Question

Which retrotransposon makes up 15% of our genome and encodes its own reverse transcriptase enzyme for transposition?

A. L1 element

B. Alu sequence

C. latent HIV

D. bacterial transposons

Answer 1

The L1 element, a type of non-LTR retrotransposon known as LINES, makes up 15% of the human genome and can copy itself within the genome using the reverse transcriptase that it encodes.

Step-by-step explanation:

The retrotransposon that makes up 15% of our genome and encodes its own reverse transcriptase enzyme for transposition is the L1 element. These elements are a category of non-LTR retrotransposons known as LINES (Long Interspersed Nuclear Elements), and they play a significant role in the human genome. L1 elements are capable of copying themselves through a process involving the transcription of their RNA, followed by reverse transcription and integration of the cDNA back into the genome at a different location.

Unlike LTR retrotransposons and retroviruses, L1 elements lack long terminal repeats, but they are still essential for the transposition process. They contain genes flanked by 5' and 3' untranslated regions (UTRs) and provide the necessary enzymatic machinery, which includes reverse transcriptase, for their mobilization within the genome.