Question

C value refers to the DNA content in haploid cell and has no correlation with the complexity of the organism. Which of the following explains this C value paradox?

• A. Polyploidy
• B. Mutations
• C. Non coding DNA
• D. Coding DNA

Hint:

Remember that the term "C-value" stands for "constant value," referring to the consistent amount of nuclear DNA found in gametes of a given species.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
The "C-value" is the amount of DNA in a haploid genome.
The C-value paradox describes the lack of correlation between an organism's genome size and its morphological complexity.

Step 2: Detailed Explanation:
Intuitively, one might expect complex multicellular eukaryotes to require larger genomes than simpler organisms.
However, many simple organisms (such as certain amoebae or plants) have genomes that are several orders of magnitude larger than the human genome.
This paradox is explained by the presence of large amounts of non-coding DNA.
In many large genomes, structural protein-coding genes make up less than \(2%\) of the total DNA.
The remaining genomic space is occupied by repetitive, non-coding elements, including transposable elements, pseudogenes, introns, and highly repetitive satellite DNA sequences.
Variations in genome size between species are primarily driven by differences in the accumulation and deletion of these non-coding elements, rather than differences in gene number.

Step 3: Final Answer:
The C-value paradox is explained by the presence of Non coding DNA.