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HUMAN GENETIC ADAPTATION TO
HIGH ALTITUDE
Catherine Godinot
Physiological adaptation versus
genetic selection
•
Aclimatization :
– Immediate
– Days
– Years
•
Development
– Before birth, during growth
•
Genetic selection
Over many generations :
– Increased fecondity, improved or decreased survival during
embryogenesis and after birth
– Resistance to diseases
– Gene polymorphism selection
•
Relations Polymorphisms !" Adaptation to HA
Birth weight and Adaptation to Altitude
From Moore L (2004) Placenta Supplement A Trophobalst research, 18, S60-S71
Physiological adaptation versus
genetic selection
•
Aclimatization :
– Immediate
– Days
– Years
•
Development
– Before birth, during growth
•
•
Genetic selection
Over many generations :
–
Increased fecondity, improved or decreased survival during embryogenesis and
after birth
–
Resistance to diseases
–
Gene polymorphism selection
Relations Polymorphisms !" Adaptation to HA
Factors involved in oxygen availability
to tissues implying many genes
O2 in atmosphere
LUNG PUMPING
OXYGEN TRANSPORT
Lung alveoles
HEMOGLOBIN CONTENT
and AFFINITY TO OXYGEN
ARTERIAL OXYGEN CONTENT
Arterial Blood
HEART PUMPING
REGIONAL BLOOD FLOW
Whole body capillaries
ORGAN BLOOD FLOW
VASCULAR NETWORK
Tissue, Permeability
Proteins binding and metabolizing oxygen
METABOLISM
Mitochondria
Density and Distribution
Activities of enzymes using oxygen: cytochrome oxidase and Reactive Oxygen Species
Possible Genetic Adaptation of
High Altitude Andean populations
From Rupert and Hochachka (2001) High altitude Medecine and Biology, 2, 235-256)
Physiological adaptation versus
genetic selection
•
Aclimatization :
– Immediate
– Days
– Years
•
Development
– Before birth, during growth
•
•
Genetic selection
Over many generations :
–
Increased fecondity, improved or decreased survival during embryogenesis and
after birth
–
Resistance to diseases
–
Gene polymorphism selection
Relations Polymorphisms !" Adaptation to HA
Nitric oxide synthase
- NO drops for lowlanders upon acute exposure to low oxygen
- However, exhaled NO is higher in Tibetans and Andeans in spite of their
higher hemoglobin contents
- Oxygen inspiration increased exhaled NO in Tibetans but not in Andeans
suggesting different mechanisms and genetic influence
- Functional advantage of High NO: enhanced oxygen uptake in lungs,
hence improving oxygen delivery to tissues
Exhaled NO (ppb)
Standard
(n)
After oxygen
Inspiration
(42-50 %)
Tibetans
Andeans
(4,200 m)
(3,900 m)
18.6
(105)
p<0.001
21.1
(26)
p<0.05
9.5
(144)
p<0.01
Low-landers
(USA)
7.4
(33)
9.6
(25)
p>0.05
Adapted from Beall et al (2001) Nature, 414, 411-412
Factors involved in oxygen availability
to tissues implying many genes
O2 in atmosphere
LUNG PUMPING
OXYGEN TRANSPORT
Lung alveoles
HEMOGLOBIN CONTENT
and AFFINITY TO OXYGEN
ARTERIAL OXYGEN CONTENT
Arterial Blood
HEART PUMPING
REGIONAL BLOOD FLOW
Whole body capillaries
ORGAN BLOOD FLOW
VASCULAR NETWORK
Tissue, Permeability
Proteins binding and metabolizing oxygen
METABOLISM
Mitochondria
Density and Distribution
Activities of enzymes using oxygen: cytochrome oxidase and Reactive Oxygen Species
ADP + Pi
--> ATP
Historical, Archeological, linguistic,
geographic influence on Genetic drift
• Time of residence in HA and specific genetic adaptations:
Tibetans >Andeans >Europeans >Han-Chinese >
Ethiopians
• Genetic drift
– Loss of genetic variation due to low population size:
founder effect
– Gene flow: introduction of new genes by admixture
inbreeding
– Population migration: example with mtDNA analysis
• Analysis of ancient and contemporary materials: case of
ancient mummies
Specific adaptations to high altitude in
different populations
From Beall et al, (2002) Proc. Natl Acad Sci 99, 17215-17218
Historical, Archeological, linguistic,
geographic influence on Genetic drift
• Time of residence in HA:
Tibetans >Andeans >Europeans >Han-Chinese >
Ethiopians
• Genetic drift: case of Andean Populations (languages, Inca
empire, european admixture, ancestor diversity)
– Loss of genetic variation due to low population size:
founder effect?
– Gene flow: introduction of new genes by admixture
inbreeding?
