Download The antagonistic pleiotropy model

Chap.16 Aging and
Disease
鄭先祐 (Ayo) 教授
國立台南大學 環境與生態學院
生態科學與技術學系
環境生態研究所 + 生態旅遊研究所
Aging and disease
Senescence in the wild?
Theoretical and empirical
perspectives on senescence
 The antagonistic pleiotropy model
 Disposable soma theory and longevity
Hormones, heat-shock proteins,
and aging
 Glucocorticoids, stress, and aging
 Heat-shock proteins and aging
Disease and animal behavior
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Bill is shown here at
four different ages: 20,
21, 50, and 51.
It the probability of
Bill’s surviving from
age 20 to 21 I greater
than the
corresponding
probability of
surviving from age 50
to 51, then
senescence is
occurring.
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Senescence in red deer populations
Fig. 16.2
After a female reaches about eight
years old, senescence is seen in the
lowered birthrate of the calves she
produces.
Senescence was greater in females that
had reproduced often when they were
young (green points) compared to
females that had produced fewer calves
when young (orange points).
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Senescence in the wild?
Natural historians and ethologists
long believed that senescence was
rate in nature, since the prevailing
wisdom was that animals rarely live
long enough to begin senescing.
It was not until Daniel Promislow
undertook a rigid and systematic
approach that ethologists realized
that senescence occurred in
animals in the wild.
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In a sample of 26 species
of mammals, most do not
show signs of
senescence until after the
age of maturity. Both the
x-axis and the y-axis are
measured on a log scale.
The solid line represents
the points at which age of
maturity and senescence
occur at the same time.
Points above the line
indicate species that
senesce after maturity.
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Theoretical and empirical
perspectives on senescence
 The antagonistic pleiotropy model
 A gene is pleiotropic when it has more than one
effect on an organism
 Antagonistic pleiotropy refers to instances in which
the multiple effects of a single gene have opposite
(antagonistic) effects on fitness.
 Disposable soma theory and longevity
 Human longevity
 Tsetse flies
 Cross-species tests
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The antagonistic pleiotropy model
案例：
The abnormal abdomen gene in fruit
flies may be just such a pleiotropic gene.
The effect of the abnormal abdomen
gene is to cause the juvenile cuticle of
the fruit fly to remain in place into
adulthood.
 It greatly increase early reproduction in
the fruit fly, but it also speeds up
senescence and decreases longevity.
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Disposable soma theory
 Human longevity
 Demographic information from a
historical population of 16,500 families
that inhabited the Krummhorn region of
Germany between 1720-1870.
 They focused on two fundamental
predictions of the disposable soma
theory
1. That marred women should have shorter life
spans than their unmarried counterparts
2. There should be a negative relationship between
fecundity and life span.
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問題與討論
Ayo NUTN website:
http://myweb.nutn.edu.tw/~hycheng/