Download - *:Shostak, S., Albany: SUNY Press; 2002
*:Shostak, S., Albany: SUNY Press; 2002.
*
Shostak, S., 2004.
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
2) The chronic disease modelThe accordion: uniform expansionThe bagpipe: expansion at one stage
Changes in lifespan and fecundity are due to changes in the allocation of stem-cells.
Is there a biological explanation?
3) Hypotheses for testing and a mechanism for theorizing
Neoteny
simulating change
1) The already known
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens?
Increasing lifespan
the absolute life span limit, maximum life-span potential, a practical life span limit, an age at which the force of mortality is close to unity, an age up to which a certain proportion of the population survives, or a theoretically maximal age
No matter how you measure it:
or where you look for it!
Foster, George M., Old age in Tzintzuntzan, Mexico, pp. 115–137. inAging: Biology and Behavior, James L. McGaugh and Sara B. Kiesler, eds., New York: Academic Press; 1981.
Tzintzuntzan Deaths: 1940–1949 and 1969–1978
years
0
5
10
15
20
25
40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78
total deaths
tota
l death
s
years
Tzintzuntzan population: 1940–1949 and 1969–1978
0
500
1000
1500
2000
2500
3000
40 42 44 46 48 50 52 54 56 58 60 62 64 66 68 70 72 74 76 78
total population size
popu
lati
on
no data available
pg.
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
Intrinsic fertility rates: rates that would eventually prevail if population were to experience the age-specific birth rates for a given year over a long period of time.Data from Table 1-6, pg. 7. National Center for Health Statistics. Vital Statistics of the United States, 1993, Vol 1, Natality. Hyattsville, Maryland. 1999.
year
0
5
10
15
20
25
30
60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92
Intrinsic fertility rates for all races in US. From Table 1–6, pg. 7 National Center for Health Statistics, 1993
bir
th r
ate
s p
er
10
00
pop
ula
tion
0.00
50.00
100.00
150.00
200.00
250.00
300.00
60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92
15–19
20–24
25–29
30-34
35–39
40–44
45–49
5-year age groups ofmothers
Live b
irth
s p
er
1,0
00 w
om
en
in s
peci
fied
gro
ups Birth Rates by Age of Mother in U.S. from 1960 to 1993
yearsNational Center for Health Statistics. Vital Statistics of the United States, 1993, vol 1, natality. Hyattsville, Maryland. 1999.
Pregnancy Rates by Age of Mother in U.S. from
1980 to 1999Revised for consistency
with 2000 census.
donors born in the 1950s 1970s P
Median sperm concentration 98 78 (X one million / ml)10th to 90th centile 38.6–218.4 21.0–166.4 0.002
Total number 169.7 129sperm (X one million)10th to 90th centile 52.3–503.9 29–325.8 0.0065
Semen quality of birth cohorts
Irvine, S., et al., Evidence of deteriorating semen quality in the United Kingdom. BMJ, 312:467–71; 1996.
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
2) The chronic disease model
Is there a biological explanation?
embryo
neonate
juvenile
adolescent
young adultold adult
senescent
age
stage
fetus
death
Vjuvenile(x)
embryo
fetus
neonate
juvenile
adolescent
young adult
old adult
senescent
death
Vembryo(x)
Vfetus(x)
Vneonate(x)
Vadolescent(x)
Vyoung adult(x)
Vold adult(x)
embryo(x)
senescent(x)
old adult(x)
young adult(x)
adolescent(x)
juvenile(x)
neonate(x)
fetus(x)
Stages
Static Model: t2Stage N
Pre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death100 0 0 0 0 0 0 0 0 0
ToPre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
From Pre-embryo 0 0.8 0 0 0 0 0 0 0 0.2Embryo 0 0 0.9 0 0 0 0 0 0 0.1Fetus 0 0 0 0.98 0 0 0 0 0 0.02Neonate 0 0 0 0 0.99 0 0 0 0 0.01Juvenile 0 0 0 0 0 0.99 0 0 0 0.01Adolescent 0 0 0 0 0 0 0.92 0 0 0.08Young Adult 0 0 0 0 0 0 0 0.55 0 0.45Old Adult 0 0 0 0 0 0 0 0 0.04 0.96Senescent 0 0 0 0 0 0 0 0 0.08 0.92Death 0 0 0 0 0 0 0 0 0 1
Stage n+1Pre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
0 80 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 80 0 0 0 0 0 0 0 20
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
2) The chronic disease modelThe accordionuniform expansion
expansion at one stageThe bagpipe
simulating changeThe chronic disease model
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
2) The chronic disease modelThe accordionuniform expansion
Each stage of a lifetime expands and contracts.
