sex characters in females. This disorder is called the
adrenogenital syndrome, and in Switzerland there is an autosomal recessive form of
the disease that affects about one in 5000 newborns.
a. Assuming random mating, what is the allele frequency of the recessive?
b. What is the frequency of heterozygous carriers?
Albinos produce very little of the pigment melanin in their skin and hair. Albinism is inherited as a homozygous recessive trait. In North America, about 1 in 20,000 people are albinos.
a. What is the frequency of the dominant allele for albinism?b. What is the frequency of albinos?c. What is the frequency of heterozygotes?
Cystic fibrosis (CF) is a recessive autosomal disorder. In certain populations of Northern European descent, the number of people born with this disorder is about 1 in 2500. Assuming Hardy- Weinberg equilibrium for this trait:
A. What are the frequencies for the normal and CF alleles?
B. What are the genotype frequencies of homozygous normal, heterozygous, and homozygous affected individuals?
C. Assuming random mating, what is the probability that two phenotypically unaffected heterozygous carriers will choose each other as mates?
Chapter 21 Solutions
Genetics: From Genes to Genomes
Ch. 21 - Choose the best matching phrase in the right...Ch. 21 - When an allele is dominant, why does it not always...Ch. 21 - A population with an allele frequency p of 0.5 and...Ch. 21 - In a certain population of frogs, 120 are green,...Ch. 21 - Which of the following populations are at...Ch. 21 - A dominant mutation in Drosophila called Delta...Ch. 21 - A large, random mating population is started with...Ch. 21 - Prob. 8PCh. 21 - Alkaptonuria is a recessive autosomal genetic...Ch. 21 - Two hypothetical lizard populations found on...
Ch. 21 - It is the year 1998, and the men and women sailors...Ch. 21 - a. Alleles of genes on the X chromosome can also...Ch. 21 - In 1927, the ophthalmologist George Waaler tested...Ch. 21 - The equation p2 2pq q2> = 1 representing the...Ch. 21 - A gene has two alleles A frequency = p and a...Ch. 21 - Some people can taste the bitter compound...Ch. 21 - Androgenetic alopecia pattern baldness is a...Ch. 21 - The following figure shows the FBI-style analysis...Ch. 21 - Why is the elimination of a fully recessive...Ch. 21 - Tristan da Cunha is a group of small islands in...Ch. 21 - Small population size causes genetic drift because...Ch. 21 - Three basic predictions underlie genetic drift in...Ch. 21 - A mouse mutation with incomplete dominance t =...Ch. 21 - In Drosophila, the vestigial wings recessive...Ch. 21 - In a population of infinite size, three loci A, B,...Ch. 21 - You have identified an autosomal gene that...Ch. 21 - In Europe, the frequency of the CF allele causing...Ch. 21 - An allele of the G6PD gene acts in a recessive...Ch. 21 - Explain why evolutionary biologists monitor...Ch. 21 - Tiny foxes live on the Channel Islands off the...Ch. 21 - What is the most straightforward evidence at the...Ch. 21 - In March 2013, the American Journal of Human...Ch. 21 - If you go back 40 generations into your biological...Ch. 21 - In Fig. 21.17, to what part of the world does...Ch. 21 - Predict the DNA sequences at the four nodes...Ch. 21 - A cladogram not drawn to scale for the taxonomic...Ch. 21 - As noted in Fig. 21.22, humans now living in...Ch. 21 - As of this writing in 2016, no Neanderthal-derived...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, biology and related others by exploring similar questions and additional content below.Similar questions
- For each of the following characteristics, indicate whether it would be considered a discontinuous characteristic or a quantitative characteristic. Briefly justify your answer. a. Kernel color in a strain of wheat, in which two codominant alleles segregating at a single locus determine the color. Thus, there are three phenotypes present in this strain: white, light red, and medium red. b. Body weight in a family of Labrador retrievers. An autosomal recessive allele that causes dwarfism is present in this family. Two phenotypes are recognized: dwarf (less than 13 kg) and normal (greater than 23 kg). c. Presence or absence of leprosy. Susceptibility to leprosy is determined by multiple genes and numerous environmental factors. d. Number of toes in guinea pigs, which is influenced by genes at many loci. e. Number of fingers in humans. Extra (more than five) fingers are caused by the presence of an autosomal dominant allele.arrow_forwardCystic fibrosis (CF) is a recessive autosomal disorder. In certainpopulations of Northern European descent, the number of peopleborn with this disorder is about 1 in 2500. Assuming Hardy-Weinberg equilibrium for this trait:A. What are the frequencies for the common (non-disease-causing)allele and the mutant (disease-causing) allele.B. What are the genotype frequencies of homozygous unaffected,heterozygous, and homozygous affected individuals?C. Assuming random mating, what is the probability that twophenotypically unaffected heterozygous carriers will chooseeach other as mates?arrow_forwardAssume a large population has two alleles, B and b, for a particular trait that displays a normal pattern of Mendelian inheritance. If 49% of the population displays the recessive phenotype for this trait.. a. What percent of the population would be heterozygous (Bf)? b. What percent of the population would be homozygous dominant (BB)? c. What percent of the population would display the dominant phenotype? d. What is the frequency of the recessive allele (b) expressed as a percentage? e. What is the frequency of the dominant allele (B) expressed as a percentage? Place the number in the space provided without any other symbols. MEarrow_forward
