Question

Which of the following is a wrong statement regarding TESTCODE method?

(a) This is based on the nucleotide composition of the third position of a codon

(b) In practice, because genes can be in any of the six frames, the statistical patterns are computed for all possible frames

(c) It is implemented in the commercial GCG package

(d) It exploits the fact that the third codon nucleotides in a coding region fails to repeat themselves

I have been asked this question in exam.

This key question is from Gene Prediction in Prokaryotes in section Gene and Promoter Prediction of Bioinformatics

Answer 1

Correct option is (d) It exploits the fact that the third codon nucleotides in a coding region fails to repeat themselves

Explanation: In a coding sequence, it has been observed that this position has a preference to use G or C over A or T. By plotting the GC composition at this position, regions with values significantly above the random level can be identified, which are indicative of the presence of ORFs. This method exploits the fact that the third codon nucleotides in a coding region tend to repeat themselves.