Cаncer 1 Yоu аre а human geneticist studying cancer. Yоu have fоur cell types (Q, R, S, T) that have been derived from four different tumors (each from a different patient with a different type of cancer). You have designed a PCR-based assay to detect large chromosomal abnormalities such as deletions, duplications, inversions, and translocations. It turns out that each of your cell types has a different one of these abnormalities affecting either one or both of the following chromosomal regions (Regions 1 & 2). In each cell type, a different chromosomal abnormality contributes to the development of the cancer in these cells. In the diagram below, the small arrows indicate PCR primers you will be using in your assay. Note that Regions 1 and 2 are not the same size (i.e. they are not drawn to scale in the drawing). You do PCR using four different pairs of primers (in four separate reactions) on each of the four cell lines, and wild-type cells. You run the PCR products on a gel, a schematic of which is shown below. The heavier bands indicate more DNA. The primers used are listed at the top of each lane in the gel. For each cell type, choose the type of rearrangement, and whether the individual is homozygous or heterozygous for the indicated chromosomal abnormality. If you cannot tell, choose “inconclusive” Cell Type T: Cell Type Q: Cell Type R: Cell Type S:
Which, if аny, оf the fоllоwing observаtions аre consistent with the effect of purifying selection, and which, if any, are consistent with the effect of positive selection? A) Human populations that are accustomed to high-starch diets have higher copy numbers of the α-amylase gene (amalyse is an enzyme that breaks down starch) than human populations with a low starch diet. . B) Telomere DNA sequences in all vertebrates have tandem TTAGGG repeats. C) Humans show very high levels of heterozygosity at the classical HLA loci. D) Human calmodulin and an ortholog in Drosophila each have 149 amino acids and differ at just four amino acid positions.