Welcome to Haplogroup W!
Haplogroup W Origins and Subgroups
Haplogroup W occurs primarily in South Asia, the Near East, Central Asia, and Europe, with an average of only 1 to 2% of the population being of this group. That said, as indicated on the map, there are clearly peak concentrations of W's (5% to 10% of the population) in Azerbaijan, Georgia, Tajikistan, Pakistan, Northwest India, Kurdistan and Northwest Iran, Hungary, and Finland. However these general figures disguise important differences between the subgroups.
The first migration of modern humans beyond Africa and the Arabian peninsula began around 60,000 years ago. Among these were ancestors of the the M and N haplogroups, descended from L3. These first Eurasian descendants of genetic Eve seem to have been boat-building fisherman, and are believed to have expanded quickly along the Indian Ocean coastline. After a quick initial expansion along the coast, all the way to Australia, there was a slower conquest of the interior of Asia.
The first member of what is referred to as the W haplogroup, whom we refer to as Wilma, was born between 15,000 and 19,000 years ago, probably in what is now northwest India or northern Pakistan. This was at the end of a period of cold known as the Last Glacial Maximum. Migration of people outside of the W homeland was blocked to the north by extremely arid arctic deserts. As the climate began warming, between 19,000 and 11,000 years ago, nomadic hunters expanded back into these areas, which were becoming grasslands. The existing modern W subgroups emerged in the area between the Caspian and Aral Seas during this period.
As the population expanded, both in numbers and area, the new Haplogroup W subgroups developed. Around 15,000 years ago a W woman had a mutation at position 7864 in the coding region, the first W1. Another W womand had a 194 mutation in HVR2. From here would be descended the W3, W4, W5, W6, and W7 subgroups. Ten other subgroups have been identified but not given official designations yet.
How to Read These Phylogenetic Trees
W1 is defined by the 7864 mutation. The Finnish-Nordic branches of this subgroup account for a large portion of northern European W's. W1 began differentiating into subgroups around 15,000 years ago. The descendant lineages went both into Europe and Scandinavia via Russia, and the Middle East via Iran, but each lineage with very diffferent routes and timings.
W3, the oldest subgroup, appeared around 14,000 years and spread later via the horse culture of the steppes into Europe and India. They are found today in both Europe and South Asia.
W4 is defined by the striking HVR2 motif 143-194-196. It appeared in the central Asian steppes around 9,000 years ago. One lineage migrated via Scandinavia into Britain and Ireland. Others are found in central and western Europe, Anatolia, Russia, and India.
W5 is a uniquely European group, although it originated 10,000 years ago, probably in the Russian steppes. Its subgroups differentiated during the period of the Corded Ware culture in Central Europe, beginning 5,000 years ago. Later migrations of Celts, Saxons, and Vikings carried the type to the British Isles.
W6 is identified by the 16192 16223 16292 16325 16519 motif. It originated in Central Asia around 13,000 years ago. The structure of its descent tree and the wide distribution of its members indicate that it spread throughout the Middle East and Europe in the same period and along the same routes as the first agriculturalists.
W7 is identified by the 185 HVR2 mutation and is found at present among those of Armenian descent.
There are at present ten W subgroups that have not yet received an official designation, and many subgroups. Such designations are not usually allocated until at least two full genome results establishing the subgroup are submitted to Genbank.
What Does It All Mean?
Your mtdna result is unique among all other types of dna results because it alone shows you an unbroken lineage going back thousands of years all the way back to genetic 'Eve'. This is your matrilineal line - your mother's mother's mother's mother's mother's....mother. Full genome results, such as 23andme or Family Finder, can help you locate relatives no farther back than five generations or so due to recombination. If you're a man, Y-dna results trace your patrilineal line back to genetic 'Adam', but for now without the level of certainty in recent times that mtdna provides. Only your mtdna result gives both men and women a complete insight into one lineage of their family and allows remote common ancestors to be identified.
Combining the information on your place on the tree with the current Old World geographic locations of your relations and rough dating for each branch of the tree via the genetic clock, allows the origins and migrations of your ancestors to be determined.
There is a lot of confusion because these each of these migrations are of a single lineage, leading from Wilma, around 17,000 years ago, to you today. Each of these lineages have their own history. W's or W1's or W3's or whatever did not belong to a particular clan or tribe. Rather a particular lineage traces the migrations of a particular woman's descendants, who were part of various tribes, cultures, or peoples over the millenia. This means charts showing the 'migrations of a haplogroup', or showing the percentage of a haplogroup in a particular population, can be misleading because they are combining information on the locations and migrations of various individual lineages, which can have very different routes and histories.
It also has to be understood that the lineages that exist today are only a tiny fraction of all of those that ever existed. Genetic 'Eve' was not the only woman alive 180,000 years ago. There were tens of thousands of others, including not only genetically modern humans, but also Neanderthals, Denisovans, and other archaic humans. We now know that they interbred with modern humans, and are part of our DNA ancestry. But they have left no existing mitochondrial lineages.
You know yourself of male or female lines in your own family that have come to an end when a particular relative has no surviving children. The situation was even more dire in prehistory.
Think about it: for thousands of years, the earth's human population was relatively stable. That meant that each woman, on average, had two surviving children, of which, on average, one was a girl who could pass on her mitochondrial DNA to a new generation. However individual women may have had no children, or no girls, that survived to have children in turn. Those matrilineal lineages were lost.
Now if there are thousands of women with the same mitochondrial DNA sequence, then things will average out and at least some women will survive in each generation to pass on the lineage. But prior to the advent of agriculture, many humans lived in small nomadic groups, and the chances of losing a particular lineage were much greater.
Being a hunter-gatherer nomad on foot meant that a woman could not have more than one babe-in-arms at a time. The interval between births was delayed by nursing the children for a longer interval than in later times; and use of abortion or infanticide. As a result, it is estimated that in Paleolithic times the average woman gave birth every 27 months.
Every birth carried a 10% chance of the death of the mother in childbirth. The result was that the average woman had 4.7 live births during a 13-year reproductive span (from age 16 to age 29). Half of these were girls; but with 50% infant mortality, deaths prior to reproductive age, and women who could not conceive, only enough children survived to replace their parents.
When a new mutation occurred in a paleolithic woman, there was therefore only a very small chance it would be passed on to enough descendants to ensure that it would survive in the population. As we go back in time, fewer and fewer of the lineages and haplogroups that ever existed survive today. So our tree of descendants from Wilma is woefully incomplete. It had many branches and twigs that did not survive to present times and we cannot know about (except as more ancient DNA results become available).
Although a migration route can be guessed at, the timing in many cases is ambiguous because the genetic clock is very rough indeed. In a full genome, there is only one new mutation in a lineage every millenium or so, on the average. But this is an average - there can be many thousands of years between mutations on some lineages. In fact, in the 18,000 years since Wilma, there are between one and 16 mutations depending on the lineage, with the average being five. Confident dating of a lineage requires a large number of descendants in the tree, but currently there may be so few that dating is very uncertain.
One conclusion from the tree analysis and the ancient DNA evidence is that haplogroup W only arrived in Europe after 5000 BC, among the peoples who brought agriculture and pastoralism to the continent. So while it may be concluded that a given lineage entered central Europe from the Eurasian steppes, it may not be possible to determine if it arrived with the pastoralists that introduced the horse there around 4000 BC; or by later migrations by the Celts, Germans, Slavs, or Magyars.
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