Haplogroup T - Journey to Today

Your DNA results identify you as belonging to a specific branch of
the human family tree called haplogroup T.
Haplogroup T contains the following subgroups: T, T1, T2, T2b, T3,
T4, T5.
The map above shows the direction that your maternal ancestors took
as they set out from their original homeland in East Africa. While
humans did travel many different paths during a journey that took
tens of thousands of years, the lines above represent the dominant
trends in this migration.
Over time, the descendants of your ancestors ultimately made it into
northeastern Europe, where most members of your haplogroup are found
today. But before we can take you back in time and tell their
stories, we must first understand how modern science makes this
analysis possible.
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How DNA Can Help
The string of 569 letters shown above is your mitochondrial
sequence, with the letters A, C, T, and G representing the four
nucleotides the chemical building blocks of life that make up your
DNA. The numbers at the top of the page refer to the positions in
your sequence where informative mutations have occurred in your
ancestors, and tell us a great deal about the history of your
genetic lineage.
Here's how it works. Every once in a while a mutation a random,
natural (and usually harmless) change occurs in the sequence of your
mitochondrial DNA. Think of it as a spelling mistake: one of the
"letters" in your sequence may change from a C to a T, or from an A
to a C.
(Explore the Genetics Overview to learn more about population
genetics.)
After one of these mutations occurs in a particular woman, she then
passes it on to her daughters, and her daughters' daughters, and so
on. (Mothers also pass on their mitochondrial DNA to their sons, but
the sons in turn do not pass it on.)
Geneticists use these markers from people all over the world to
construct one giant mitochondrial family tree. As you can imagine,
the tree is very complex, but scientists can now determine both the
age and geographic spread of each branch to reconstruct the
prehistoric movements of our ancestors.
By looking at the mutations that you carry, we can trace your
lineage, ancestor by ancestor, to reveal the path they traveled as
they moved out of Africa. Our story begins with your earliest
ancestor. Who was she, where did she live, and what is her story?
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Your Ancestral Journey: What They Know Now

We
will now take you back through the stories of your distant ancestors
and show how the movements of their descendants gave rise to your
mitochondrial lineage.
Each segment on the map above represents the migratory path of
successive groups that eventually coalesced to form your branch of
the tree. We start with your oldest ancestor, "Eve," and walk
forward to more recent times, showing at each step the line of your
ancestors who lived up to that point.
(Click
here to Explore our Route Map
in a separate browser window along side our haplogroup's ancestral journey.)
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Mitochondrial Eve: The Mother of Us All
Ancestral Line: "Mitochondrial Eve"
Our story begins in Africa sometime between 150,000 and 170,000
years ago, with a woman whom anthropologists have nicknamed
"Mitochondrial Eve."
She was awarded this mythic epithet in 1987 when population
geneticists discovered that all people alive on the planet today can
trace their maternal lineage back to her.
But "Mitochondrial Eve" was not the first female human.
Homo sapiens
evolved in Africa around 200,000 years ago, and the first hominids
characterized by their unique bipedal stature appeared nearly two
million years before that. Yet despite humans having been around for
almost 30,000 years, Eve is exceptional because hers is the only
lineage from that distant time to survive to the present day.
Which begs the question, "So why Eve?"
Simply put, Eve was a survivor. A maternal line can become extinct
for a number of reasons. A woman may not have children, or she may
bear only sons (who do not pass her mtDNA to the next generation).
She may fall victim to a catastrophic event such as a volcanic
eruption, flood, or famine, all of which have plagued humans since
the dawn of our species.
None of these extinction events happened to Eve's line. It may have
been simple luck, or it may have been something much more. It was
around this same time that modern humans' intellectual capacity
underwent what author Jared Diamond coined the
Great Leap Forward.
Many anthropologists believe that the emergence of language gave us
a huge advantage over other early human species. Improved tools and
weapons, the ability to plan ahead and cooperate with one another,
and an increased capacity to exploit resources in ways we hadn't
been able to earlier, all allowed modern humans to rapidly migrate
to new territories, exploit new resources, and out compete and
replace other hominids, such as the Neandertals.
It is difficult to pinpoint the chain of events that Led to Eve's
unique success, but we can say with certainty that all of us trace
our maternal lineage back to this one woman.
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The L Haplogroups: The Deepest Branches
Ancestral line: "Eve" > L1/L0
Mitochondrial Eve represents the root of the human family tree. Her
descendents, moving around within Africa, eventually split into two
distinct groups, characterized by a different set of mutations their
members carry.
These groups are referred to as L0 and L1, and these individuals
have the most divergent genetic sequences of anybody alive today,
meaning they represent the deepest branches of the mitochondrial
tree. Importantly, current genetic data indicates that indigenous
people belonging to these groups are found exclusively in Africa. This means that, because all humans have a common female ancestor,
"Eve," and because the genetic data shows that Africans are the
oldest groups on the planet, we know our species originated there.
