A small population of deer living on an isolated island is sep...

Question

A small population of deer living on an isolated island is separated for many generations from a mainland deer population. The populations retain the same number of chromosomes but hybrids are infertile. One chromosome (shown here) has a different banding pattern in the island population than in the mainland population.

Describe how the banding pattern of the island population chromosome most likely evolved from the mainland chromosome. What term or terms describe the difference between these chromosomes?

Comparison of mainland and island deer chromosomes showing different banding patterns and centromere positions.

Describe how the banding pattern of the island population chromosome most likely evolved from the mainland chromosome. What term or terms describe the difference between these chromosomes?

Accepted Answer

Welcome back, everyone. Let's look at our next question. In two populations of birds. The first population has chromosomes with light bands, alternating with dark bands while the second population has chromosomes with only light bands. Which of the following statements is therefore true choice. A the second population has more heterochromatin than the first population. B. The first population has more euchromatin than the second population to ac. The first population has more heterochromatin than the second population or choice d the 1st and 2nd populations have the same amount of heterochromatin and euchromatin. Well, when we talk about chromosomes having light and dark bands, we're talking about that technique, we can recall called gua staining where Chromos chromosomes are stained with a stain that differentiates between heterochromatin and euchromatin, as we can see in our answer choices. And in general, the dark bands r heterochromatin, which is that more condensed form of chromatin, it tends to be a rich which is why it takes up more of the stain and causes these dark bands to form. The lighter bands are generally made up of euchromatin, which is the less condensed version and is GC rich in general. So with those facts in mind, let's look through our answer choices. We see that the first population has light and dark bands alternating. So that would mean that it has both heterochromatin and euchromatin. So I'm just noting that on top of where it says first population and the second population has chromosomes with only light bands. So we would say that to be expected to have only U chromatin. So let's look at our answer. Choices. Choice A says the second population has more heterochromatin than the first population. Well, this is not correct because the second population has only light bands and heterochromatin is associated with dark bands. Choice B says the first population has more U chromatin than the second population. We can eliminate that also because the first population has both hetero and euchromatin. Whereas the second population has only euchromatin, then choi says the first population has more heterochromatin than the second population. And that would be our answer because the second population shows only these light bands and therefore really doesn't have much heterochromatin at all. So the first population definitely has more with its alternating light and dark bands. And finally, the last choice D says that both populations have the same amount of heterochromatin and euchromatin, but that's obviously not correct or they would have the same kind of banding. So again, the statement that is true based on the information we're given here is choice C the first population has more heterochromatin than the second population. See you in the next video.

Key Concepts

Chromosomal Variation

Speciation

Genetic Drift

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