Is aging in our genes?
You may get your hair color from your
father’s side of the family and your great
math skills from your mother. These traits
are “in the genes,” so to speak. Likewise,
longevity tends to “run in families”—your
genetic make-up plays an important role
in how you age. You can see evidence of
this genetic connection in families with
siblings who live into their 90s or families
that have generation after generation of
centenarians. These long-lived families are
the basis for many genetic studies.
Identifying the genes associated with any trait
is difficult. First, just locating the gene requires
a detailed understanding of the trait, including
knowledge of most, if not all, of the contributing
factors and pathways related to that trait. Second,
scientists must have clear ways of determining
whether the gene suspected to have a relationship
with the trait has a direct, indirect, or even no effect
on that trait.
BIOLOGY OF AGING: RESEARCH TODAY FOR A HEALTHIER TOMORROW 13
Identifying longevity genes is even more
a gene influences aging in humans, a relation-
complex than determining genes for height or ship, or “association,” may be inferred based hair color, for example. Scientists do not know upon whether a genetic variant is found more all the factors and pathways that contribute
frequently among successful agers, such as
to longevity, and measuring a gene’s effect on
centenarians, compared with groups of people
long-lived animals, including humans, would
who have an average or short lifespan and
literally take a lifetime! Instead, scientists
health span.
have identified hundreds of genes that affect
Several approaches are used to identify
longevity in short-lived animal models, like
possible genes associated with longevity in
worms and flies. Not all of these genes pro-
humans. In the candidate gene approach,
mote long life. Sometimes mutating or elimi-
scientists look for genes in humans that serve
nating a gene increases lifespan, suggesting
similar functions in the body as genes already
that the normal function of the gene limits
associated with aging in animal models, so-
longevity. Findings in animal models point to called “homologs” or “orthologs” to animal places for scientists to look for the genes that
genes. For instance, after finding longevity
may influence longevity in humans.
genes involved in the insulin/IGF-1 pathway
of animal models, researchers look for the