Reading 12

Question 1

What are the two unique and characteristic properties of retroviral replication?

Answer 1

-revere transcription of viral DNA to RNA
-integration of the newly synthesized DNA into the genome of the infected cell

Question 2

What is an ‘endogenous retrovirus’?

Answer 2

a provirus that has been transmitted to offspring

Question 3

How is an endogenous retrovirus transmitted to offspring?

Answer 3

-The latter property gives the means for retroviruses to colonize the germ line which will inherit the provirus formed as an endogenous retrovirus

Question 4

What does the abbreviation “LTR” stand for?

Answer 4

-Long terminal repeats

Question 5

What is meant by the term “solo” LTR?

Answer 5

-when 2 long terminal repeats recombine which lead to the formation of solo LTRs

Question 6

True or False: Endogenous retroviruses have been found in all vertebrates studied to date?

Answer 6

-True

Question 7

True or False: The vast majority of endogenous retroviruses are active

Answer 7

-False

Question 8

How much (what percentage) of the human genome is derived from endogenous retroviruses?

Answer 8

-7%

Question 9

What are at least two compelling lines of evidence that suggest that endogenous retroviruses from the HERV-K lineage have formed within the last 200,000 years?

Answer 9

-the identity of the LTRs and the open reading frames
-these are not fixed in the human population

Question 10

Endogenous retroviruses show a significant tendency to recombine. Name at least two of these mechanisms, and what a potential consequence could be to the host genome?

Answer 10

-mechanisms: recombination of the 3 and 5 LTRs
-consequences: solo LTRs, deletions or rearrangements of DNA