Concept explainers
Neanderthal Hair Color The MCIR gene regulates pigmentation in humans (Sections 14.1 and 15.l revisited), .so loss-of-function mutations in this gene affect hair and .skin color. A person with two mutated alleles for this gene makes more of the reddish melanin than the brownish melanin, resulting in red hair and pa le skin. DNA extracted from two Neanderthal fossils contains a mutated MC1R allele that has not yet been found in humans, To see how the. Neanderthal mutation affects the function of the MC1R gene, Carles Lalueza-Fox and her team introduced the allele into cultured monkey cells (FIGURE 26.1 6).
FIGURE 26.16 MC1R activity in monkey cells transgenic for an unmutated MClR gene, the Neanderthal MC1R allele or the gene for green fluorescent protein (GFP). GFP is- not related to MC1R.
What purpose do the cells with the gene for green fluorescent protein serve in this experiment?
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Chapter 26 Solutions
Biology: The Unity and Diversity of Life (MindTap Course List)
- Neanderthal Hair Color The MC1R gene regulates pigmentation in humans (Sections 14.1 and 15.1 revisited), so loss-of-function mutations in this gene affect hair and skin color. A person with two mutated alleles for this gene makes more of the reddish melanin than the brownish melanin, resulting in red hair and pale skin. DNA extracted from two Neanderthal fossils contains a mutated MC1R allele that has not yet been found in humans. To see how the Neanderthal mutation affects the function of the MC1R gene. Carles Lalueza-Fox and her team introduced the allele into cultured monkey cells (FIGURE 26.16). FIGURE 26.16 MC1R activity in monkey cells transgenic for an unmutated MC1R gene, the Neanderthal MC1R allele, or the gene for green fluorescent protein (GFP). GFP is not related to MC1R. 1. How did MCR1 activity in monkey cells with the mutant allele differ from that in cells with the normal allele?arrow_forwardOriginal DNA AAG TAG ATC GAA TAT TAC Mutated DNA AAG TAG ATC GAC TAT TAC 2nd base in codon UCA Tyr Туг Ser Ser Ser Ser Pro Pro Pro Pro Thr Thr Thr Thr Ala Ala Ala Ala Cys Cys STOP STOP Trp Arg Arg Arg Arg Ser Ser Arg Arg Gly Gly Gly Gly Phe U Phe Leu Leu Leu Leu Leu Leu le lle lle Met Val Val Val Val STOP His His Gln Gin Asn Asn Lys Lys Asp Asp Glu Glu 3rd base in codon DUAGUCACUCAGUCAG C. 1st base in codonarrow_forwardPart B When a gene is duplicated resulting in two copies, there are three possible fates for the duplicate copy Sort each item to the appropriate bin. Potential to generate a new phenotype Most likely outcome for duplicated genes Pseudogene (Nonfunctionalization) 4 Both gene copies are required to carry out the functions of the original gene One gene copy is inactivated due to deleterious mutations Subfunctionalization Most interesting evolutionary outcome for duplicated genes Least likely outcome for duplicated genes Reset Help Neofunctionalizationarrow_forward
- Gene Interaction and Epistasis Hair color is due to the presence of melanin. There are two types of melanin produced by melanocytes. One is eumelanin, which is responsible for black (homozygous), brown (heterozygous), and blond (recessive) hair colors. The other is pheomelanin, which is responsible for red hair color. During melanin synthesis, MCR1gene converts pheomelanin to eumelanin. However, a variant of the MCR1 gene (MCR1variant), prevents this conversion. A cross between a blond-haired mother and a red-haired father produced 100% brown-haired children. When they came of age, one child married a double heterozygote, and both were blessed with 7 children; 2 with black hair, 2 with brown hair, 1 with blond hair, and 2 with red hair. Using the 7-step method, determine the genotypes of the P1, the F1, and the F2s. BOX your answers (if handwritten) or HIGHLIGHT your answers (if encoded). STEP 1: ________________________________________________________ STEP 2:…arrow_forwardONE OF THE ANSWER IS WRONG PLEASE HELP ME FIND THE RIGHT ANSWER Duplication of genes is an important evolutionary mechanism. As a result, many, cases are known in which a species has two or more identical genes. Suppose there are two genes - A and B - that specify production of the same enzyme. These two genes show autosomal recessive inheritance. An abnormal phenotype results only if an individual does not make any of that enzyme. Only one of these two genes needs to be functional in order to make the enzyme. What ratio of normal to abnormal progeny would result from a mating between two parents of genotype AaBb where A and B represent alleles that specify production of the enzyme, while a and b do not? Write your ratio like this - e.g 1:2 ratio - Suppose now there are three genes - A,B and C that specify production of this enzyme and again only one single functional allele is sufficient for a wild-type phenotype. How many of the possible phenotypes would be normal? Write your answer…arrow_forwardUnanswered As a hobby you propagate a population of worms. You notice that one worm is now clear instead of being tan. You trace down the mutation and discover that it is a single basepair deletion in a pigmentation gene. Explain how a single basepair deletion could result in a drastic mutant phenotype. Your answer Write your response here... ion onarrow_forward
- What phenotypes do you think a homozygous tra1hsn animal with a loss of function Egl-1 mutation would have.arrow_forwardThe skin pigment melanin is expressed differently according to exposure to sunlight, with a greater production of the molecule with greater exposure. However, the degree of production can never exceed the inherited genetic level. What evolutionary advantage would be gained from having this phenotypic range for skin pigmentation?arrow_forwardVariations in Phenotype Expression A genetic disorder characterized by falling asleep in genetics lectures is known to be 20% penetrant. All 90 students in a genetics class are homozygous for this gene. Theoretically, how many of the 90 students will fall asleep during the next lecture?arrow_forward
- One unexpected result of the sequencing of the human genome was the finding that mutations in a single gene can be responsible for multiple distinct disorders. For example, mutations in the RET gene can cause two different types of multiple endocrine neoplasias, familial medullary thyroid carcinoma, and Hirschsprung disease. How do you think mutations in a single gene can have such diverse effects?arrow_forwardMutation: Tan Body Pgeneration Phenotypes: Normal female X Tan male Fi generation Phenotvoe Females Males Total Ratio Normal Tan F, XF, Phenotypes: Normal female X Normal male F2 generation Phenotvoe Females Males Total Ratio Normal 8. 4. Tan 4 F Punnett square F. Punnett square Ths mutation is inhented aS 399Farrow_forward1. (a)genes with similar function orthologous genes paralogous genes pseudogenes all of these (b) insulin genes in human and cow orthologous genes paralogous genes pseudogenes all of thesearrow_forward
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