Question

When a sequence is generated from ____ ends of a single clone, the distance between the two opposing fragments of a clone is fixed to ________ meaning that they are always separated by a distance defined by a _____ length (normally 1,000 to 9,000 bases).

(a) both, an uncertain range, clone

(b) one, an uncertain range, clone

(c) both, a certain range, clone

(d) both, a certain range, gene

This question was addressed to me in an international level competition.

My question is taken from Genome Sequence Assembly topic in division Genome Mapping, Assembly and Comparison of Bioinformatics

Answer 1

The correct answer is (c) both, a certain range, clone

To explain: A commonly used constraint to avoid errors caused by sequence repeats is the so called forward–reverse constraint. When the constraint is applied, even when one of the fragments has a perfect match with a repetitive element outside the range, it is not able to be moved to that location to cause miss-assembly.