Haplogroups L1 and L0 likely originated in East Africa and then
spread throughout the rest of the continent. Today, these lineages
are found at highest frequencies in Africa's indigenous populations,
the hunter-gatherer groups who have maintained their ancestors
culture, language, and customs for thousands of years.
At some point, after these two groups had coexisted in Africa for a
few thousand years, something important happened. The mitochondrial
sequence of a woman in one of these groups, L1, mutated. A letter in
her DNA changed, and because many of her descendants have survived
to the present, this change has become a window into the past. The
descendants of this woman, characterized by this signpost mutation,
went on to form their own group, called L2. Because the ancestor of
L2 was herself a member of L1, we can say something about the
emergence of these important groups: Eve begat L1, and L1 begat
L2,
Now we're starting to move down your ancestral line.
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Haplogroup L2: West Africa
Ancestral line: "Eve" > L1/L0 > L2
L2 individuals are found in sub-Saharan Africa, and like their L1
predecessors, they also live in Central Africa and as far south as
South Africa. But whereas L1/L0 individuals remained predominantly
in eastern and southern Africa, your ancestors broke off into a
different direction, which you can follow on the
map above.
L2 individuals are most predominant in West Africa, where they
constitute the majority of female lineages. And because L2
individuals are found at high frequencies and widely distributed
along western Africa, they represent one of the predominant lineages
in African-Americans. Unfortunately, it is difficult to pinpoint
where a specific L2 lineage might have arisen. For an
African-American who is L2 the likely result of West Africans being
brought to America during the slave trade it is difficult to say
with certainty exactly where in Africa that lineage arose.
Fortunately, collaborative sampling with indigenous groups is
currently underway to help Learn more about these types of questions
and to possibly bridge the gap that was created during those
transatlantic voyages hundreds of years ago.
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Haplogroup L3: Out of Africa
Ancestral line: "Eve" > L1/L0 > L2 > L3
Your next signpost ancestor is the woman whose birth around 80,000
years ago began haplogroup L3. It is a similar story: an individual
in L2 underwent a mutation to her mitochondrial DNA, which was
passed onto her children. The children were successful, and their
descendants ultimately broke away from the L2 clan, eventually
separating into a new group called L3. You can see above that this
has revealed another step in your ancestral line.
While L3 individuals are found all over Africa, including the
southern reaches of sub-Sahara, L3 is important for its movements
north. You can follow this movement of the map above, seeing first
the expansions of L1/L0, then L2, and followed by the northward
migration of L3.
Your L3 ancestors were significant because they are the first modern
humans to have left Africa, representing the deepest branches of the
tree found outside of that continent.
Why would humans have first ventured out of the familiar African
hunting grounds and into unexplored lands? It is likely that a
fluctuation in climate may have provided the impetus for your
ancestors' exodus out of Africa.
The African Ice Age was characterized by drought rather than by
cold. Around 50,000 years ago the ice sheets of northern Europe
began to melt, introducing a period of warmer temperatures and
moister climate in Africa. Parts of the inhospitable Sahara briefly
became habitable. As the drought-ridden desert changed to savanna,
the animals your ancestors hunted expanded their range and began
moving through the newly emerging green corridor of grasslands.
Your nomadic ancestors followed the good weather and plentiful game
northward across this Saharan Gateway, although the exact route they
followed remains to be determined.
Today, L3 individuals are found at high frequencies in populations
across North Africa. From there, members of this group went in a few
different directions. Some lineages within L3 testify to a distinct
expansion event in the
mid-Holocene that headed south, and are
predominant in many Bantu groups found all over Africa. One group of
individuals headed west and is primarily restricted to Atlantic
western Africa, including the islands of
Cabo Verde.
Other L3 individuals, your ancestors, kept moving northward,
eventually leaving the African continent completely. These people
currently make up around ten percent of the Middle Eastern
population, and gave rise to two important haplogroups that went on
to populate the rest of the world.
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Haplogroup N: The Incubation Period
Ancestral line: "Eve" > L1/L0 > L2 > L3 > N
Your next signpost ancestor is the woman whose descendants formed
haplogroup N. Haplogroup N comprises one of two groups that were
created by the descendants of L3.
The first of these groups, M, was the result of the first great wave
of migration of modern humans to leave Africa. These people likely
left the continent across the Horn of Africa near Ethiopia, and
their descendants followed a coastal route eastward, eventually
making it all the way to Australia and Polynesia.
The
second great wave, also of L3 individuals, moved north rather than
east and left the African continent across the Sinai Peninsula, in
present-day Egypt. Also faced with the harsh desert conditions of
the Sahara, these people likely followed the Nile basin, which would
have proved a reliable water and food supply in spite of the
surrounding desert and its frequent sandstorms.
Descendants of these migrants eventually formed haplogroup N. Early
members of this group lived in the eastern Mediterranean region and
western Asia, where they likely coexisted for a time with other
hominids such as
Neandertals. Excavations in Israel's Kebara Cave
(Mount Carmel) have unearthed Neanderthal skeletons as recent as
60,000 years old, indicating that there was both geographic and
temporal overlap of these two hominids.
