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).
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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 ?
Jalavisto (1951) – 12,876 Scandinavians (1500-1829) 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%) heritability does not change with time
Population Studies 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
Twin studies 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
Twins 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 short life Biomarkers a better measure of age related changes ? Genetic vs. Environmental Control
Gender Differences Stronger Sex ??
Gender Gap Differential Mortality: Changes Sex Ratio At conception 170:100 (est.) End 1st Trimester 130:100 At Birth 106:100 Adolescence 100:100 Age 75 60:100 Why ? Genetics ? Biology ? Behavior ? Environment ?
Gender Gap Y-Chromosome- 78 genes, all but 18 directly involved with spermatogenesis (sperm production) Single Y Chromosome- no chance for genetic recombination “Proband” males (partial deletion of Y chromosome) 82.4 years vs. 77.4 for females (in same family)
Gender Gap 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
Gender Gap 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 female infanticide Other animal species - males live longer in some