The melanocytes of wild -type (nonmutant) mice produce more pheomelanin than eumelanin. The result is a sandy -colored mouse. The mutated version of the Mc1r gene, however, triggers melanocyt es to increase the production of eumelanin, resulting in the dark coat -color phenotype.
- 1 How the mutant MC1R protein directly affects a rock pocket mouse coat color?
- 2 How does the wild type MC1R gene result in the light phenotype?
- 3 When the MC1R gene is turned on what happens to the color of the mice fur?
- 4 What is the significance of the MC1R gene in the evolution of dark colored mice?
- 5 How does the MC1R gene work?
- 6 What did they discover in the genes of the pocket mice was there a mutation?
- 7 How do silent mutations affect the structure and function of the protein?
- 8 What are the 3 main regions of the MC1R protein?
- 9 What type of mutation has occurred to produce the dark and light phenotypes?
- 10 How do scientists explain where the dark colored phenotype came from in the first place?
- 11 How is MC1R expressed in melanocytes?
- 12 Where does the MC1R gene come from?
- 13 Where is the MC1R protein found?
- 14 What does it mean when mutations occur randomly?
- 15 What can happen to the protein when there is a mutation in the DNA sequence?
How the mutant MC1R protein directly affects a rock pocket mouse coat color?
The amino acid changes in the MC1R protein may change the structure and function of the protein. This leads to increased production of eumelanin, which results in the dark color.
How does the wild type MC1R gene result in the light phenotype?
Wild type MC1R results to light phenotype The normal receptor requires a ligand for activating the G protein. The absence of the ligand will decrease the production of eumelanin, leading to a light phenotype due to the increase in pheomelanin production.
When the MC1R gene is turned on what happens to the color of the mice fur?
The color of a mouse’s fur is affected by the alleles they inherit for the MC1R gene. Mice that have two copies of allele 1 have the lightest fur, those with two copies of allele 2 have the darkest fur, and heterozygotes have intermediate fur color (though it is closer to the dark fur color).
What is the significance of the MC1R gene in the evolution of dark colored mice?
The mutated version of the Mc1r gene results in an increase in the production of eumelanin by melanocytes, resulting in the dark coat-color phenotype.
How does the MC1R gene work?
The MC1R gene provides instructions for making a protein called the melanocortin 1 receptor. This receptor plays an important role in normal pigmentation. The receptor is primarily located on the surface of melanocytes, which are specialized cells that produce a pigment called melanin.
What did they discover in the genes of the pocket mice was there a mutation?
Why did dark-colored rock pocket mice first appear in a population of light-colored rock pocket mice? They have a genetic mutation that affects their fur color. There is dark lava rock in the area where they live. Individuals change color to blend in with the environment.
How do silent mutations affect the structure and function of the protein?
Silent mutations occur when the change of a single DNA nucleotide within a protein-coding portion of a gene does not affect the sequence of amino acids that make up the gene’s protein. And when the amino acids of a protein stay the same, researchers believed, so do its structure and function.
What are the 3 main regions of the MC1R protein?
Three major MC1R ligands are α-MSH, ASIP, and βD3. The melanocortin α-MSH functions as a positive agonist to increase cAMP levels downstream of MC1R.
What type of mutation has occurred to produce the dark and light phenotypes?
Peppered moth melanism mutation is a transposable element. One of the most known examples of natural selection in action is the evolution of the peppered moth (Biston betularia), the rapid replacement of the light-colored form of the moth (typica) by a dark-colored form (carbonaria) (Fig. 1) during 1800s in Britain.
How do scientists explain where the dark colored phenotype came from in the first place?
The dark-colored mice arose in the population at location A by random mutation. The phenotype did not become more common because it did not afford a selective advantage to the mice. Use the data and what you have learned about evolution to explain how mutation is a random process, but natural selection is not random.
How is MC1R expressed in melanocytes?
MC1R is a receptor expressed in melanocytes that is activated by melanocortins such as α-MSH. Upon being stimulated, MC1R increases the levels of intracellular cAMP, which induces melanogenesis. In addition to constitutive pigmentation, facultative pigmentation induced by UV exposure is also controlled by MC1R.
Where does the MC1R gene come from?
What causes red hair? Red hair is a recessive genetic trait caused by a series of mutations in the melanocortin 1 receptor (MC1R), a gene located on chromosome 16. As a recessive trait it must be inherited from both parents to cause the hair to become red.
Where is the MC1R protein found?
MC1R is one of the key proteins involved in regulating mammalian skin and hair color. It is located on the plasma membrane of specialized cells known as melanocytes, which produce the pigment melanin through the process of melanogenesis.
What does it mean when mutations occur randomly?
In other words, mutations occur randomly with respect to whether their effects are useful. Thus, beneficial DNA changes do not happen more often simply because an organism could benefit from them.
What can happen to the protein when there is a mutation in the DNA sequence?
A missense mutation is a mistake in the DNA which results in the wrong amino acid being incorporated into a protein because of change, that single DNA sequence change, results in a different amino acid codon which the ribosome recognizes. Changes in amino acid can be very important in the function of a protein.