Question

QUESTION 36

Consider two theoretical transposable elements in yeast, A and B. Each contains an intron and each transposed to a new location in the yeast genome. Suppose you then examine the transposons for the presence of the intron. In the new locations, you find that A has no intron but B does. From these facts, what can you conclude about the mechanisms of transposition for the two transposable elements?

A. A probably doesn't create a duplication of the host genome target sequence.

B. B probably makes a reverse transcriptase.

C. B probably makes a transposase.

D. B probably uses RNA as an intermediate in the transposition event.

E. A probably has inverted repeats at each end of the element.

Answer 1

Transposons: Transposable elements is a DNA sequence which has the ability to change its relative position within the genome of the single cell. These segments of DNA is found in all cellsand can jump from one place of a chromosome - a donar site to another target site which may be on the same chromosome or a different chromosomes. This jumping elements or transposable elements was first discovered in maize in 1940's by McClintock Barbara. Ty-1 likeelements in yeast are characterized by a +1 frameshift machanism which regulates Gag/Gag-Pol ratio and primary binding sites complementary to different tRNAs which initiate first-strand reverse transcription using tRNAimet as primer.

Answer: C.