[Biojava-l] Emission with duration

Schreiber, Mark mark.schreiber@agresearch.co.nz
Thu, 31 Oct 2002 11:11:39 +1300


Hi -

How difficult would it be to make a markov model that emitted sequence
from a state using a duration distribution. For Example in gene finding
programs the model often loops over the coding state, unfortunately this
means the probability of a certain length of sequence declines
geometrically. In reality the length distribution of genes is a gamma
distribution.

Without looking into the internals, I think you could sample the
duration distribution to tell you how many times to sample the coding
(or other) state. When doing the forward backward viterbi stuff I guess
it would have to score the seqeunce by emission and rather than
factoring in the transition probabilities it would look up the duration
distribution instead.

Now that we have the Integer sub alphabets this may not be too hard (I
hope).

- Mark

Mark Schreiber PhD
Bioinformatics
AgResearch Invermay
PO Box 50034
Mosgiel
New Zealand
 
PH:   +64 3 489 9175
FAX:  +64 3 489 3739

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