Profile Comparison
In 1987 Michael Gribskov, Andrew McLachlan and David Eisenberg introduced the method of profile comparison for identifying distant similarities between proteins. Rather than using a single sequence, profile methods use a multiple sequence alignment to encode a profile which contains information about the conservation level of each residue. These profiles can then be used to search collections of sequences to find sequences that are related. Profiles are also known as Position Specific Scoring Matrices (PSSMs). In 1993 a probabilistic interpretation of profiles was introduced by David Haussler and colleagues using hidden Markov models. These models have become known as profile-HMMs.
In recent years methods have been developed that allow the comparison of profiles directly to each other. These are known as profile-profile comparison methods.
Read more about this topic: Sequence Analysis
Famous quotes containing the words profile and/or comparison:
“Expecting rain, the profile of a day
Wears its soul like a hat....”
—John Ashbery (b. 1927)
“The difference between human vision and the image perceived by the faceted eye of an insect may be compared with the difference between a half-tone block made with the very finest screen and the corresponding picture as represented by the very coarse screening used in common newspaper pictorial reproduction. The same comparison holds good between the way Gogol saw things and the way average readers and average writers see things.”
—Vladimir Nabokov (1899–1977)