DNA segmentation through the Bayesian approach.

We present a new approach to DNA segmentation into compositionally homogeneous blocks. The Bayesian estimator, which is applicable for both short and long segments, is used to obtain the measure of homogeneity. An exact optimal segmentation is found via the dynamic programming technique.

Search of periodicities in primary structure of biopolymers: a general Fourier approach.

We discuss a new convenient way to study periodical patterns in primary structures of biopolymers which appeared recently. For the sequence of a biopolymer the symbolic correlation function is constructed, which is used as a digital sequence thus allowing us to perform a Fourier transform. Another fruitful technical improvement is the closing of the sequence in the ring with further scanning of the ring length, which allows the study of periods of the order of the sequence length.

The third nucleotide of the Gly coding triplet remembers the periodicity of the collagen chain.

Collagen is a fibrous protein with a primary structure with complex periodical features. We show using symbolic Fourier transform of the collagen cDNA sequence that basic periodical patterns appear there also. Strikingly they are present in the third position of triplets encoding Gly, which occupies each third position in the sequence of the protein, and to which selection on the protein level does not applied.