Review
Adaptation of the human population to the environment: Current knowledge, clues from Czech cytogenetic and “omics” biomonitoring studies and possible mechanisms

https://doi.org/10.1016/j.mrrev.2017.07.002Get rights and content
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Abstract

The human population is continually exposed to numerous harmful environmental stressors, causing negative health effects and/or deregulation of biomarker levels. However, studies reporting no or even positive impacts of some stressors on humans are also sometimes published. The main aim of this review is to provide a comprehensive overview of the last decade of Czech biomonitoring research, concerning the effect of various levels of air pollution (benzo[a]pyrene) and radiation (uranium, X-ray examination and natural radon background), on the differently exposed population groups. Because some results obtained from cytogenetic studies were opposite than hypothesized, we have searched for a meaningful interpretation in genomic/epigenetic studies.

A detailed analysis of our data supported by the studies of others and current epigenetic knowledge, leads to a hypothesis of the versatile mechanism of adaptation to environmental stressors via DNA methylation settings which may even originate in prenatal development, and help to reduce the resulting DNA damage levels. This hypothesis is fully in agreement with unexpected data from our studies (e.g. lower levels of DNA damage in subjects from highly polluted regions than in controls or in subjects exposed repeatedly to a pollutant than in those without previous exposure), and is also supported by differences in DNA methylation patterns in groups from regions with various levels of pollution.

In light of the adaptation hypothesis, the following points may be suggested for future research: (i) the chronic and acute exposure of study subjects should be distinguished; (ii) the exposure history should be mapped including place of residence during the life and prenatal development; (iii) changes of epigenetic markers should be monitored over time.

In summary, investigation of human adaptation to the environment, one of the most important processes of survival, is a new challenge for future research in the field of human biomonitoring that may change our view on the results of biomarker analyses and potential negative health impacts of the environment.

Abbreviations

5mC
5-methyl-cytosine
AHR2
aryl hydrocarbon receptor 2
AS3MT
arsenic (+3 oxidation state) methyltransferase
B[a]P
benzo[a]pyrene
BER
base excision repair
BNC
binucleated cell
c-PAHs
carcinogenic polycyclic aromatic hydrocarbons
CBMN assay
cytokinesis-block micronucleus assay
CEN-MN
micronuclei with the absence of centromere signal
CEN+MN
micronuclei with the presence of centromere signal
Cy-3
cyanine 3
DAPI
4´-6-diamidino-2-phenylindole
FG/100
genomic frequency of translocations/100 cells
FISH
fluorescent in situ hybridization
FITC
fluorescein-5-isothiocyanate
KEGG
Kyoto Encyclopedia of Genes and Genomes
MN
micronuclei
MNNG
N-methyl-N'-nitro-N-nitrosoguanidin
MTase
methyltransferase
NHEJ
non-homologous end-joining
PAR
predictive adaptive response
PCA
principal component analysis
PBL
peripheral blood lymphocytes
PCBs
polychlorinated biphenyls
XRCC SNP
single nucleotide polymorphism X-ray repair complementing defective repair in Chinese hamster cells
WGBS
whole-genome bisulfite sequencing

Keywords

Adaptive response
DNA methylation
Environmental exposure
Micronuclei

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