[Sequences resembling fragments of mitochondrial DNA in the human genome: features of evolution]. / Posledovatel'nosti, podobnye fragmentam mitokhondrial'noi DNK, v genome cheloveka: osobennosti évoliutsii.

Mitochondrial-like sequences and their homologues from primate mitochondria are investigated to define direction and rate of evolution, time of integration into nuclear genome. The analysis showed that mito-like sequences differ from mitochondrial homologues by high level of symmetria of two chains of DNA. Besides that, difference between mito-like and Homo sapiens sequences in their GC-contents is found. Apparently there is GC-pressure of nuclear genome region, being the place of integration of mito-like sequence, that brings about equalization of GC-contents in nuclear region and mito-like sequences. Properties of descent mitochondrial sequence play important role in the difference of mito-like and Homo sapiens sequences also.

Statistical analysis of L-tuple frequencies in eubacteria and organelles.

This work is an attempt to study the structural features and evolutionary patterns of nucleotide sequences by analyzing their 1- through 4-plet frequencies and statistical relations between them. We present mathematical apparatus for this analysis. In particular, we introduce criteria to estimate the degree of homogeneity of L-plet composition in a given set of sequences and the dependence of the L-plet frequencies on the composition of lower orders. We apply these criteria to the study of eubacteria, mitochondria and chloroplasts. We demonstrate that L-plet frequencies are quite useful for revealing evolutionary relationship between DNA sequences and that the non-random distribution is more typical for doublets than to triplets. Non-randomness of triplet composition is more characteristic to coding than to non-coding regions, while no significant differences in dinucleotide composition can be observed. The obtained results can be used for revealing possible mechanisms of the codon usage phenomena.

VOSTORG: a package of microcomputer programs for sequence analysis and construction of phylogenetic trees.

VOSTORG is a new, versatile package of programs for the inference and presentation of phylogenetic trees, as well as an efficient tool for nucleotide (nt) and amino acid (aa) sequence analysis (sequence input, verification, alignment, construction of consensus, etc.). On appropriately equipped systems, these data can be displayed on a video monitor or printed as required. They are implemented on IBM PC/XT/AT/PS-2 or compatible computers and hardware graphic support is recommended. The package is designed to be easily handled by occasional computer users and yet it is powerful enough for experienced professionals.