- Color blindness in humans is an X-linked recessive trait. Approximately10% of the men in a particular population are color blind.a. If mating is random with respect to the color-blindness locus, what isthe frequency of the color-blindness allele in this population?b. What proportion of the women in this population are expected to becolor blind?c. What proportion of the women in this population are expected to beheterozygous carriers of the color-blindness allele?arrow_forwardCystic fibrosis is an autosomal recessive disease characterized by two copies of a mutated CFTR gene. If one in 100 (hypothetical scenario, not reality) people in the United States have cystic fibrosis, calculate the p and q frequency for the normal allele (p) and the mutated allele (q). Based on those calculations, what percentage of individuals would be expected to be homozygous dominant?arrow_forwardThe achoo syndrome (sneezing in response to bright light) and trembling chin (triggered by anxiety) are both dominant traits in humans. A. What is the probability that the first child of parents heterozygous for both the achoo gene and trembling chin will have achoo syndrome but lack trembling chin? B. If the same couple decides to have five children what is the probability that at most three will have achoo syndrome? C. If the same couple decides to have five children what is the probability that at most three will have achoo syndrome?arrow_forward
- In humans, there is a gene that influences the ability to smell the thioesters present in urine after asparagus is eaten. The ability to smell these compounds is an autosomal dominant trait. A is dominant and confers the ability to smell these thioesters a is recessive and does NOT confer the ability to smell these thioesters p = freq (A) = frequency of allele A in the population = number of A alleles/ total number of alleles %3D q = freq (a) = frequency of allele a in the population where p + q = 1 and, therefore, p? + 2pq + q? = 1 and %3D %D p? = freq (AA) = frequency of genotype AA = number of AA individuals/ total number of individuals %3D 2pq = freq (Aa) = frequency of genotype Aa q? = freq (aa) = frequency of genotype aa Phenotype Number of People Able to smell thioesters 378 Unable to smell thioesters 1323 Total 1701 1. Calculate p and q for this population. 2. Calculate p?, 2pq, and q? for this population.arrow_forwardSuppose there is an autosomal locus of 2 alleles, A1 and A2, with probabilities (frequencies) p1 and p2, and the genotype probabilities (frequencies) are P(A1A1) = p1*p1, P(A1A2) = 2*p1*p2, and P(A2A2) = p2*p2, respectively. Prove the Hardy-Weinberg Law, i.e., after one generation of random mating, the genotype probabilities (frequencies) in the offspring are also P(A1A1) = p1*p1, P(A1A2) = 2*p1*p2, and P(A2A2) = p2*p2. Hint: List all possible combinations of random mating. Then list the probabilities of the resulting genotype probabilities (frequencies) in the offspring. Combine the probabilities of random mating and resulting genotype probabilities (frequencies) in the offspring.arrow_forwardA pedigree analysis was performed on the family of a man with schizophrenia. Based on the known concordance statistics, would his MZ twin be at high risk for the disease? Would the twins risk decrease if he were raised in an environment different from that of his schizophrenic brother?arrow_forward
- In cats, the allele for black fur (B) is dominant over the allele for brown fur (b). A heterozygous female cat mated with a homozygous recessive male cat.a. What is the genotype of the female cat?b. What is the phenotype of the female cat?e. Draw a Punnett square to show what kinds of kittens these two cats could make. What fraction of the kittens would you expect to have each genotype?arrow_forwardFor the following five questions, A = true, and B = false 18. (2 pts) The dominance of an allele may vary for different traits. 19. (2 pts) Loss-of-function alleles are recessive, not dominant. 20. (2 pts) A haplosufficient allele is able to produce a wild-type phenotype in the heterozygous state. 21. (2 pts) The permissive temperature, which is usually lower than the normal growth temperature, is the temperature at which a mutant phenotype becomes observable. 22. (2 pts) In a cross between two true-breeding recessive mutants that are affected in different genes, the proportion of F1 progeny that show complementation (the wild-type phenotype) is affected by the map distance between the two genes.arrow_forwardAllele B is a deleterious autosomal dominant. The frequency of affected individuals is 4.0 × 10−6. The reproductive capacity of these individuals is about 30 percentthat of normal individuals. Estimate μ, the rate at whichb mutates to its deleterious allele B. Assume that the frequencies of the alleles are at their equilibrium values.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Human Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning
Human Heredity: Principles and Issues (MindTap Co...
Biology
ISBN:9781305251052
Author:Michael Cummings
Publisher:Cengage Learning
How to solve genetics probability problems; Author: Shomu's Biology;https://www.youtube.com/watch?v=R0yjfb1ooUs;License: Standard YouTube License, CC-BY
Beyond Mendelian Genetics: Complex Patterns of Inheritance; Author: Professor Dave Explains;https://www.youtube.com/watch?v=-EmvmBuK-B8;License: Standard YouTube License, CC-BY