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UESTION 9 You identify an RFLP in mice by digesting genomic DNA with Hind III en

ID: 100650 • Letter: U

Question

UESTION 9

You identify an RFLP in mice by digesting genomic DNA with HindIII enzyme and radiolabeling a piece of probe DNA. Southern blot analysis shows that the probe detects a 2-kb fragment in one strain of mice and a 4-kb fragment in another strain of mice. The two mice strains are crossed to produce an F1 generation. Two F1siblings are mated to produce a dozen F2 progeny. You isolate genomic DNA from several F1 and F2 individuals, digest with HindIII, and perform a Southern blot with the same probe.

How many bands would be seen in the Southern blot of an F1 individual?

two

four

one or two

one

three

Q2-

Ampicillin resistance is to ampR as _____ is to lacZ.

gancyclovir

cleavage of X-gal

penicillin resistance

G418

Bt toxin

Q3-

A.

two

B.

four

C.

one or two

D.

one

E.

three

Explanation / Answer

1.a.As   probe detects a 2-kb fragment in one strain of mice and a 4-kb fragment in another strain of mice.Thus 2 bands would be seen in the Southern blot of an F1 individual.

2.b. The antibiotic & Xgal markers provide a selection scheme for recombinant bacterial colonies, as follows. First, only bacterial colonies that contain a plasmid-borne antibiotic-resistance gene can grow at all. Second, of those that grow, only those whose plasmids carry a functional LacZ in the polylinker can metabolize Xgal.