Terms used in molecular evolution
Here follows the explanation of some frequently used terms and
some frequent errors in molecular evolution
- Indel: position in a sequence alignment where one of the
sequences has acquired an insertion or extension or has undergone
a deletion.
- Identity: percentage of identical residues in pairwise aligned
sequences. Normally deletions or insertions are not taken into
consideration, since it is not possible to tell how many events
have been at the basis of the creation of such an indel.
- Homology: two sequences are homologous or have homology when
they have evolved from a common ancestral sequence. The same holds
for the aligned residues in a sequence alignment. Homologous
residues are derived from a common ancestral residue.
NB: The terms similarity and homology as percentage should not
be used. Two sequences can be similar, and have a certain percentage
of identity, but cannot have a certain percentage of similarity. The
same holds for homology.
Last updated: 8 August 1997.
created by :Fred
Opperdoes