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
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- 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_forwardYou are a studying the genetic basis of horn color in unicorns. Gene C determines the color of pigment destined for the horn by converting a pink precursor into a purple pigment. C- individuals make purple pigment whereas cc individuals accumulate pink precursor. Gene D ensures the deposition of the pigment into the horn cells, such that D- individuals have a colored horn (purple or pink), whereas dd individuals have a white horn. You breed two purple horned unicorns to each other (CcDd). Assuming Gene C and Gene D are unlinked, what is the probability that the baby unicorn has a purple horn? Please express your answer to 2 decimal places (e.g. 0.69).arrow_forwardOriginal DNA Sequence: TACAC CTTGG CGACGACT... MRNA Sequence: Amino Acid Sequence: Mutated DNA Sequence #5 TACACCTT G G GACGACT... (Highlight the change) What's the mRNA sequence? What will be the amino acid sequence? Will there likely be effects? What type of mutation is this? 1. Which type of mutation is responsible for new variations of a trait? 2. Which type of mutation does not result in an abnormal amino acid sequence? 3. Which type of mutation stops the translation of an mRNA molecule? NOarrow_forward
- What type of mutation is this? 1. Which type of mutation is responsible for new varia tions of a trait? Which type of mutation does not result in an abnormal amino acid sequece? Which type of mutation stops the translation of an mRNA molecule? 2. Sickle Cell Anemia Sickle cell anemia is the result of a type of mutation in the gene that codes for part of the hemoglobin molecule Hemoglobin carries oxygen in your red bloods cells. The mutation causes these red blood cells to become stife sickle-shaped when they release their oxygen. The sickled cells tend to get stuck in blood vessels, causing poin ond increased risk of stroke, blindness, damage to the heart & lungs, and other conditions. Analyze the DNA strands below to determine what amino acid is changed AND what type of mutation occurred Normal hemoglobin DNA A G TC Normal hemoglobin mRNA val• Hisolelo thr•proo Gll Normal hemoglobin AA sequence CA cGT AG A CTGAGG AC AC Sickle cell hemoglobin DNA Sickle cell hemoglobin mRNA Sickle cell…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_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
- Part 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_forwardWhat phenotypes do you think a homozygous tra1hsn animal with a loss of function Egl-1 mutation would have.arrow_forwardFigure illustrates albinism in two different species. Describetwo other genetic disorders found in both humans and animals.arrow_forward
- The 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_forwardOne 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_forward
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