Predicting quality using percentage identity
Percentage identity is a frequently quoted statistic for an alignment of
two sequences. However, the expected value of percentage identity is strongly
dependent upon the length of alignment and this is frequently overlooked.
Figure 4 shows the percentage
identities found for a large number of locally optimal alignments of differing
length between proteins known to be of unrelated three dimensional structure.
Clearly, an alignment of length 200 showing 30%identity is more significant
than an alignment of length 50 with the same identity.
Figure 4.
Original from:
geoff.barton@ox.ac.uk
This page original location is at http://barton.ebi.ac.uk/papers/rev93_1/subsubsection3_5_1_1.html#SECTION0005110000000000000