simulating change
embryo
fetus
neonate
juvenile
adolescent
young adultold adult
senescent
age
stage
expandedembryo
expandedfetus
expandedneonate
expandedjuvenile
expandedadolescent
expanded
young adult expanded
senescence
expanded
old adult
deathdeathdeathdeathdeath
AccordionStage N Pre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
100 0 0 0 0 0 0 0 0 0
ToPre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
From Pre-embryo 0.4 0.4 0 0 0 0 0 0 0 0.2Embryo 0.2 0.3 0.4 0 0 0 0 0 0 0.1Fetus 0.1 0.15 0.2 0.53 0 0 0 0 0 0.02Neonate 0.05 0.075 0.1 0.265 0.5 0 0 0 0 0.01Juvenile 0 0.05 0.06 0.13 0.25 0.5 0 0 0 0.01Adolescent 0 0 0 0.06 0.125 0.25 0.485 0 0 0.08Young Adult 0 0 0 0 0.06 0.125 0.25 0.315 0 0.25Old Adult 0 0 0 0 0 0.06 0.12 0.16 0.04 0.62Senescent 0 0 0 0 0 0 0 0 0.08 0.92Death 0 0 0 0 0 0 0 0 0 1
Stage n+1Pre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
40 40 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
40 40 0 0 0 0 0 0 0 20
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
2) The chronic disease modelThe accordionThe bagpipe
uniform expansionexpansion at one stage
Which stage has the greatest potential for expanding longevity? has the lowest death rate?
simulating change
QuickTime™ and aTIFF (LZW) decompressor
are needed to see this picture.
Gavrilov, Leonid A. and Natalia S. Gavrilova, The Biology of Life San: A Quantitative Approach. Revised and updated English Edition; 1991, pg. 164. Used with permission
The actually observed graph of mortality against age. The dependence of the force of mortality on age for Swedish women in 1980. Source of the data: Befolkningsförändingar, 1980.
Designation IntervalEarly fetal death Under 20 weeks of gestationIntermediate fetal death 20–27 weeks of gestationLate fetal death 28 or more weeks of gestationPerinatal death (1) 28 weeks of gestation to 7th day after birth
(2) 20 weeks of gestation to 28th day after birthNeonatal death Under 28 days after birthPost neonatal death 28 days to end of first year of lifeInfant death Under one year after birth
Fetal death and infant mortality
Chiang, Chin Long, The Life Table and Its Applications. Malabar, FL: Robert E. Krieger; 1984.
Chiang, Chin Long, The Life Table and Its Applications. Malabar, FL: Robert E. Krieger; 1984.
Number
of live Under Under Fetal Maternalbirths All ages 1 year 28 days deaths deaths
United States 3,326,632 1,899,597 46,975 32,860 33,053 373
fraction live births 0.0141209 0.0098779 0.0099359 0.0001121
Number of Deaths
Live births, total deaths, infant and neonatal deaths and fetal deaths
juvenile
age
neonate
senescent
old adultyoung adult
adolescent
embryo
fetus
stage
death
extension of the juvenile
stage to later stages of the
lifetime
Bagpipe: bStage N
Pre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death100 0 0 0 0 0 0 0 0 0
ToPre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
From Pre-embryo 0 0.8 0 0 0 0 0 0 0 0.2Embryo 0 0 0.8 0 0 0 0 0 0 0.1Fetus 0 0 0 0.98 0 0 0 0 0 0.02Neonate 0 0 0 0 0.99 0 0 0 0 0.01Juvenile 0 0 0 0 0.999 0 0 0 0 0.001Adolescent 0 0 0 0 0 0 0 0 0 0Young Adult 0 0 0 0 0 0 0 0 0 0Old Adult 0 0 0 0 0 0 0 0 0 0Senescent 0 0 0 0 0 0 0 0 0 0Death 0 0 0 0 0 0 0 0 0 0
Stage n+1Pre-embryo Embryo Fetus Neonate Juvenile Adolescent Young Adult Old Adult Senescent Death
0 80 0 0 0 0 0 0 0 20 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 80 0 0 0 0 0 0 0 20
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
Pre-embryo
Embryo
Fetus
Neonate
Juvenile
Adolescent
Young Adult
Old Adult
Senescent
Death
pg.
pg.
