molecular biology

[soniasunny111]

i need help……….. 😯

The following gel diagram shows the pattern of bands observed in a Southern blot for three tightly linked SSR molecular markers in and flanking the p16 gene in a family in which familial melanoma is found. Mutations in p16 are known to be associated with this cancer. Shown are an affected father, an unaffected mother, and an affected son. The bands A1 and A2 are for one SSR, with alleles A1 and A2, and the bands B1 and B2 are for another SSR, with the alleles B1 and B2. The p16+ and p16 bands are for the SSR for p16, where the wild type p16+ allele yields a band 1.0kb larger than the p16 mutant. The blot was probed with a fragment from each of the SSR markers so that all three could be visualized in the same blot. The order of the genes along the chromosome arm is centromere–B–p16–A–telomere.

a. Which SSR alleles are linked with p16?

b. If DNA from the son’s tumor cells were assayed, describe the SSR pattern that would be expected if the tumor cells had lost the p16+ bearing chromosome. Justify your answer.

c. Describe the SSR pattern that would be expected for the son’s tumor cells if the cells had undergone mitotic recombination in the centromere–B interval. Justify your answer.

d. Describe the SSR pattern that would be expected for the son’s tumor cells if the cells had undergone mitotic recombination in the B–p16 interval. Justify your answer.

e. Describe the SSR pattern that would be expected for the son’s tumor cells if a new nonsense mutation had occurred in the p16+ allele. Justify your answer.

f. Describe the SSR pattern that would be expected for the son’s tumor cells if gene conversion turned the p16+ allele into the p16 allele. Justify your answer.

[canalon]

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