Concept explainers
In humans, the ability to bend the thumb back beyond vertical is called hitchhiker's thumb and is dominant to the inability to do so (OMIM 274200; see Problem 41). Also, the presence of attached earlobes is recessive to unattached earlobes (OMIM 128900).
a. Check your own
b. Using all available and willing members of your family, or members of another family if yours is not easily accessible, trace the transmission of both traits in a pedigree. Use allelic symbols H and h for the thumb and E and e for earlobes, and identify the genotypes for each family member as completely as possible. Bring the pedigree back to share with your group.
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Study Guide And Solutions Manual For Genetic Analysis: An Integrated Approach
- Draw a punnett square for each problem. Please be careful to notice whether a trait is homozygous or heterozygous. In rabbits it has been shown that albino (white) is recessive to the brown color, such as in the wild rabbit. If a homozygous albino rabbit and a homozygous brown rabbit are bred, what will be the color ratio of the first generation? Answer:___________brown _____________tan______________white 2. If a pure (homozygous) white guinea pig is bred with a hybrid (heterozygous) black guinea pig, what would be the probable color ratio of the next generation? Black is dominant. White is recessive. Answer:___________black _____________gray _____________white Thank you.arrow_forwardIn humans, brown eyes are dominant to blue eyes, and the ability to roll your tongue is dominant to not being able to roll your tongue. If a mother who was heterozygous for eye colour and homozygous recessive for tongue rolling had a baby with a father that was heterozygous for both traits, what is the probability that their child would have blue eyes and could roll their tongue?arrow_forwardA couple who are about to get married learn from studying their family histories that, in both their families, theirunaffected grandparents had siblings with cystic fibrosis(a rare autosomal recessive disease).a. If the couple marries and has a child, what is theprobability that the child will have cystic fibrosis?b. If they have four children, what is the chance that thechildren will have the precise Mendelian ratio of 3:1 fornormal:cystic fibrosis?c. If their first child has cystic fibrosis, what is theprobability that their next three children will be normal?arrow_forward
- A couple seeks advice from a genetic counselor because they know that they are both carriers for cystic fibrosis (which is autosomal recessive), and the woman is a carrier for Duchenne muscular dystrophy (which is sex-linked recessive). For each of their future sons and daughters (calculate separately), what is the probability that they will be affected for: Cystic fibrosis Duchenne muscular dystrophyarrow_forwardIf an AaBbCcdd male mates with an AaBbCCDd female: A) What is the minimum number of ridge-producing genes possible in one of their children? B) What would the be the TRC for this child if it is a male? C) If this child is a male, will he have a higher or lower TRC than the parent with the lower ridge count? D) What is the maximum number of ridge-producing genes possible in a child of this couple? E) If this child is a female, will she have a higher or lower TRC than the parent with the higher ridge count?arrow_forwardAside from the Punnett square, are there other ways to understand the inheritance of traits in humans, animals and/or plants? Give at least one and describe if there is.arrow_forward
- Above is a pedigree for colorblindness. Based on the pedigree, is the disease dominant or recessive and is it sex-linked or autosomal? Why? Furthermore, what is the probability that 18 on this chart is affected but the condition, and what is the probability that 18 is a carrier? Why? Are the probability of being a carrier and an affected individual different? Whyarrow_forwardColor blindness is typically an inherited genetic condition in which individuals have a decreased ability to see color or differences in color. Color blindness only occurs in individuals who have two recessive alleles for the condition. Normal color vision is due to a dominant allele (C) Color blindness is due to the recessive allele (c) a) If Susan is homozygous for normal vision, and Matt is homozygous for color blindness, what is the likelihood (in percentage) that their son Alex will have color blindness? Perform a Punnett Square (either below or by hand on paper) to find the probability. Provide your answer in a full sentence. If you did the Punnett Square by hand, attach your photo to the next question.arrow_forwardIn humans, the genetic disease cystic fibrosis is caused by a recessive allele (a). The normal (healthy) allele is dominant (A). What is the genotype of someone who has cystic fibrosis? What are the two different genotypes that a healthy person could have? If two people were both heterozygous for the cystic fibrosis gene, what fraction of their children would be likely to have this disease? Hint: Draw a Punnett square to figure it out.arrow_forward
- The condition phenylketonuria is caused by a recessive allele. There are two carriers who have progeny.a. Give the gene notation. b. Give the expected genotypic and phenotypic ratios. c. What is the probability that their child will be heterozygous if they have a normal child?d. What is the probability of having two affected children and one normal child if they have three children?arrow_forwardDuchenne muscular dystrophy is sex linked and usually affects only males. Victims of the disease become progressively weaker, starting early in life.a. What is the probability that a woman whose brother has Duchenne’s disease will have an affected child?b. If your mother’s brother (your uncle) had Duchenne’s disease, what is the probability that you have received the allele?c. If your father’s brother had the disease, what is the probability that you have received the allele?arrow_forwardIn cats, a sex-linked recessive allele, d, results in dystrophin-deficient muscular dystrophy. Its dominant counterpart, D, results in normal levels of dystrophin in muscle. Also, the dominant allele F at an autosomal locus is responsible for polydactyly (the presence of extra digits on each foot) and the expression of its recessive counterpart f results in the absence of polydactyly (having the 5 digits per front paw, and 4 digits per hind paw). A healthy female cat that has polydactyly gives birth to a male kitten with the normal number or toes. In addition, this male kitten has muscular dystrophy. What can you conclude about the genotype of: Unknown alleles should be indicated with a “?" The son? The father? The mother?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