Question

Which of the following is untrue regarding expressed sequence tags (ESTs)?

(a) One of the high throughput approaches to genome-wide profiling of gene expression is sequencing ESTs

(b) They are short sequences obtained from cDNA clones

(c) They serve as short identifiers of full-length genes

(d) They are typically in the range of 800 to 900 nucleotides in length

This question was posed to me in a job interview.

This question is from Sequence topic in chapter Functional Genomics & Proteomics of Bioinformatics

Answer 1

Right option is (d) They are typically in the range of 800 to 900 nucleotides in length

Explanation: ESTs are typically in the range of 200 to 400 nucleotides in length obtained from either the 5’end or 3’end of cDNA inserts. Libraries of cDNA clones are prepared through reverse transcription of isolated mRNA populations by using oligo (dT) primers that hybridize with the poly (A) tail of mRNAs and ligation of the cDNAs to cloning vectors.