Here's another question taken from "Concepts of Genetics," Klug et al (10ed), revolving around a paternity test. PCR and a Southern blot were carried out in order to determine whether 3 chimpanzees (lanes 3, 4, 5 in the blot below) were the "legitimate" offspring of 2 potential parents (lanes 1 and 2).
The question makes a point of saying that the primers used to bind to the chimp DNA originates from humans, and that they "flank highly polymorphic sites in human DNA that result from variable numbers of tandem nucleotide repeats." My first question is what exactly does "flanking" mean in this context? It sounds to me like the human DNA "mirrors" the chimp DNA, and so makes it good enough to use as a primer, but I'm not sure.
I've come across a few other examples not in the text about how to infer whether a potential parent is indeed a parent based on whether the offspring's lane contains bands found in both the maternal and paternal lanes, which leads me to believe I can rule out the chimp in lane 5.
I'm given five answers to choose from to decide which of the offspring, if any, are legitimate:
- A only
- A and B only
- Not enough data; more polymorphic sites should be examined
- No conclusion can be made because "human" primers were used
Main questions: Does that fact that we're using human DNA as primers cause any problems? Do we know enough from this blot to determine paternity?