– Population migration: example with mtDNA analysis
• Analysis of ancient and contemporary materials: case of
ancient mummies
Human mitochondrial DNA Migrations
http://www.mitomap.org/mitomap/WorldMigrations.pdf
Mitochondrial DNA inheritance
Major mtDNA haplogroup branches
Human Mitochondrial DNA
PH
12S
OH
F
T
D-loop
V
PL
16S
Cyt b
HAPLOTYPE A
+Hae III 663
P
E
OH
PH
12S
ND6
F
V
T
D-loop
PL
HAPLOTYPE C
+Hinc II 13259
E
16S
L
Cyt b
P
ND6
ND5
L
ND1
ND5
ND1
I
L
S
H
Q
M
ADN mt
HAPLOTYPE DI
M
-Alu I 5176
ND2
W
ND2
W
AN
CY
ND4
16569 pb
Q
AN
CY
ND4
OL
R
S
G
CO I
OL
R
S
G
CO I
D
CO II
K
CO III
ATPase 8/6
ND4L
ND3
L
S
H
D
CO II
K
CO III
ATPase
8-6
9 pb-deletion
HAPLOTYPE B
ND4L
ND3
• Oxydative phosphorylations
Matrice
Cycle de
Krebs
H+
H
NADH+H+
fumarate
NAD+
H+
III
II
FMN
UQH2
[FeS]
[FeS]
IV
UQ.Cyt b560
H2O
UQ
F1
V
CuB-Cyt a3
Cyt a
Fo
Cyt b566
[FeS]
UQH2
UQ.[FeS]
H+
Cyt c1 Cyt c
CuA
UQ
Cyt c
H+
succinate
déshydrogénase
NADH
déshydrogénase
7
39
1/2O2+2H+
H++
FAD
I
0
4
ATP
ADP+Pi
succinate
H+
H+
Espace intermembranaire
Ubiquinol
cytochrome c
réductase
1
10
cytochrome c
ATPaseoxydase ATPsynthétase
3
10
2
14
ADN mt
ADN nucléaire
Historical, Archeological, linguistic,
geographic influence on Genetic drift
• Time of residence in HA:
Tibetans >Andeans >Europeans >Han-Chinese >
Ethiopians
• Genetic drift
– Loss of genetic variation due to low population size:
founder effect
– Gene flow: introduction of new genes by admixture
inbreeding
– Population migration: example with mtDNA analysis
• Analysis of ancient and contemporary materials: case of
ancient mummies
Methods to distinguish
Physiological/Environmental influence
from Genetic selection
• Compare differences between two isolated populations
• Investigate differences between monozygotic and dizygotic
twins
• Compare a physiological trait to frequency of presence of a
gene allele by linkage disequilibrium approach
• Map chromosomal regions involved in regulation of
physiological trait: FISH analysis
• Candidate gene approach
Methods to distinguish
Physiological/Environmental influence
from Genetic selection
• Compare differences between two isolated populations
• Investigate differences between monozygotic and dizygotic
twins
• Compare a physiological trait to frequency of presence of a
gene allele by linkage disequilibrium approach
• Map chromosomal regions involved in regulation of
physiological trait: FISH analysis
• Candidate gene approach
Methods to distinguish
Physiological/Environmental influence
from Genetic selection
• Compare differences between two isolated populations
• Investigate differences between monozygotic and dizygotic
twins
• Compare a physiological trait to frequency of presence of a
gene allele by linkage disequilibrium approach
• Map chromosomal regions involved in regulation of
physiological trait: FISH analysis
• Candidate gene approach
Northern and Southern Blotting (1)
Southern Blotting (2)
LOD SCORE
No Linkage
Recombination frequency 50%
θ = 0.5
Genetic distance> 50 cMorgan
Linkage
Recombination frequency 0%
θ=0
Genetic distance: 0 cMorgan
Lod score:Zθ=log10*(Lθ/Lθ0.5)
Methods to distinguish
Physiological/Environmental influence
from Genetic selection
• Compare differences between two isolated populations
• Investigate differences between monozygotic and dizygotic
twins
• Compare a physiological trait to frequency of presence of a
gene allele by linkage disequilibrium approach
• Map chromosomal regions involved in regulation of
physiological trait: FISH analysis
• Candidate gene approach
FISH: gene visualisation on chromosomes
Examples of FISH experiments
FISH: probe to telomeres
FISH: probe to a unique gene
on chromosome 7
Mutation detection with microarrays
(AFFYMETRIX)
Methods to distinguish
Physiological/Environmental influence
from Genetic selection
• Compare differences between two isolated populations
• Investigate differences between monozygotic and dizygotic
twins
• Compare a physiological trait to frequency of presence of a
gene allele by linkage disequilibrium approach
• Map chromosomal regions involved in regulation of
physiological trait: FISH analysis
• Candidate gene approach
Birth weight and Adaptation to Altitude
From Moore L (2004) Placenta Supplement A Trophobalst research, 18, S60-S71
Endothelin 1
Endothelin 1, a potent vasoconstrictor is differentially regulated by pregnancy and
chronic hypoxia in Andean versus European residents of High Altitude. SNPs in
the ET-1 gene also differ in Andeans compared to low-altitude populations.
