Strings 2008 2 5

Similarity of sequences

In bioinformatic reality finding exact matches between sequences is not enough. Biological sequences may not be perfectly identical because of

1. experimental errors that may have occurred in the determination of the sequence,
2. mutations. Sequences may have changed in course of evolution

Further, biologist more often want to find other sequences that are similar to their sequence of interest rather then to re-identify identical sequences.

In the next sections we will explore how to compare and search for similar sequences.

How can sequences change (class room brain storming)

Discovery question: Imagine you have to type The quick brown fox jumps over the lazy dog 500 times on a type writer. What sort of changes in the text between the 500 versions are you likely to observe? Compare these changes with the changes you would expect comparing DNA sequences.

goto How can biological sequences change

--ThomasHuber 14:29, 10 January 2008 (EST)