Correct option is A
Explanation:
- LINEs (Long Interspersed Nuclear Elements) are a type of retrotransposon present in the human genome.
- They are autonomous transposons, meaning they can move independently within the genome.
- Studies have shown that LINEs preferentially insert into AT-rich regions of the genome, making option (a) correct.
- AT-rich DNA is less structurally constrained than GC-rich DNA, making it more favorable for LINE insertions.
Thus, the correct statement about LINEs is that they preferentially localize to AT-rich DNA (option a).
Information Booster
- LINEs make up approximately 17% of the human genome.
- The most common LINE family in humans is LINE-1 (L1), which is still active in transposition.
- LINEs encode two proteins: ORF1p (RNA-binding protein) and ORF2p (endonuclease and reverse transcriptase), which enable independent movement.
- LINEs insert preferentially into AT-rich regions because these regions are less structured and more accessible.
- LINEs contribute to genome evolution by causing mutations, rearrangements, and new regulatory elements.
- Unlike SINEs (Short Interspersed Nuclear Elements), LINEs do not require external machinery for transposition.
- LINE activity has been linked to certain diseases, such as cancer and genetic disorders.
Additional Information
Option (b) "LINEs cannot transpose independently" is incorrect
→ LINEs do transpose independently because they encode the necessary enzymes (reverse transcriptase and endonuclease) for their mobilization.Option (c) "By parasitizing on the SINE element transposition machinery, LINEs can attain very high copy number" is incorrect
→ It is actually the opposite. SINEs (like Alu elements) depend on LINE machinery for transposition, not the other way around.Option (d) "The Alu family is the most prominent LINE family in terms of copy number" is incorrect
→ Alu elements belong to the SINE family, not LINEs. They are the most numerous transposable elements in the genome, but they do not belong to the LINE category.
