Question

Which is incorrect with reference to transposon?

• A. It is known as jumping genes
• B. It was first discovered by Barbara McClintock
• C. Retrotransposons can move through RNA intermediates
• D. 2/3 of human genome is made up of transposons

Hint:

• Transposons ("Jumping Genes") Mobile DNA elements.
• Discovered by Barbara McClintock in maize.
• Class I (Retrotransposons) Move via an RNA intermediate (copy-and-paste). E.g., LINEs, SINEs, LTR retrotransposons.
• Class II (DNA Transposons) Move directly as DNA (cut-and-paste or replicative transposition).
• Transposons constitute a large fraction of many eukaryotic genomes (e.g., ~45-50% in humans).

Answer 1

The Correct Option is D

To determine which statement about transposons is incorrect, we need to assess each option:

1. It is known as jumping genes: Transposons are indeed referred to as "jumping genes" because they can change their position within the genome.
2. It was first discovered by Barbara McClintock: Barbara McClintock discovered transposons in maize in the 1940s, winning a Nobel Prize for her discovery.
3. Retrotransposons can move through RNA intermediates: Retrotransposons do move via an RNA intermediate, which involves transcription into RNA and reverse transcription into DNA.
4. 2/3 of human genome is made up of transposons: This is incorrect. While a significant portion of the human genome consists of transposons, it is not as high as two-thirds.

Therefore, the statement "2/3 of human genome is made up of transposons" is incorrect.