3. Ò San Bushmen live
in Botswana.
Ò They have some of
the oldest human
genes carried in
their DNA.
The beginning…………
4. Ò San Bushmen are expert
trackers and hunters
Ò They hunt different kinds
of animals.
Ò San Bushman have an
unique language- the
click language
Ò And weapons that gave
them a hunting
advantage 50,000 years
ago http://news.nationalgeographic.com/news/2002/12/photogalleries/journey_of_man/
The amazing story of the san bushmen
6. But how do we know That this
Journey started in africa?
?
7. We know because we can trace certain
Dna markers from human populations
Y-chromosome markers take us ~59,000
Years back into history
These markers lead us straight back
To the san bushmen
M168, m130
8. Markers on dna
A marker on DNA is a landmark that tells you where you
are in the genome
9. Mitochondrial eve and female
Mitochondrial markers
http://images.sciencedaily.com/2010/08/100817122405.jpg
10. Ó Mitochondria -- the tiny organelles that
serve as energy factories inside all human
cells -- have their own genome. Besides
containing 37 genes that rarely change, they
contain a "hypervariable” (HVR) region,
which changes fast enough to provide a
molecular clock calibrated to times
comparable to the age of modern humanity.
Ó Because each person's mitochondrial
genome is inherited from his or her mother,
all mitochondrial lineages are maternal.
Ó To infer mt Eve's age, scientists must
convert the measures of relatedness
between random blood donors into a
measure of time to translate the differences
between gene sequences into how they
evolved in time
Mitochondrial dna
11. Mitochondrial haplogroups
A mtDNA haplogroup is
defined as all of the female
descendants of the single
person who first showed a
particular polymorphism, or
SNP.
SNP: Single nucleotide
polymorphism- change in a
single base of DNA
mtDNA SNP identifies a group
who share a common
ancestor far back in time. SNP
markers are found in all 3
regions of the mtDNA: HVR-1,
HVR-2 and coding region
http://64.40.115.138/file/lu/6/52235/NTIyMzV9K3szNDExNzY=.jpg?download=1
12. Mapping snp’s on mt dna
A SNP is like a landmark or
marker on DNA which you can
follow to find the same marker
(or sets of markers) in other
individuals.
Mitochondria eve had all the
human sets of markers
indicating the root of humans
13. Mapping snp’s on mt dna
A SNP is like a landmark or marker on DNA
14. SNPs have reference numbers:
rs267601453 - rs stands for reference
SNP
dataBase SNP
http://www.ncbi.nlm.nih.gov/projects/SNP/
15. Mapping snp’s on mt dna
http://upload.wikimedia.org/wikipedia/commons/thumb/9/92/MtDNA-MRCA-generations-Evolution.svg/220px-MtDNA-MRCA-generations-Evolution.svg.png
19. Mitochondrial haplogroups
mtDNA analyses provided our first genetic window into the past, detailing the history of maternal lineages
across human populations. The oldest mtDNA haplogroups are found in Africa (L1, L2 and L3; see figure).
The pan-African haplogroup L3 radiated to form MACROHAPLOGROUPS M and N. Macro-haplogroups M
and N arose in North Eastern Africa, and individuals that had M and N mtDNA subsequently left Africa to
colonize Europe and Asia approx60,000–80,000 years ago
20. Mitochondrial haplogroups
Haplogroups H, I, J, N1b, T, U, V, W and X are mainly derived from macrohaplogroup N and make up almost
all of the mtDNA types found in Europe. In Asia, macrohaplogroups N and M radiated to generate mtDNA
lineages A, B, C, D, F and G. Native Americans are known to have Asian ancestry because only five
haplogroups (A, B, C, D and X) encompass all of the mtDNA variation in the New World, four of which came
from Asia67.
21. Africa: the cradle of life
We can also map markers
on the Y - chromosome
Both The mitochondrial dna and
Y-chromosomal dna has less dna
To deal with hence they were
Initially chosen
Now we can sequence entire
genomes In the space of a single
day
22. Africa: the cradle of life
We can also map markers
on the Y - chromosome
Which still takes us back
to Africa but only about
59,000 years ago
23.
24. Technique of Mapping Y chromosome Markers
Y-DNA testing involves looking at STR segments of DNA on the Y chromosome. The STR segments which
are examined are referred to as genetic markers and occur in what is considered "junk" DNA.
STR markers
A Y-chromosome contains sequences of repeating nucleotides known as short tandem repeats (STRs)/
microsatellites. The number of repetitions varies from one person to another and a particular number of
repetitions is known as an allele of the marker. Individual Y-DNA sequences or STRs which have proved useful
in genealogical DNA work are called markers, and each has a name, such as DYS393 in the following
example.
This example states that the DYS393 marker is 12, also called the marker's "value". The value 12 means the
DYS393 sequence of nucleotides is repeated 12 times—with a DNA sequence of (AGAT)12.
Y-DNA tests generally examine 10-67 STR markers on the Y chromosome, but over 100 markers are available.
25. An example of a genealogical test: STR mapping on Y chr
29. • 2000 generations ago (50-60 Kya) behaviorally advanced
Homo sapiens - the direct ancestors of San and Hadzabe
Bushmen were driven by drought to follow their
quarry searching for grasslands out of Africa.
