Describe the basis for chromosome mapping in the Hfr x F⁻ crosses.

Video transcript

Hi, everyone. Let's take a look at the following practice problem together. The process of conjugation does not occur between. So, conjugation, it's the combining of two bacteria in order to exchange genetic material. Now, in order for that to occur, two criteria must be met. The first is that one of the cells must contain the F factor or the fertility factor. And the second criteria is the other cell must not have the F factor. And so let's take a look at our possible choices and we'll see that both A and B tell us the same thing. And F plus cell combining with an F minus sell right away, we can eliminate them just because we know we can't have two correct answers. But conjugation does occur in these pairings. The F plus cell has the F factor, the F minus cell lacks it. Now D the H F R and F minus sell the HFR is a high frequency recombination. Sell, it does contain the F factor and it's located on the chromosome. And so in this instance, conjugation will occur. One of the cells has the F factor, the HFR and the F minus lacks it. So we're left with C as our correct answer. And so this is an HFR cell with the F factor and an F plus cell with the F factor. And so conjugation will not occur in this pairing. Alright, everyone, I hope you found this helpful and I'll see you for the next practice problem.