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Achromatopsia is a rare autosomal recessive form of complete color blindness that affects about
Achromatopsia was first recorded on Pingelap in the
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Genetic Analysis: An Integrated Approach (3rd Edition)
- Color blindness is a recessive sex linked disorder among humans. A colorblind man has a child with a woman who is a carrier of the disorder. Given the following genotypes: XN= normal vision and Xn = colorblindness, what is the chance of having colorblind daughters? * 100% 50% 25% 75%arrow_forwardIn Sweden 1/500 are born with an autosomal recessive disorder called thalassemia. What is the carrier frequency within the population?arrow_forwardIf the frequency of those exhibiting a monogenic autosomal recessive phenotype caused by a rare clinically relevant allele is 1/8500 in a given population, what is the carrier frequency? Please give your answer as a percentage to 3 decimal places, do not include the % symbol. ANSWER: In a population where the frequency of those exhibiting a monogenic autosomal recessive phenotype caused by only one known mutation is 1/8500 the carrier frequency is a percent.arrow_forward
- Click on the link: https://www.dailymail.co.uk/news/article-4168946/Mum-world-s-black-woman-two-white-babies.html#ixzz4hvs1FUeM.Links to an external site. This case explores how skin color is inherited in humans, presented in the story of Catherine and Richard Howarth whose children are surprisingly light skinned compared to their Nigerian mother. Based on what you have learned about polygenic inheritance, explain how Richard and Catherine Howarth were able to produce light-skinned babies. Are the odds indeed 1 in a million? Include possible genotypes of the couple and their children to support your argument.arrow_forwardIdentify each of the following as an example of allele, genotype, and/or phenotype frequency: A. Approximately 1 in 2500 people of Northern European descent is born with cystic fibrosis. B. The percentage of carriers of the sickle cell allele in West Africa is approximately 13%. C. The number of new mutations for achondroplasia, a genetic disorder, is approximately 5 × 10–5.arrow_forwardSickle 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)arrow_forward
- A form of learning disabilities and speech impairment results from a recessive mutation in the HERC2 gene. The next 4 questions are about this mutation. In a small Amish village in Ohio, about 5 per 1000 births are affected with this disorder. Assume Hardy Weinberg equilibrium. What is the frequency of the dominant WT HERC2 allele in this small village? A form of learning disabilities and speech impairment results from a recessive mutation in the HERC2 gene. The next 4 questions are about this mutation. Part a: In a small Amish village in Ohio, about 5 per 1000 births are affected with this disorder. Assume Hardy Weinberg equilibrium. What is the frequency of the dominant WT HERC2 allele in this small village? a)0.005 b)0.995 c)0.07 d)0.93 Part b: What is the estimated total number of homozygous dominant individuals in this village of 1000 people? a) 70 b) 930 c) 860 d) 140arrow_forwardTay-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. Which evolutionary scenario can be predicted to produce a high frequency of Tay-Sachs disease in these populations? Select one: a. All three populations descend from a small number of settlers b. The Tay-Sachs allele is advantageous at the heterozygous state c. These populations experienced disruptive selection d. These populations experienced stabilizing selection e. These populations have higher than average mutation ratesarrow_forwardHumans who are born homozygous for the recessive sickle cell allele die of sickle cell anemia, while those who are heterozygous are resistant to malaria. 5% of the population of the Congo are homozygous recessive for the sickle cell allele. What percentage of the population is resistant to malaria?arrow_forward
- Hereditary hemochromatosis is an autosomal recessive genetic disorder that causes the body to absorb too much iron from the diet. This excess iron is stored in the body's tissues and organs, particularly the skin, heart, liver, pancreas, and joints. Because humans cannot increase the excretion of iron, excess iron can overload and eventually damage tissues and organs. Some individuals who are homozygous for this autosomal recessive gene experience only skin discoloration and joint pain, others experience heart disease in addition to the skin discoloration, still other individuals suffer also suffer from diabetes, severe heart disease, and liver damage. Name and define this genetic phenomenon and explain how it relates to this specific genetic situation described above.arrow_forwardIn the genetics unit you learned that sickle cell anemia is an autosomal recessive condition. In 2016, assume in the City of Markham there are 1000 people out of 300000 people who have sickle cell anemia. Assume global warming continues for the next 50 years and in the year 2066 there are 20000 people out of 500000 in Markham who have sickle cell anemia. a)What are the allele frequencies in 2016? What are the allele frequencies in 2066? Is microevolution evident? b)Due to global warming, assume the numbers of malaria carrying mosquitoes in Markham dramatically increased between 2016 and 2066. What do you believe is the main cause of the microevolution in Markham? (Hint- refer to the 5 factors affecting microevolution and refer back…arrow_forwardAn individual with a form of red-green color blindness processes a genetically inherited trait that makes it difficult to distinguish red and green color hues. Red-green color blindness tends to skin generations and it is found much more often in men than in women. If a man who was normal and a woman who is a carrier for this form of colorblindness have a child, when the probability that the child will be red-green colorbind is: -0% -25% -50% -75% -100%arrow_forward
- Human Biology (MindTap Course List)BiologyISBN:9781305112100Author:Cecie Starr, Beverly McMillanPublisher:Cengage LearningHuman Heredity: Principles and Issues (MindTap Co...BiologyISBN:9781305251052Author:Michael CummingsPublisher:Cengage Learning