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3.
J Biomol Struct Dyn ; 18(1): 103-12, 2000 Aug.
Article in English | MEDLINE | ID: mdl-11021655

ABSTRACT

Previously, when discussing the properties of one parameter discrete model of genetic diversity (M.Yu. Shchelkanov et al, J. Biomol. Struct. Dyn. 15, 887-894 (1998)), we took into account Hamming distance distribution only between precursor and arbitrary descendant sequences. However, really there are sets of sequence populations produced during amplification process. In the presented work we have investigated Hamming distance distributions between sequences from different descendant sets produced in the frame of one parameter discrete model. Two basic descendant generation operators (so called amplifiers) are introduced: 1) the last generation amplifier, L, which produces descendants with precursor elimination; 2) all generations amplifier, G, which produces descendants without precursor elimination. Generalization of one-parameter discrete model for the case when precursor sequences do not coincide are carried out. Using this generalization we investigate the distribution of Hamming distances between L- and G-generated sequences. Basic properties of L and G operators, L/G-choice alternative problem have been discussed. Obtained results have common theoretical significance, but they are more suitable for high level genetic diversity process (for example, HIV diversity).


Subject(s)
Genetic Variation , Models, Genetic , Mathematics
4.
J Biomol Struct Dyn ; 17(3): 597-605, 1999 Dec.
Article in English | MEDLINE | ID: mdl-10636093

ABSTRACT

Stochastic properties of previously introduced one parameter discrete model of genetic diversity (M. Yu. Shchelkanov et al, J. Biomol. Struct. Dyn. 15, 887-894 (1998)) are investigated. Two approaches are compared: (A) when the on-step substitution number and/or the number of substitution steps are random variables; (B) referred parameters are replaced by mathematical expectations of the respective variables. It has been demonstrated, that estimations of sequence measure based on the number of replication steps are more under the assumption of case (A) as compared with (B). Thus, real biological situation relating to the case (A) could additionally promote the increasing of distinctions between different taxons (e.g. HIV, etc.). Peculiarities of one-parameter discrete model of genetic diversity during calculation of the distinctions between symbol (e.g. nucleotide) sequence sets are also discussed.


Subject(s)
Genetic Variation , Models, Genetic , Stochastic Processes , HIV/genetics , Mathematics , Proteins/chemistry , RNA/chemistry , RNA/genetics , RNA Viruses/genetics , RNA, Viral/chemistry , RNA, Viral/genetics , Random Allocation
5.
J Biomol Struct Dyn ; 15(5): 877-85, 1998 Apr.
Article in English | MEDLINE | ID: mdl-9619510

ABSTRACT

Distribution functions for intra- and inter- HIV-1 V3-loop subtypes amino acid Hamming distances were calculated (850 V3-loop sequences from the Los Alamos HIV-1 Database (1996) were used). These functions have pronounced bell-like shape. Such shapes of the histograms for HIV-1 V3 intra- and inter-subtype distriutions are discussed to confirm the applicability of different hierarchical cluster procedures for HIV-1 V3 classification. Two-mode distribution for the subtype E could sertificate that this subtype includes two thinner taxons.


Subject(s)
HIV Envelope Protein gp120/chemistry , Mathematical Computing , Peptide Fragments/chemistry , Amino Acids , Humans
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