Palm Beach State College Molecular Genetics Peer Responses


  • Read and evaluate at least two of your peer’s postings and compose substantial in-depth responses for both. 


Almost all proteins have an ideal temperature range and if the temperature is outside that range the protein denatures and the functionality is changed but in most cases the function of the protein is lost completely, and the proteins become biologically inactive (Urry et al., 2020). In the case of Siamese cats, the allele that codes for dark colored fur is very susceptible to heat or increased temperatures. The allele that controls how much melanin is produced for the fur in Siamese cats has a mutation that causes heat sensitivity and when the protein gets too hot it denatures and very little or none is produced causing the fur to turn a creamy, light ivory color instead of a darker black color. This heat sensitivity mutation causes the protein to function better, if at all, at specific temperatures (Urry et al., 2020). On some areas of a Siamese cats we see black fur, but the majority of the body is ivory. The feet, tail, ears, and face of Siamese cats all turn black. These areas tend to be the coldest areas as they get very little body heat. These areas are cooler and so the protein that controls fur color does not denature and so the black color is produced and seen in these areas. The cooler parts of the body have black fur while the center of the body, the belly, and the back of the cats are ivory because they are warmer as the majority of the body heat is produced and held in the belly and center of the body. These warmer sections of the body are ivory because temperature is high enough to denature the tyrosinase and make it no longer biologically functional (Todd & Kenyon, 2016). Now that it is not biologically functional the color is not produced, and the fur grows in ivory.


Todd, A. T., & Kenyon, L. S. (2016). HOW DO SIAMESE CATS GET THEIR COLOR? Exploring the role of proteins in molecular genetics. The Science Teacher (National Science Teachers Association).

Urry, L., Cain, M., Wasserman, S., Minorsky, P., & Orr, R. (2020). Modified Mastering Biology with Pearson eText — Access Card — for Campbell Biology (18-Weeks) (12th ed.) [E-book]. Pearson

VERSACHIA- Some mutations result in proteins that function well at one temperature but are nonfunctional at a different (usually higher) temperature. Siamese cats have such e “temperature-sensitive” mutation in a gene that makes dark pigment for fur. The mutation results in a breed’s distinctive point markings, and lighter body color. Using information from this chapter, explain the pattern of cat’s fur pigmentation.

A point mutation has more chance to be a silent one as one nucleotide can probably be substituted by one coding for the same amino acid, but a frame shift means at least two nucleotides are changed which has a less probability to be substituted by two others coding for the same nucleotide. This is why frame shift has more chance to give a non-functional protein. The DNA sequence of a gene can be altered in a number of ways. Gene mutations have varying effects on health, depending on where they occur and whether they alter the function of essential proteins. The types of mutations include silent mutation, Missense mutation, and Nonsense mutation. 

References: Tan, G., Chen, M., Foote, C., & Tan, C. (2009, September). Temperature-sensitive mutations made easy: Generating conditional mutations by using temperature-sensitive inteins that function within different temperature ranges. Genetics. Retrieved June 25, 2022, from…

Calculate Price

Price (USD)