This video, we're going to briefly discuss molecular tools used to determine population size. And so, population sampling strategies involving molecular genetics can be used to estimate population size. And so the main idea here is that DNA samples can be acquired and sequenced from many different individuals in the population, and after analyzing those sequences, if the sampled individuals are deemed to be closely related, then the population size is likely small. Now, on the other hand, if after analyzing the sequences, the sampled individuals are deemed to be distantly related, then the population size is likely large. And so, notice down below in the image, we're looking at these two populations of this downy woodpecker.
On the left-hand side, what you'll notice is that the sample showed that the individuals are closely related, and that means that they have relatively low genetic diversity, and that implies a relatively small population size. Now, on the other hand, on the right-hand side over here, what you'll notice is that the sample shows quite high genetic diversity, indicating that these individuals are more distantly related, and that implies a large population size. And really that's the main idea of this technique. So we'll be able to apply this in our next video, and I'll see you there.