Question

draw a southern blot in which genomic DNa frow WW rabbits, Ww rabbits pink, and ww rabbits white has been digested with EcoRI and hybridized to probe A

3. You have discovered a coat color gene ("W" gene) in rabbits that has two alleles, W and w. Rabbits that are homozygous for W (WW) are red. white. Heterozygous rabbits (Ww) are pink. Rabbits that are homozygous for w (ww) are You have also identified a DNA sequence of about 100 base pairs ("probe A") that identifies a 10kb EcoRI fragment in a true-breeding line of rabbits that are red. The same probe identifiesa Skb EcoRI fragment in a true-breeding line of rabbits that are white. When you breed the red rabbits with the white rabbits, you get pink progeny, and the DNA "probe A" described above identifies BOTH a 10kb EcoRI fragment AND a 5kb EcoRI fragment in genomic DNA from the pink rabbits. You can conclude that probe A is detecting a polymorphic region of the genomic DNA that has two alternate alleles: one we will call A as a designation for the RFLP "allele" you originally found in white rabbits and the other we will call A° as a designation for the RFLP "allele" you originally found in the red rabbits. You have identified a second DNA sequence of about 130 base pairs ("probe B") that identifies 7kb EcoRI fragment in the true-breeding red rabbits and an 11kb EcoRI fragment in the true- breeding white rabbits. We'll call the RFLP allele from the red rabbits B' and the RFLP allele from the white rabbits B". Genomic DNA from pink rabbits shows both the B'and the 8 EcORI fragments (detected with probe B). Draw a Southern blot in which genomic DNA from WW rabbits (red), Ww rabbits (pink), and ww rabbits (white) has been digested with EcoRI and hybridized to "probe A" Show the bands detected with probe A in each lane of the gel (genotype of the genomic DNA is shown below each lane). Identify the size of each fragment to the left of the gel (under kb). Write the coat color phenotype below each W genotype. A. kbGel origin

Answer 1

5. A. Southern blot of ribbit DNA digested with EcoRT tbridized to "probe A and you Red Probe A identfies as1oKb Eoki fragment Probe A. iderdifies both lOkb and s Kb EcoRI tra Probe A identifies kb ragment hel onigin Kb 5kb (red) (pink) (whib)