Genetics and Longevity. Human Studies. Genealogical Studies. Bell - 1918 Descendents of William Hyde (died 1681) n = 8,798 correlation between parental longevity and offspring longevity greater influence of father ?. Yuan - 1932 Chinese family 1365-1849 (n = 7,500).
Bell - 1918
Descendents of William Hyde (died 1681)
n = 8,798
correlation between parental longevity and
greater influence of father ?
maternal longevity better predictor
Mayer (1991) - New England 1578-1963
n = 14,549, 6 families
what portion of longevity is genetically inherited ?
Does this value change over time ?
95% confidence limits 0.10 -0.33 (10-33%)
does not change with time
Actuarial Studies -
parental age has affect on length of life of offspring
father longevity better predictor
details of ind. Studies vary slightly, but overall trend is clear
Not all familial effects are genetic
twin studies can sort this out
Kallman 1957 -
1739 pairs of twins
at least one twin > 60
effects of parental life span as well as
similarity between twins
fraternal vs. identical
Correlation between parental span and offspring
Avg. difference between fraternal twins = 6 years
for same sex twins, 9 years for diff. Sex
Identical Twins - 3 year diff.
Heritability - 0.33 to 0.5
Heredity is an important factor determining life span
What we inherit is the absence of a tendency for a
Biomarkers a better measure of age related changes ?
Genetic vs. Environmental Control
Stronger Sex ??
Differential Mortality: Changes Sex Ratio
At conception 170:100 (est.)
End 1st Trimester 130:100
At Birth 106:100
Age 75 60:100
Genetics ? Biology ? Behavior ? Environment ?
78 genes, all but 18 directly involved with
spermatogenesis (sperm production)
Single Y Chromosome-
no chance for
“Proband” males (partial deletion
of Y chromosome)
82.4 years vs. 77.4 for females
(in same family)
Role of androgens ? (testosterone)
eunuchs (postpubertal castration)
live longer than controls
Physiology vs. Behavior ??
Testosterone given to female mice
lowers their immune response
Protective effects of estrogen in coronary artery disease
Waldron 1987 - 18 % of gap due to hormone diff.
55% due destructive behaviors
Smoking, guns, cars, alcohol
In U.S. Gender Gap has doubled since 1900
(argues against biological/genetic explanation)
Other ethnic/ cultural / societal groups
Gap varies (10 years to -2.8)
Males live longer in 6/157 populations
general high rate of premature death
mortality of childbirth
Other animal species - males live longer in some