Answer Happy

1. Questions 1-3 will test your understanding of the feasibility conditions of global pairwise sequence alignment (that is, what makes an alignment). Let X = AC and Y = CA be two DNA sequences. Which of the following are global alignments of X and Y? X' = AC and Y' = CA. X'= AC -- and Y' = -- CA. X' = AC and Y' = - - CA. X' = CA and Y' = CA. X'= CA- and Y' = -AC. 2. How many possible global alignments are there for two sequences X and Y if | X = Y = 1? How many possible global alignments are there for two sequences X and Y if | X| = |Y| = 2? Give your answer below as two numbers separated by a space (e.g., 17 100) ANS 3. Recall from the feasibility conditions of a sequence alignment that for X' and Y' to be an alignment of two sequences X and Y, X' and Y' must satisfy this condition (among other conditions): There does not exist an i such that X = Y{ = –. What happens if we remove this condition; that is, allow X = Y = - for some values of ?? The number of possible alignments of a pair of sequences becomes smaller (as compared to the number of alignments that satisfy the condition). The number of possible alignments of a pair of sequences increases exponentially in the lengths of X and Y (as compared to the number of alignments that satisfy the condition). The number of possible alignments of a pair of sequences becomes infinite. The number of possible alignments of a pair of sequences does not change (as compared to the number of alignments that satisfy the condition). The number of possible alignments of a pair of sequences doubles (as compared to the number of alignments that satisfy the condition).