In Module 35.3, you learned that Norway rat offspring whose mothers don't interact much with them grow up to be fearful and anxious in new situations. Suggest a possible ultimate cause for this link between maternal behavior and stress response of offspring. (Hint: Under what circumstances might high reactivity to stress be more adaptive than being relaxed?)

Question

Accepted Answer

Hi everyone. Welcome back, Let's look at our next question. It says the fruitless gene among male fruit flies encodes a protein that stimulates a suite of genes that are responsible for courtship behavior. Example of these courtship behaviors include tapping the female's abdomen with their foreleg and vibrating one of their wings? What could result if a male fruit fly has a mutated version of the fruitless gene? Well, as our question talks about, and as we can recall from our content, video fruitless, the fruitless gene determines that courtship behavior in fruit flies and it actually has a sex specific alternate splicing. So in male fruit flies, after the gene is translated and spliced, you have a different product than in the female fruit flies, where it's spliced differently. So same gene but different splicing, so different protein product and male versus female fruit flies. So that's why a question specifically asked us about male fruit flies, because you have a different version of the gene in the two sexes. So, in the male fruit flies, the male specific splicing results in male courtship behavior. This is a fixed action pattern. That's a series of actions that are encoded genetically, their inborn, they're not learned and they don't change over time. So these courtship behaviors consists of an innate, fixed action pattern resulting from male specific, slightly splicing of the fruitless gene. So that's what we're going to be interested in. Since our question asked us about the result in male fruit flies and a mutation of this gene. Just for our own curiosity. The female specific splicing results in no courtship behavior, but that they're receptive to mating with males, but that does give us a little clue as to what might be one of the results of mutating the male fruitless stream. So since we have this fixed action pattern with these various steps encoded by this fruitless gene, Male fruitless gene, we can kind of have one of two results depending on what kind of mutation. How much is the gene affected? So if it's mutated enough and affected enough, you see similar results as to the female specific splicing, you might see no courtship behavior at all. A complete disruption in that fixed action pattern. Or if it's a smaller mutation, a different mutation, you could see a disruption this courtship behavior such that males court other males. So you can kind of have two different results again, depending on what kind of mutation and how extensive mutation. So let's look at our answer choices here and let's note that we have a choice D. Which is both A and C. So Choice A. Says the male fruit fly will not exhibit any courtship behavior as we spoke. That can be a result of a mutation in this gene. So we'll just mark that since we do have one answer choice that has more than one possibility. Choice B says the male fruit fly will turn into a female fruit fly. Well, this is not the correct answer. The males or females remain uh anatomically male or female. It just affects their courtship behaviors or mating behaviors. So Choice B. Is incorrect. Choice C. Says the male fruit fly will court other mayor fruit flies? And as we discuss, that is a possibility of a mutation in that fruitless gene, so we have A and C. Both being correct. So our answer is D. Both A and C. So again, the fruitless gene among male fruit flies encodes a protein responsible for courtship behavior. What could result if a male fruit fly has a mutated version of fruitless gene? Choice D. Both A and C. Either the male fruit fly will not exhibit any any courtship behavior or the male fruit fly will court other male fruit flies. See you in the next video.

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Key Concepts

Maternal Behavior

Stress Response

Evolutionary Adaptation