Shamanskiy, V. A. | bioRxiv Science

bioRxiv2024

Harnessing Stress: balancing the Burden of Slightly-Deleterious Variants by a Handicap

Numerous empirical studies have revealed epistatic interactions among deleterious variants. In this paper, we assume such interactions are widespread and analyze the resulting shift in mutational burden and average population fitness following the introduction of a strong and universal stress (hereafter "handicap"). We demonstrate that organisms with a low burden of slightly-deleterious variants (SDVs) are more likely to survive exposure to a handicap, whether genetic or environmental, leading to a purifying effect on the population. We further discuss the potential applications of harnessing such interactions for evolutionary and population studies as well as for population management.

genetics↗

bioRxiv2021

Mitochondrial mutational spectrum is associated with mammalian longevity: a novel signature of oxidative damage.

The mutational spectrum of the mitochondrial DNA (mtDNA) does not resemble any of the known mutational signatures of the nuclear genome and variation in mtDNA mutational spectra between different organisms is still incomprehensible. Since mitochondria is tightly involved in aerobic energy production, it is expected that mtDNA mutational spectra is affected by the oxidative damage. Assuming that oxidative damage increases with age, we analyze mtDNA mutagenesis of different species. Analysing (i) dozens thousands of somatic mtDNA mutations in samples of different age (ii) 70053 polymorphic synonymous mtDNA substitutions, reconstructed in 424 mammalian species with different generation length and (iii) synonymous nucleotide content of 650 complete mitochondrial genomes of mammalian species we observed that the frequency of AH>GH substitutions (H - heavy chain notation) is twice higher in species with high versus low generation length making their mtDNA more AH poor and GH rich. Considering that AH>GH substitutions are also sensitive to the time spent single stranded (TSSS) during asynchroniuos mtDNA replication we demonstrated that AH>GH substitution rate is a function of both species-specific generation length and position specific TSSS. We propose that AH>GH is a mitochondria-specific signature of oxidative damage associated with both aging and TSSS.

bioinformatics↗