You compare two strands of mtDNA and discover that there are 3 differences in base pairs between them. Assuming that the mutation rate for the species that you are examining is 1 mutation every 20,000 years, how long ago did the two strands share a common ancestor? Write your answer in xx,Xxx format. These two strands shared a common ancestor years ago.

In a transformation experiment involving a recipientbacterial strain of genotype a- b-, the following resultswere obtained. What can you conclude about the locationof the a and b genes relative to each other?                                Transformants (%)Transforming DNA    a+ b-    a-b+       a+b+a+b-                            3.1       1.2         0.04a+b- and a-b+            2.4       1.4         0.03

High doses of caffeine interfere with the DNAdamage response in mammalian cells. Why then do yousuppose the Surgeon General has not yet issued an appro-priate warning to heavy coffee and cola drinkers? A typicalcup of coffee (150 mL) contains 100 mg of caffeine (196 g/mole). How many cups of coffee would you have to drinkto reach the dose (10 mM) required to interfere with theDNA damage response? (A typical adult contains about 40liters of water.)

B-C-A cannot be determined C-B-A C-A-B A-C-B

The accuracy of DNA replication in the human germ-cell line is such that on average only about 0.6 out of the 6 billion nucleotides is altered at each cell division. Because most of our DNA is not subject to any precise constraint on its sequence, most of these changes are selectively neutral. Any two modern humans picked at random will show about 1 difference of nucleotide sequence in every 1000 nucleotides. suppose we are all descended from a single pair of ancestors—Adam and Eve—who were genetically identical and homozygous (each chromosome was identical to its homolog). Assuming that all germ-line mutations that arise are preserved in descendants, how many cell generations must have elapsed since the days of Adam and Eve for 1 difference per 1000 nucleotides to have accumulated in modern humans? Assuming that each human generation corresponds on average to 200 cell-division cycles in the germ-cell lineage and allowing 30 years per human generation, how many years ago would this…

Using a laser beam, you isolated several R bands from human chromosomes. Answer the following questions What kinds of genes are present in R bands? Which isochors do you expect to be present in the R band? What class of interspersed repeats will be present in R bands? What class of tandem repeats do you expect to find in RG bands? Would you expect to find telomere sequences in some R bands?

Separation of very large DNA fragments Answer 1 Inbreeding Answer 2 Autosomal dominant disorder Answer 3 Y chromosome Answer 4 Both low and high copy number origins of replication Answer 5 DNA double-helix Answer 6 Linear vector Answer 7 Chain termination DNA sequencing chemical Answer 8 Amino acid sequence of insulin and chain termination DNA sequencing Answer 9 Alu and L1 (LINE) elements