Nucleotide repeats in mitochondrial genome determine human lifespan

Direct nucleotide repeats can facilitate deletions of segments of mitochondrial genome1, leading to a wide range of neuromuscular disorders1,2 as well as aging2,3 in humans. We hypothesized that the number of the direct perfect repeats in human mitochondrial genomes influences longevity through the formation of harmful mtDNA deletions in the somatic cells. The analysis of the complete mitochondrial genomes of 762 unrelated Japanese individuals4-6 reveals a negative correlation between the abundance of the direct perfect repeats and the expected longevity. This association is largely due to the disruption of the common repeat (8470,13447) by a point mutation 8473C which occurred at the origin of the D4a haplogroup characterized by extreme longevity in Japan7. Our results provide the first evidence for correlation between the number of nucleotide repeats and the lifespan on intraspecific level

Structural and Dynamic Stability of Model Predator-Prey Systems

A modified set of Volterra's differential equations for dynamics of prey and predator populations is analyzed. This modification takes three effects into consideration: (1) Satiation of predator resulting in the inability of either predation rate or predator reproduction rate to increase infinitely with growth of prey numbers; (2) Limited resources of prey, as a result of which prey populations cannot increase infinitely even in the absence of predators; 3) Limited external resources (unrelated to prey) of predators, as a result of which predator populations cannot grow infinitely even when there is an excess of prey. Analysis of this set of equations gives many different behavioral regimes depending on the values of parameters. This model as a whole can be used to demonstrate a number of situations: situations in which the behavior of a predator-prey system is adequately described by Volterra's equations; situations in which these equations cannot describe the dynamics of prey-predator interactions; situations in which the system behaves similarly to Volterra's under certain initial conditions but not under other conditions

Model of Eutrophication in Predator-Prey Systems

In this paper a model of a simple food-prey-predator system existing in a flow is built. The model predicts the emergence of sharp predator-prey oscillations when the initial food concentration is very high or the flow rate is very slow. The behavior of the model is compared with the effect of antropogenic eutrophication

Rate of promoter class turn-over in yeast evolution

BACKGROUND: Phylogenetic conservation at the DNA level is routinely used as evidence of molecular function, under the assumption that locations and sequences of functional DNA segments remain invariant in evolution. In particular, short DNA segments participating in initiation and regulation of transcription are often conserved between related species. However, transcription of a gene can evolve, and this evolution may involve changes of even such conservative DNA segments. Genes of yeast Saccharomyces have promoters of two classes, class 1 (TATA-containing) and class 2 (non-TATA-containing). RESULTS: Comparison of upstream non-coding regions of orthologous genes from the five species of Saccharomyces sensu stricto group shows that among 212 genes which very likely have class 1 promoters in S. cerevisiae, 17 probably have class 2 promoters in one or more other species. Conversely, among 322 genes which very likely have class 2 promoters in S. cerevisiae, 44 probably have class 1 promoters in one or more other species. Also, for at least 2 genes from the set of 212 S. cerevisiae genes with class 1 promoters, the locations of the TATA consensus sequences are substantially different between the species. CONCLUSION: Our results indicate that, in the course of yeast evolution, a promoter switches its class with the probability at least ~0.1 per time required for the accumulation of one nucleotide substitution at a non-coding site. Thus, key sequences involved in initiation of transcription evolve with substantial rates in yeast

Инновационный подход к управлению педагогическим коллективом в детском саду

Table S5. Mean proportions of LoF alleles among all, core and hard-core genes for each species. (XLSX 12 kb

Extensive parallelism in protein evolution

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On the birth of limit cycles for non-smooth dynamical systems

The main objective of this work is to develop, via Brower degree theory and regularization theory, a variation of the classical averaging method for detecting limit cycles of certain piecewise continuous dynamical systems. In fact, overall results are presented to ensure the existence of limit cycles of such systems. These results may represent new insights in averaging, in particular its relation with non smooth dynamical systems theory. An application is presented in careful detail