The ancient members of haplogroup N spawned many sublineages, which
spread across much of the rest of the globe and are found throughout
Asia, Europe, India, and the Americas.
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Haplogroup R: Spreading Out
Ancestral line: "Eve" > L1/L0 > L2 > L3 > N > R
After several thousand years in the Near East, individuals belonging
to a new group called haplogroup R began to move out and explore the
surrounding areas. Some moved south, migrating back into northern
Africa. Others went west across
Anatolia (present-day Turkey) and
north across the
Caucasus Mountains of
Georgia and southern Russia. Still others headed east into the Middle East, and on to Central
Asia. All of these individuals had one thing in common: they shared
a female ancestor from the N clan, a recent descendant of the
migration out of Africa.
The story of haplogroup R is complicated, however, because these
individuals can be found almost everywhere, and because their origin
is quite ancient. In fact, the ancestor of haplogroup R Lived
relatively soon after humans moved out of Africa during the second
wave, and her descendants undertook many of the same migrations as
her own group, N.
Because the two groups lived side by side for thousands of years, it
is likely that the migrations radiating out from the Near East
comprised individuals from both of these groups. They simply moved
together, bringing their N and R lineages to the same places around
the same times. The tapestry of genetic lines became quickly
entangled, and geneticists are currently working to unravel the
different stories of haplogroups N and R, since they are found in
many of the same far-reaching places.
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Haplogroup T: Your Branch on the Tree
Ancestral line: "Eve" > L1/L0 > L2 > L3 > N > R > T
We finally arrive at your own clan, a group of individuals who
descend from a woman in the R branch of the tree. The divergent
genetic lineage that constitutes haplogroup T indicates that she
lived sometime around 40,000 years ago.
Haplogroup T has a very wide distribution, and is present as far
east as the
Indus Valley bordering India and Pakistan and as far
south as the Arabian Peninsula. It is also common in eastern and
northern Europe. Although your haplogroup was present during the
early and middle
Upper Paleolithic, T is largely considered one of
the main genetic signatures of the
Neolithic expansions.
While groups of hunter-gatherers and subsistence fishermen had been
occupying much of
Eurasia for tens of thousands of years, around ten
thousand years ago a group of modern humans living in the
Fertile
Crescent, present-day eastern Turkey and northern Syria began
domesticating the plants, nuts, and seeds they had been collecting. What resulted were the world's first agriculturalists, and this new
cultural era is typically referred to as the
Neolithic.
Groups of individuals able to support larger populations with this
reliable food source began migrating out of the Middle East,
bringing their new technology with them. By then, humans had already
settled much of the surrounding areas, but this new agricultural
technology proved too successful to ignore, and the surrounding
groups quickly copied these new immigrants. Interestingly, DNA data
indicate that while these new agriculturalists were incredibly
successful at planting their technology in the surrounding groups,
they were far Less successful at planting their own genetic seed. Agriculture was quickly and widely adopted, but the lineages carried
by these Neolithic expansions are found today at frequencies seldom
greater than 20 percent in Europe, the Middle East, and Central
Asia.
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Anthropology vs. Genealogy
DNA
markers require a long time to become informative. While mutations
occur in every generation, it requires at least hundreds normally
thousands of years for these markers to become windows back into the
past, signposts on the human tree.
Still, our own genetic sequences often reveal that we fall within a
particular sub-branch, a smaller, more recent branch on the tree.
While it may be difficult to say anything about the history of these
sub-groups, they do reveal other people who are more closely related
to us. It is a useful way to help bridge the anthropology of
population genetics with the genealogy to which we are all
accustomed.
One of the ways you can bridge this gap is to compare your own
genetic Lineage to those of people living all over the world.
Mitosearch.org is a database that allows you to compare both your
genetic sequence as well as your surname to those of thousands of
people who have already joined the database. This type of search is
a valuable way of inferring population events that have occurred in
more recent times (i.e., the past few hundred years).
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Looking Forward (Into
the Past): Where Do We Go From Here?
Although the arrow of your haplogroup currently ends across
sub-Saharan Africa, this isn't the end of the journey for haplogroup
T. This is where the genetic clues get murky and your DNA trail
goes cold. Your initial results shown here are based upon the best
information available today but this is just the beginning.
A fundamental goal of the Genographic Project is to extend these
arrows further toward the present day. To do this, Genographic has
brought together ten renowned scientists and their teams from all
over the world to study questions vital to our understanding of
human history. By working together with indigenous peoples around
the globe, we are learning more about these ancient migrations.
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Help Them Find More Clues!
But
there is another way that we will learn more about the past. By
contributing your own results to the project, you will be allowed to
participate anonymously in this ongoing research effort. This is
important because it may contribute a great deal to our
understanding of more recent human migrations.
Click the "Help Us Tell the Story"
link to learn more about how you can help science understand more
about how our ancestor migrated through history. It's
quick, easy, and anonymous, but will help us further refine our
analyses.
Finally, keep checking these pages to follow along with the project
and our latest findings; your results profile will be automatically
updated to reflect any new information that may come to light based
on the research.
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