Example of natural selection acting on one of the HIF-targeted genes.
Other candidate genes near HIF-regulated genes exhibiting different allele
frequencies between Quechua Nahua and East-Asians identified with the
Affymetrix chip : NOSII, PHD3, α-adrenergic receptor
From Moore L (2004) Placenta Supplement A Trophobalst research, 18, S60-S71
Potential genetic influence on HAPE
(High-Altitude Pulmonary Œdema)
From Mortimer et al, (2004) Pharmacology and Therapeutics, 101: 183-192
Angiotensin converting enzyme and
genetics at high altitude
Allele D: Deletion
Allele I: Insertion of 287
bp in intron 16
Mitochondrial DNA
- 5-15% EPA (excessive Polycythemia
of Altitude) incidence in Bolivians
-5-15% non B Haplotypes (A or C)
HAPLOTYPE A
+Hae III 663
OH
PH
12S
F
V
T
D-loop
Cyt b
P
PL
HAPLOTYPE C
+Hinc II 13259
E
16S
ND6
L
ND5
ND1
ADN mt
HAPLOTYPE DI
M
-Alu I 5176
16569 pb
Q
ND2
W
AN
CY
L
S
H
ND4
OL
R
S
G
CO I
D
CO II
K
CO III
ATPase
8-6
9 pb-deletion
HAPLOTYPE B
- A or C mtDNA haplogroups are not found
in Tibetans rarely suffering of EPA
ND4L
- Different SNPs in B versus A or C
haplotypess in CO I and COII
ND3
- Regulation of COX synthesis by HIF
- Similarities between development of EPA
and of some mitochondrial diseases
during adult life.
HAPLOGROUP DISTRIBUTION
IN CONTROLS AND EPA PATIENTS
100%
%C
80%
%A
60%
%B
40%
20%
0%
C1
C2
C3
EPA I
EPA II
C total EPA I+II
Excessive Erythrocytosis of Altitude(EPA) in relation
to mtDNA haplogroups in Bolivian Aymaras?
CONCLUSIONS
#Many arguments converge to convince us that genetic events
have occurred to better adapt humans in high altitude areas after their
initial settlement. Genetic adaptation is very likely different from one
place to the other.
#In spite of many efforts, the number of conclusively identified genes
remains low. A lot more is to be done to understand the different paths
that nature has found to improve life in High Altitude!
# New tools are there and being further developed to accelerate this
type of research due to knowledge of whole human genome
#One of the most difficult tasks remains the selection of adequate
populations:
-isolated populations become rare
-incidence of external factors to develop an adaptation or a disease
and hence risk of poor selection of subjects to be analyzed
-an excellent knowledge of the physio-pathological status of these
populations is an absolute requirement
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Catherine Godinot
Hélène Simonnet
Eric Hervouet
Jocelyne Demont
Franck Dragounoff
Elodie Coujard de
Laplanche
• Institut Bolivien de Biologie
d’Altitude, La Paz, BOLIVIE
–
–
–
–
–
–
Enrique Vargas
Fabrice Rossignol
Elfride Balanza
Enma Ruiz
Mercedes Villena
Ivette Rodriguez
High altitude and capillary density in
placentas
Immunohistochemical staining using antiCD34
staining and hematoxylin background stain
Tyrosine Hydroxylase
Traditional genetic tools
Genetic engineering
– Restriction site maps
•(0,001 à 0,02 Megabases)
– Cloning
•vectors : plasmids,
phages, cosmids
•(insert size : 0,001 à 0,05
Megabases
Physical map
Classical genetic
– Lod score
•1 cMorgan ~ 1 Megabase
– Gene localization on
chromosomes (FISH)
•precision ~ 10 Megabases
Genetic map
Mutation detection with synthetic probes
Variations physiopathologiques de la
biogenèse mitochondriale
•
•
•
•
Développement : exemple de C. elegans
Vieillissement
Exercice musculaire
Maladies mitochondriales : prolifération (RRF) ou
déplétion de l’ADNmt
• Baisse des activités OXPHOS dans la plupart des
cancers sauf dans les oncocytomes
Evolution du contenu en ADNmt
au cours de la vie de C. elegans
Selon Tsang et Lemire (2002)