Genetic background may affect adaptions to aging

Date:
August 19, 2020
Source:
University of California - Riverside
Summary:
How we adapt to aging late in life may be genetically influenced,
according to a study led by a psychologist. The research has
implications for how epigenetic factors relate to aging.



FULL STORY ==========================================================================
How we adapt to aging late in life may be genetically influenced,
according to a study led by a psychologist at the University of
California, Riverside.


==========================================================================
The research, published in Aging Cell, has implications for how epigenetic factors relate to aging. Epigenesis is a process in which chemicals
attached to DNA control its activity. Epigenetic changes, which can be
passed on to offspring, may be critical to accelerated aging as well
as declines in cognitive and physical functioning that often accompany
aging. Epigenetic modifications resulting in altered gene expression
may occur due to a number of biological processes, including one the researchers focused on: DNA methylation.

In DNA methylation, methyl groups are added to the DNA molecule. DNA has
four different types of nucleotides: A, T, G, and C. DNA methylation
occurs at the C bases of eukaryotic DNA. Changes in DNA methylation
correlate strongly with aging.

Chandra Reynolds, a professor of psychology at UCR and her colleagues considered DNA methylation across a 10-year span in 96 pairs of same-sex
aging Swedish and Danish twins -- the first longitudinal twin study
to establish the extent to which genetic and environmental influences contribute to site- specific DNA methylation across time.

They found individual differences in blood DNA methylation measured at
more than 350,000 sites in the aging twins across the epigenome are partly heritable in late life and longitudinally across a decade -- ages 69 to
79. These findings can help scientists better understand the genetic and environmental contributions to the stability and dynamics of methylation
in aging and sets a stage for future work in diverse populations.

"We also found methylation sites previously associated with age and
included in methylation 'clocks' are more heritable than the other
remaining sites," said Reynolds, an expert on cognitive aging, who led
the research. "The sites evidencing the greatest heritability reside in
genes that participate in immune-inflammatory as well as neurotransmitter pathways. Sites that show less stability in methylation across 10 years
reside in genes that participate in stress-related pathways." The finding
that age-related sites are among the most heritable supports the genetic regulation of biological aging rates, including regulation of how well
people respond to environmental challenges, such as exposures to viruses
like SARS-Cov-2, the virus that spreads COVID-19.

"Altered methylation patterns have been observed with aging, and
as methylation differences may result in part from our experiences
and behavior, they may be modifiable," Reynolds said. "Our results
highlight that even in late life, amid the 'slings and arrows of
outrageous fortune,' some of the individual differences in methylation
are moderately heritable and contribute to methylation patterns 10 years later." Reynolds further explained that genetic influences contribute
to stability while nonshared factors accumulate in importance with age, signaling an increasing diversity of how people respond to environmental exposures.

Heritability is due generally to stable genetic contributions, she said,
but with an increasing role of nonshared environmental factors -- those
unique to a person and not shared with her siblings -- across age.

According to Reynolds, DNA methylation sites related to aging are more heritable overall. This is consistent with the genetic regulation of
biological aging rates, perhaps including sites in genes involved in immune-inflammatory pathways and neurotransmitter pathways, and explains
how people adapt to health and aging conditions.

"The most heritable sites may participate in these pathways, which
suggests that adaptions to aging and senescence may be differentially
impacted by genetic background," she said. "That the most heritable or
familial sites lie within genes that participate in immune-inflammatory pathways suggests that how we adapt to aging processes, including
resistance to -- or challenges from - - illness, may be partly genetically regulated."

========================================================================== Story Source: Materials provided by
University_of_California_-_Riverside. Original written by Iqbal
Pittalwala. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Chandra A. Reynolds, Qihua Tan, Elizabeth Munoz, Juulia Jylha"va",
Jacob
Hjelmborg, Lene Christiansen, Sara Ha"gg, Nancy L. Pedersen. A
decade of epigenetic change in aging twins: Genetic and
environmental contributions to longitudinal DNA methylation. Aging
Cell, 2020; DOI: 10.1111/ acel.13197 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200819170219.htm

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