Question

Expressed Sequence Tags (ESTs) refers to:

• A. Genes expressed as RNA
• B. Polypeptide expression
• C. DNA polymorphism
• D. Novel DNA sequences

Answer 1

The Correct Option is A

In this question, we need to identify what Expressed Sequence Tags (ESTs) refer to from the given options.

Expressed Sequence Tags (ESTs) are short sub-sequences of cDNA (complementary DNA) sequences. They are instrumental in identifying gene transcripts, as they are derived from mRNA (messenger RNA). This means ESTs represent the parts of the genome that are actively being transcribed into RNA. Therefore, the correct answer is Genes expressed as RNA.

Let's examine each option:

• Genes expressed as RNA: This is the correct option. ESTs are derived from mRNA, thus representing the genes that are being expressed in the form of RNA.
• Polypeptide expression: This is incorrect. ESTs are related to RNA expression rather than being directly related to polypeptide or protein expression.
• DNA polymorphism: This is incorrect. DNA polymorphisms refer to variations in DNA sequences between individuals, whereas ESTs specifically represent sequences that are transcribed into RNA.
• Novel DNA sequences: This is incorrect. While ESTs can help in discovering new genes, they are not novel DNA sequences themselves; they are existing sequences that are transcribed into RNA.

In conclusion, ESTs provide insight into which parts of genes are expressed in the form of RNA, aiding in understanding gene expression patterns and assisting in gene discovery.