PubMed Health⌕ Search

Biomedical subjects

A B Korol'

Publications and source records attributed to A B Korol'.

10 recordsLinked to original sources
PubMed1990

[Efficiency of feedback selection for recombination in Drosophila].

A number of theoretical models have been developed in population genetics to explain the evolution of recombination system under natural selection for adaptive traits. Using Drosophila cage populations of large size the effect of selection for resistance to daily temperature fluctuations on the rec-system was studied in this work. It is established that selection for population adaptability to extreme conditions leads during several tens of generations to significant increase in crossing-over rate within various parts of the genome (especially in b-cn and ru-h of chromosomes 2 and 3), as well as to relaxation of exchange interference for adjacent and non-adjacent segments. The Fisher's theoretical prognosis about tightening of linkage in optimal constant conditions was experimentally confirmed for the first time.

Adaptation, Physiological↗
PubMed1990

[Evolution of recombination in "host-parasite" systems. Multilocus models].

Evolution of the recombination system caused by antagonistic species interactions (host and parasite, for example) was studied. The genetic structure of host population as well as that of parasite is explicitly present in our models. The selection intensity depends on host's resistance and parasite's virulence, both controlled by polygenic systems. The rec-system dynamics was numerically studied using the genetic operators method. It is shown that high-recombination alleles of the rec-modificator can have a short-term selective advantage in both interacting populations simultaneously.

Animals↗
PubMed1989

[Increased recombination in a multi-locus system during environmental fluctuations].

The role of variability of environment as a factor of recombination evolution is studied. It was shown that selection in multilocus system under cyclic or random fluctuations of external conditions results in rapid increase in recombination frequency, even under free recombination between the rec-modificator and the selected system (SS). If so, pair-vise linkage disequilibrium coefficients have unchanged signs and are negative, and the advantage of rec+ alleles is provided by changes in signs of disequilibriums of higher order. The low frequency environmental fluctuations maintain recombination as it is, while high frequency ones induce the substitution of the low level by high. It was established that the recombination promoting mechanism of crossing-over maintenance, due to elimination of non-optimal allelic combinations of SS loci under temporal optimum variations, may be accomplished by smaller genetic load, than under elimination of deleterious mutations.

Environment↗
PubMed1988

[Host-parasite interaction as a factor in the evolution of genetic recombination].

A model of the rec-system evolution determined by species interactions of the host-parasite type has been studied. In contrast to known formalizations, the genetic structure of both populations is clearly represented in our model, which makes it possible to set the mode of their interrelations in a more natural and biologically consistent way. The numerical analysis has revealed the situations, where nondecreasing oscillations of the linkage disequilibrium coefficient and, consequently, the selection favourable for higher recombination occur in a system. The evolutionary advantage of recombination has been demonstrated both in terms of population mean fitness and in the models with locus modifier of recombination.

Animals↗
PubMed1987

[Linkage between quantitative and marker loci. V. Joint analysis of various marker and quantitative traits].

New versions are suggested to analyse marker and quantitative characters combinations. Possible modes of application of the algorithms developed for recombination analysis are discussed, including: 1) the estimation of crossing-over frequency between markers with incomplete penetrance, 2) the quantitative character variability account to analyse genetic interference, 3) search for genetic factors affecting a set of quantitative characters, 4) the evaluation of differences between male and female meiosis at the crossingover level etc.

Algorithms↗
PubMed1986

[Evolution of the dominance of rec-loci. A mathematical model].

The possibility of evolutionary explanation of dominance relations for alleles in selective-neutral rec-loci was explored by means of numerical experiments. It was shown that selection for two-loci fitness system causing the secondary (induced) selection for the rec-system, results in changing the allele frequency of the second-level modificator gene controlling the dominance relations in the rec-locus. The dominance of rec-allele, providing the favourable for the given conditions level of crossing-over between selected fitness loci, is established, due to these changes. It was found that the neutral dominance modificator can influence the dynamics of the whole system.

Animals↗