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# Changes

From Genome Analysis Wiki

→Acyclicity

== Acyclicity ==

Motifs are required to be acyclic. For example, a motif ACACAC should just be represented by AC as it is 3 copies of AC.

A sequence is cyclic if and only if there exists a sub sequence in which it is a multiple copy of.

The definition can be more explicit as follows:

A sequence is cyclic if and only if there exists a non trivial shift of the sequence that is equivalent to the sequence.

Take for example, the sequence ACACA, is this a bona fide motif? After it seems like it is 2.5 copies of AC and AC might be

more appropriate.

shift 0: ACACA

shift 1: CACAA

shift 2: ACAAC

shift 3: CAACA

shift 4: AACAC

So ACACA is a bona fide motif.

== Fractional counts ==