Juvenilization: the expansion of youthful anatomy and physiology to the later stages of a lifetime, i.e., ‘forever young.’
Progenesis: “precocious sexual maturation with other somatic tissues at their usual state of immature development for that age
Neoteny or fetalization: “sexual maturation at the usual age, but with retarded development of the other somatic tissues.”*
*: Finch, C.E., Longevity, Senescence, and the Genome. Chicago: The University of Chicago Press; 1990, pg. 629.
Paedogenesis: “sexual maturity occurs before the organism reaches the full size or relative proportions (shape) of closely related species.”*
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
2) The chronic disease modelThe accordionThe bagpipe
Is there a biological explanation?
3) Hypotheses for testing
simulating changeThe accordion: uniform expansionThe bagpipe: expansion at one stage
neoteny the^
Increasing lifespanDecreasing fecundity
3) Hypotheses for testing
slope of adult mortality curve should be dropping in the direction of the juvenile mortality curve
morphological features of the juvenile should be preserved and extended.
• juvenile state of growth and modulation of bone should not be brought to a halt
• thymic involution, with all its consequences for the immune response should be retarded, delayed, or even suspended
Genetics: (polygenic) Mendelian control
Epigenetics: NonMendelian heritability
Environment: Directly inducibleHow might a lifetime be juvenilized and a lifespan
lengthened?
Twin studies: Lifespan heritability
Maximum longevity possible or lifespan limits: the compensation effect of mortality
Genetics: (polygenic) Mendelian control
Experimental genetics of so-called model organisms
Pedigrees and familial correlations at the age of death
Juvenile phase spread by acquisition and accumulation of pro-juvenile mutations and elimination or dilution of anti-juvenile and aging Mendelian genes.
Juvenile phase spread by acquisition and accumulation of pro-juvenile mutations and elimination or dilution of anti-juvenile and aging Mendelian genes.
Genetics: (polygenic) Mendelian control
Environment: Directly inducibleJuvenile phase enhanced by external conditions such as hypothermia, nutritional deprivation and stress (not adversity).
Pressures and tensions on metabolic regulation, reproductive control, the inhibition of cellular proliferation, and the promotion of programmed cell death.
“the transcriptional equivalent of the fountain of youth”
The stem cell “fountain of youth” or “antithesis of aging,”
Adult stem cells continuously restore vigor to tissues and organs by replacing effete cells while, at the same time, renewing the adult stem-cell population.
Reserve stem cells respond to stress by regenerating damaged tissue and renewing their population.
“redundant elements that function as backups in the event of failure”
Genetics: (polygenic) Mendelian control
Epigenetics: NonMendelian heritability
Environment: Directly inducible
Juvenile phase expanded by changes that increase robustness and diminution of frailty but are not inherited according to the rubric of Mendelian genetics.
Juvenile phase spread by acquisition and accumulation of pro-juvenile mutations and elimination or dilution of anti-juvenile and aging Mendelian genes.
Juvenile phase enhanced by hypothermia, nutritional deprivation and stress (not adversity).
Lamarckian^
Epigenetics:
DNA methylation
Delayed DNA methylation
DNA de-methylation
* Wikipedia, The Free Encyclopedia: http://en2.wikipedia.org/wiki/Main+Page
* The study of heritable changes in gene function that occur without a change in the sequence of nuclear DNA. This includes the study of how environmental factors affecting a parent can result in changes in the way genes are expressed in the offspring.
* The study of the processes involved in the unfolding development of an organism. This includes phenomena such as X chromosome inactivation in mammalian females, and gene silencing within an organism.
Do adult and reserve stem cells share a common origin with embryonic germ cells in the embryonic stem cell population?
Are epigenetic influences nudging embryonic stem-cells away from the germ line?
Are longevity and fecundity functions of stem cell allocation in adults?
In sum:
Changes in lifespan and fecundity are due to changes in the allocation of stem-cells.
Is Homo sapiens evolving before our eyes, and can we analyze this evolution as it happens? 1) The already known
Increasing lifespanDecreasing fecundity
3) Hypotheses for testing
Is there a biological explanation?neoteny the
^
Shostak, S., 2004.