Case one review the gel results of the dna profiles of the...

Case one: Review the gel results of the DNA profiles of the two example elephants with the four markers. For each marker how do you know if the individual is homozygous for a marker? There are no bands on the gel for the marker. There is only one band on the gel for the marker. There are two bands on the gel for the marker.

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Transcript

00:01 So in this question, we're looking at pcr tests.

00:05 And it looks like you're doing a test and you have a couple of different strands here.

00:10 And it says real quick that pcr tests, the way that a pcr test looks right, you have, this is your top, your bottom, right? and you have these different columns.

00:28 And along these columns, you have bands, right? and you have the large molecules at the top and small molecules at the bottom.

00:46 So when a pcr test fails, if you have a molecule, a dna strand that was supposed to be cut here and didn't or failed or failed to get cut all the way, right? you should have this, these three bands, but you only end up with two because this.

01:10 This one that was supposed to be down here actually got stuck up here because it didn't get cut right.

01:16 Right.

01:17 And that would be a fail.

01:18 That would be a pcr fails.

01:21 So pcr fails.

01:27 How do i put this? pcr fails when large molecules fail to cut right.

01:48 Right.

01:50 You can't have a fail where you have like three lines instead of two, right? you can't have more lines.

02:00 So you can't have a fail with more lines, only less, right? kind of like you can't have a false positive on a pregnancy test.

02:17 You can, but it's like it's just so incredibly rare...