EVIDENCE:
• The click language of the San and Hadzabe does not
exist elsewhere in the world
• DNA Marker- M168
The journey out of africa
30. All modern humans were in Africa
Until around ~60,000 years ago
http://www.geographicguide.com/pictures/maps/africa-globe.gif
You were here!
31. On with the journey……….
And so the journey continued
through asia along the coastal route
and to the continent
of australasia
http://cfile215.uf.daum.net/image/1227331C4C57DFF432373B
32. Ò Before a group of the
descendents of the San
Bushmen entered Australia
they passed through India
Ò Spencer Wells took DNA
samples and found a
marker that traces back to
the San Bushmen tribe.
Tracing a route through india
33. This African haplogroup
marker takes us to the
temple city of Madurai in
the Tamil Nadu district in
southern India where
genomic screening from a
man shows a single
nucleotide ancient
bloodmarker in his Y
chromosome leading back
to the San. This is also the
site where the earliest
archaeological evidence of
behaviorally modern Homo
sapiens has been found.
Tracing a route through india
34. Ò Open water along the route was
crossed by simple rafts made of logs
Ò The route out of Africa is hypothesized
to lead to Southern India then on to
Sri Lanka and then Indonesia
On to australia
35. The next genetic evidence
for descendants out of
Africa shows up at a 45
Kya site in Lake Mungo at
Laura in Queensland,
Australia. Somehow the
aboriginal's ancestors were
able to complete the
journey (the drop in sea
level that provided a
continuous land route
through Indonesia but still
left a 150 mile wide stretch
of open sea to reach the
continent.)
Africa to australia in 20-15000 years
Following the m130
41. Ò A group of people
from Africa went
North to Kazakhstan.
Ò Spencer Wells found
a man here with a
genetic marker from
the people of the
San Bushmen tribe
To kazakhstan………
42. Ò From
Kazakhstan
people
migrated to all
parts of Asia
and started to
multiply.
Ò From here a
group of
people went
North to
Siberia and
adapted to
live in cold
climates.
Central asia: the M45 marker
43. About 40,000 years ago sapiens have spread to central asia following the grasslands
resulting from cooling climate. An episode of migrations begins that moves people from
central Asia - two groups moved east to China's north and south and another group
moves down to India. It will take another five thousand years before the first people
from central Asia migrate to Europe
Wells' earlier expedition in 1998 had provided blood samples from Uzbekistan,
Kyrgyzstan, and Kazakhstan and he reconnects with a man named Niyazov -a Kazakh
Turk who lives in Kazakhstan near the border of Kirgyzistan. Niyazov has African
markers that go back 2000 generations and also has an important Y chromosome
marker called M45. That indicates Central Asia is where M45 originated and where
both Europeans and Native Americans were descendant from.
40,000 years ago - we reach central asia
44. The Hub for migration: into europe
35,000 ya
40,000 ya
45. That marker (M45) is carried
by people migrating to the
Siberian arctic - ancestors of
the contemporary Chukchi-
nomadic reindeer herders
whose entire sustenance is
derived from lichen growing on
the permafrost.
The expedition goes to town of
Ague in Siberia and travels via
helicopter and converted
Russian tank to Chukchi
encampment 200 mi north of
the arctic circle.
Following the m45
46. Ò These people live in
the Arctic Circle.
Ò They herd reindeer
The chukchi
47. Ò They have
smaller limbs
and a shorter
trunk.
Ò This structure
retains heat the
best.
Ò These people
adapted to the
extreme
environment.
The chukchi
USARussia:
home of the chukchi
48. 20,000 ya
13,000 ya
10-12,000 ya
20,000 ya, a group of their ancestors, an
original tribe of perhaps 20-30 individuals
journeyed across Beringia to N Alaska at the
height of the ice age when temperatures got
as cold (-60 below) as at any time in the
human odessey. Here they settled for
thousands of years trapped from further
migration south by Alaskan glaciers.
Around 13,000 ya as the ice age waned, a
corridor opened up that allowed a small
band consisting of as few as 2 males in a
group of a dozen individuals to migrate
south.
In less than 1000 years, all of N and S
America were populated by their
descendants - from Inuit to Inca - with the
Chukchi haplogroup marker.
Into the americas
49. Ò These people have their own
stories of creation
Ò They believe that they came
from the Earth
Ò They are descendents of the
Chukchi people
The Navajo
50. Ò People then
traveled and
populated from
North America
all the way down
to the south
peak of South
America.
The longest journey:
50,000 years and we reach south america
51. The ~50,000 year journey to reach
south america
40,000 ya
60,000 ya
20,000 ya
13,000 ya
10-12,000 ya
56. Ò People look
different because of
isolation and
adaptations to
different
environments
Ò Underneath all of
that we are the
same
we are all connected
We are the same
57. Never forget that
we share 99.9% of
Our Dna with
every single
person On
this earth
58. The Journey of Man by Spencer Wells
http://genographic-project.wikispaces.com/
https://genographic.nationalgeographic.com/human-journey/
References
