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
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Textbook Question
Chapter 7, Problem 50P
Most mammals, including New World primates such as marmosets (a kind of monkey), are dichromats: They have only two kinds of rhodopsin-related color receptors. Old World primates such as humans and gorillas are trichromats with three kinds of color receptors. Primates diverged from other mammals roughly 65 million years ago (Myr), while Old World and New World primates diverged from each other roughly 35 Myr.
a. | Using this information, define on Fig. 7.32d the time spans of any events that can be dated. |
b. | Some New World monkeys have an autosomal color receptor gene and a single X-linked color receptor gene. The X-linked gene has three alleles, each of which specifies a photoreceptor that responds to light of a different wavelength (all three wavelengths are different from that recognized by the autosomal color receptor). How is color vision inherited in these monkeys? |
c. | About 95% of all light-receiving neurons in humans and other mammals are rod cells containing rhodopsin, a pigment that responds to low-level light of many wavelengths. The remaining 5% of light-receiving neurons are cone cells with pigments that respond to light of specific wavelengths of high intensity. What do these facts suggest about the lifestyle of the earliest mammals? |
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In a study of a muscle disorder, several affected families exhibited vision problems, muscle weakness, and deafness (M. Zeviani et al. 1990. American Journal of Human Genetics 47:904–914). Analysis of the mtDNA from affected members of these families revealed that large numbers of their mtDNA molecules possessed deletions of varying lengths. Different members of the same family and even different mitochondria from the same person possessed deletions of different sizes, so the underlying defect appeared to be a tendency for the mtDNA of affected persons to have deletions. A pedigree of one of the families studied is shown below. The researchers concluded that this disorder is inherited as an autosomal dominant trait, and they mapped the diseasecausing gene to a position on chromosome 10 in the nucleus.
Q. What characteristics of the pedigree rule out inheritance of a trait encoded by a gene in the mtDNA as the cause of this disorder?
In a study of a muscle disorder, several affected families exhibited vision problems, muscle weakness, and deafness (M. Zeviani et al. 1990. American Journal of Human Genetics 47:904–914). Analysis of the mtDNA from affected members of these families revealed that large numbers of their mtDNA molecules possessed deletions of varying lengths. Different members of the same family and even different mitochondria from the same person possessed deletions of different sizes, so the underlying defect appeared to be a tendency for the mtDNA of affected persons to have deletions. A pedigree of one of the families studied is shown below. The researchers concluded that this disorder is inherited as an autosomal dominant trait, and they mapped the diseasecausing gene to a position on chromosome 10 in the nucleus.
Q. Explain how a mutation in a nuclear gene might lead to deletions in mtDNA.
. Certain people are able to taste the chemical phenylthiocarbamide (PTC) when it is present in wet filter paper. These people are called 'tasters'. Others are unable to detect PTC and have the 'nontaster' phenotype. PTC tasting is an example of variation in sensory perception, and the genetic basis is thought to be rather simple. The ability to taste PTC is attributed to a dominant allele, denoted T, located on chromosome 7. The recessive allele is designated t. From analysis of pedigrees, 259 taster children and 278 non taster progeny were observed where one parent was heterozygous and could 'taste' PTC and the other parent was a 'nontaster'. Does this data set support the suggestion that his variation is due to a simple Mendelian pattern?
Chapter 7 Solutions
Genetics: From Genes to Genomes
Ch. 7 - The following is a list of mutational changes. For...Ch. 7 - What explanations can account for the following...Ch. 7 - The DNA sequence of one strand of a gene from...Ch. 7 - Among mammals, measurements of the rate of...Ch. 7 - Over a period of several years, a large hospital...Ch. 7 - Suppose you wanted to study genes controlling the...Ch. 7 - In a genetics lab, Kim and Maria infected a sample...Ch. 7 - The results of the fluctuation test Fig. 7.5 were...Ch. 7 - The following pedigree shows the inheritance of a...Ch. 7 - Autism is a neurological disorder thought to be...
Ch. 7 - Like the yellow Labrador retrievers featured in...Ch. 7 - Remember that Balancer chromosomes prevent the...Ch. 7 - Figure 7.14 shows examples of base substitutions...Ch. 7 - Figure 7.14a shows the mutagen 5-bromouracil 5-BU,...Ch. 7 - So-called two-way mutagens can induce both a...Ch. 7 - In 1967, J. B. Jenkins treated wild-type male...Ch. 7 - When a particular mutagen identified by the Ames...Ch. 7 - Prob. 18PCh. 7 - The Ames test uses the reversion rate His- to His...Ch. 7 - The mutant FMR-1 allele that causes fragile X...Ch. 7 - The physicist Stephen Hawking, famous for his...Ch. 7 - Aflatoxin B1 is a highly mutagenic and...Ch. 7 - In human DNA, 70 of cytosine residues that are...Ch. 7 - Bromodeoxyuridine BrdU is a synthetic nucleoside...Ch. 7 - Albinism in animals is caused by recessive...Ch. 7 - a. In Figure 7.22b, what can you say about the...Ch. 7 - Imagine that you caught a female albino mouse in...Ch. 7 - Plant breeders studying genes influencing leaf...Ch. 7 - In humans, albinism is normally inherited in an...Ch. 7 - a. Seymour Benzers fine structure analysis of the...Ch. 7 - a. You have a test tube containing 5 ml of a...Ch. 7 - Prob. 32PCh. 7 - The rosy ry gene of Drosophila encodes an enzyme...Ch. 7 - Nine rII- mutants of bacteriophage T4 were used in...Ch. 7 - In a haploid yeast strain, eight recessive...Ch. 7 - In Problem 24, you learned that Bloom syndrome is...Ch. 7 - The pathway for arginine biosynthesis in...Ch. 7 - In corn snakes, the wild-type color is brown. One...Ch. 7 - In a certain species of flowering plants with a...Ch. 7 - The intermediates A, B, C, D, E, and F all occur...Ch. 7 - In each of the following cross schemes, two...Ch. 7 - Prob. 42PCh. 7 - The following complementing E. coli mutants were...Ch. 7 - In 1952, an article in the British Medical Journal...Ch. 7 - Mutations in an autosomal gene in humans cause a...Ch. 7 - Antibodies were made that recognize six proteins...Ch. 7 - Prob. 47PCh. 7 - Prob. 48PCh. 7 - In addition to the predominant adult hemoglobin,...Ch. 7 - Most mammals, including New World primates such as...Ch. 7 - Humans are normally trichromats; we have three...
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