What genetic changes take place during speciation?

Question

Accepted Answer

Hi, everyone. Let's look at our next question. It says which of the following types of genetic changes can cause polyp Lloyd ization leading to speciation. So let's start by recalling what politization is up here. So that would be increasing the number of chromosomes in an organism. Cells. Obviously, usually each species has a designated number of chromosomes. But we can have a cases where you end up changing that number of chromosomes and that occurs through kind of two main, one of two main ways either through mutations, particularly errors and cell division. So imagine our cell um during mitosis, excuse me, during mitosis. Prior to reproduction, we have all our chromosomes lined up in the middle of the cell. And instead of the homologous pair being divided one to each daughter cell, imagine if both of the homologous pair end up on one side of that dividing cell. So you end up with a daughter cell that has an extra chromosome, then also hybridization of two different species with a different number of chromosomes can end up with extra chromosomes in some of the daughter cells. So let's look at our answer choices noting that we do have choice d all of the above. So there is the potential for more than one correct answer. Well, right away, we see choice A is chromosomal mutation, which we know is a genetic change. And this can lead to speciation. Because if you have offspring with an extra chromosome, they might well be reproductively isolated from the parent species, they might not be able to produce fertile offspring with the parent species due to that extra chromosome or chromosomes. But if they're able to reproduce with other polyp Lloyd organisms, then that may lead to the development of a new species that no longer can contribute with the parent species. Now, let's look at our other answer. Choices again, we won't choose that as our answer. Since we do have the potential of that D, all of the above choice B says single nucleotide changes. Well, this would be mutations to a single base pair. So that is pretty unlikely to lead to polyp lionization. You're just changing one base pair that's not going to lead to having a whole extra chromosome or chromosomes. So that would not be our answer. And since choice B is not correct, we can cross out choice D, all the above that can lead us to go ahead and choose choice as our answer. But just to be thorough, we'll take a look at that last answer. Choice, choice, see gene duplication. So if you duplicate an entire chain and end up with two copies um that can end up changing the expression or uh cause an evolution of new gene function. Obviously can have a pretty big effect when you have two copies of an entire gene. But that's just one gene on a chromosome that's not going to lead to multiple copies of that chromosome being in being in an offspring cells. So choice C would not be alright. Correct answer. So again, which of the following types of genetic changes can cause politization leading to speciation. And that would be choice a chromosome mutation. See you in the next video.

What genetic changes take place during speciation?

Key Concepts

Speciation

Genetic Divergence

Reproductive Isolation

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