Question

Expressed Sequence tags (ESTs) refer to?
A. Genes expressed as RNA
B. Polypeptide expression
C. DNA polymorphism
D. Novel DNA sequences

Answer 1

Hint: ESTs have become a tool to refine the predicted transcripts for those genes, which leads to the prediction of their protein products and ultimately of their function.

Complete Answer:
A short subsequence of a circular DNA sequence is an articulated sequence tag (EST) in genetics. ESTs can be used to classify transcripts of genes which are essential in genome exploration which confirm gene sequences. ESTs have been detected easily, with nearly 74.2 million ESTs already accessible in public databases.

Now, let us find the solution from the options-
- Expressed Sequence Tags(ESTs) are sequences of DNA (genes) encoded for protein synthesis as mRNA. These are included in the Project for Human Genome.
- One-shot sequencing of a replicated cDNA comes from an EST. Individual clones from a cDNA library are usually the cDNAs utilized for EST generation. Thus, option B is not the correct answer.
- The aim is to sequence DNA fragments that depict genes from various species expressed in specific cells , organs, or tissues, and use these "marks" to capture a gene by combining base pairs from a segment of chromosomal DNA. Thus, option C is not the correct option.
- A comparatively low-quality fragment which length is restricted by current technologies to around 500 to 800 nucleotides is the resulting sequence. As the clones comprise of DNA that is complement to mRNA, parts of expressed genes are represented by the ESTs. Thus, option D is not the correct option.

Thus, the correct answer is option (A) Genes expressed as RNA.

Note: The acquisition of ESTs provides details on the circumstances under which the relevant gene operates. ESTs provide adequate knowledge to allow specific probes to be developed for DNA microarrays that can then be used to establish profiles of gene expression.