A scientist notices that the fur on the paws, nose, and ears of Himalayan rabbits is dark brown, whereas the fur on the rest of the animal's body is white. The scientist removes a section of skin from a Himalayan rabbit's ear and cultures the follicle cells. When cells are exposed to cold temperatures, they produce a specific pigment molecule. When the same cell is exposed to higher temperatures, it stops producing the pigment molecule. Which of the following best describes the scientist's experiments?
A) Temperature influences gene expression for fur color expression in Himalayan rabbits.
B) When kept at higher temperatures, follicle cells from Himalayan rabbits die.
C) During the breeding season, Himalayan rabbits use fur color to communicate fitness.
D) Temperature changes the structure of the pigment molecules produced by Himalayan rabbit follicle cells.
VerifiedHint: Consider the relationship between temperature and gene expression. How temperature affects the production of melanin, the pigment that gives fur its color
Complete Step-by-step Answer: The experiment conducted by the scientist demonstrates that the expression of the gene responsible for fur color in Himalayan rabbits is influenced by temperature. When the follicle cells from the rabbit's ear were exposed to cold temperatures, they produced the pigment molecule responsible for dark fur. However, when the cells were exposed to warmer temperatures, they stopped producing the pigment molecule. This suggests that the gene responsible for fur color is only active at cooler temperatures.
This phenomenon can be explained by the fact that Himalayan rabbits have a temperature-sensitive enzyme involved in melanin synthesis. This enzyme is active only at temperatures below 15°C (59°F). As a result, the enzyme is only active in cooler parts of the rabbit's body, such as the paws, nose, and ears, which are more exposed to the environment and tend to lose heat more quickly. In warmer parts of the body, such as the trunk, the enzyme is inactive, and no melanin is produced, resulting in white fur.
This temperature-sensitive enzyme is an example of how gene expression can be regulated by environmental factors. In this case, temperature plays a crucial role in determining the fur color of Himalayan rabbits.
Hence the Correct Answer is Option A
Additional Information: Himalayan rabbits are not the only animals that exhibit temperature-dependent fur color. Other examples include Siamese cats and certain species of lizards. In these animals, fur or skin color can change in response to changes in temperature, helping them to camouflage themselves or regulate their body temperature.
Note: This experiment is a classic example of how gene expression can be influenced by environmental factors. It also highlights the importance of temperature in regulating biological processes.
