82. Given below are two statements one is labelled as Assertion A and the other is labelled as
Reason R:
Assertion A: The dot matrix method of sequence alignment is a very basic method that should be
used first, before other more complex methods.
Reason R: The diagonal Dot Matrix Display can readily reveal presence of insertions/deletions and
direct and inverted repeats that are more difficult to find by the other, more automated methods.
In the light of the above statements, choose the most appropriate answer from the options given
below:
A. Both A and R are correct and R is the correct explanation of A
B. Both A and R are correct but R is not the correct explanation of A
C. A is correct but R is not correct
D. A is not correct but R is correct

Detailed Explanation:

The dot matrix method is one of the earliest and simplest techniques used for sequence alignment. It provides a visual representation of sequence similarity through a grid where each axis represents one of the sequences. When characters match, a dot is placed in the grid, forming lines or patterns that help in visualizing alignments, insertions, deletions, and repeats.

Assertion A:

“The dot matrix method of sequence alignment is a very basic method that should be used first, before other more complex methods.”

This statement is not entirely correct. While the dot matrix method is basic and provides an intuitive visual understanding, it is not a mandatory first step in sequence alignment workflows. In practical applications, more precise and automated methods like dynamic programming (Needleman-Wunsch or Smith-Waterman) or heuristic methods (BLAST) are often used directly, especially for large datasets.

Reason R:

“The diagonal Dot Matrix Display can readily reveal presence of insertions/deletions and direct and inverted repeats that are more difficult to find by the other, more automated methods.”

This statement is correct. The dot matrix can indeed reveal structural features of sequences, such as direct repeats (shown as parallel diagonals) and inverted repeats (shown as mirrored diagonals), as well as insertions or deletions (gaps in diagonals). Such visualization is useful, particularly for analyzing non-coding regions or genomic structural variations.

Correct Answer: D

A is not correct but R is correct