Concept explainers
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?
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- 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?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_forwardSynpolydactyly is an abnormality characterized by webbing between partially or completely duplicated fingers or toes (Figure 18.15). The same mutations that cause the human phenotype give rise to a similar phenotype in mice. In what family of genes do you think these mutations occur?arrow_forward
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- The disease called phenylketonuria (PKU) is a recessive disorder in humans that is due to a loss-of-function mutation involving the gene that encodesphenylalanine hydroxylase. Some people with the disorder carrya point mutation that causes the loss of function, whereas otherindividuals have been shown to have a deletion of the entire gene. Explainhow you could use fluorescence in situ hybridization to distinguish apoint mutation from a deletion. Describe your expected results.arrow_forwardSome genes evolve more rapidly than others. But how can this be demonstrated?arrow_forwardA molecular geneticist hopes to find a Gene in human liver cell that codes for an important blood-clotting protein,he knows that the nucleotide sequence of a small part of the Gene is GTGGACTGACA.briefly explain how to obtain genearrow_forward
- A molecular geneticist hopes to find a gene gene in human liver cells that codes for an important blood clotting protein. He knows that the nucleotides sequence of a small part of the gene is GTGGACTGACA. briefly explain how to obtain the desired genearrow_forwardFriedreich ataxia (FRDA) is an autosomal recessive, neurodegenerative disease that causes a lack of voluntary coordination of muscle movements. Affected individuals are homozygous for an unusually large number (expansion) of repeats of a trinucleotide sequence (GAA) in the first intron of the X25 gene. Unaffected individuals typically have between 7 and 38 repeats of the trinucleotide (GAAGAAGAAGAA…). FRDA patients have anywhere from 66 to over 1,700 repeats. To understand how the GAA trinucleotide expansion leads to FRDA, researchers looked at X25 gene expression by extracting RNA from affected and unaffected patients and doing a northern blot analysis (see the figure below): In panel “a,” the researchers used a probe to detect X25 mRNA. In panel “b,” the researchers used a probe on a duplicate of the original blot to detect human GAPDH mRNA (GAPDH is an enzyme involved in glycolysis). The sample labeled “YR” is mRNA from yeast cells that was used as a control. Explain…arrow_forwardNeed answer ASAP.arrow_forward
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