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Discovering
your GeoFather™ using the Y chromosome
The Y chromosome provides a very powerful tool for
discovering ancestral male lineages. This is because,
unlike other chromosomes, the major part of its DNA
does not get changed when it is passed down from father
to son.
Occasionally, however, when a Y chromosome is passed
on, its genetic code does undergo a very small alteration.
The vast majority of these alterations are completely
harmless and so are eventually passed on to succeeding
generations. Over time, further small alterations
occur. In this way, separate male lineages become
increasingly different from each other.
Because it is only males that inherit a Y chromosome,
analysis based on this genetic material can only be
performed on male DNA. However, women may obtain this
information by using a sample from a male relative
such as a brother or father.
Building a global family
tree
By comparing two men’s Y chromosomes, it is possible
to judge how closely they are related. If their genetic
codes are very similar, we can say that they share
a common male ancestor in the recent past. The more
differences that have accumulated in their genetic
codes, the more generations have passed since their
last common ancestor.
Scientists have used this basic principle to compare
the DNA from thousands of men living all across the
planet. They have used their findings to construct
a global family tree of male ancestors.
The journeys that shaped
history
This male family tree is rooted some 100,000 years
ago, at a time when the ancestors of all modern humans
were living in Africa. As some of these early groups
of humans took their first tentative steps out of
our ancient homeland, their journeys led them in different
directions and their family lines gradually began
to diverge. It is these different lineages that form
the separate branches of the global family tree.
GeoGene has divided the male family tree into 17 unique
accounts tracing the most important of these journeys
– the ones that would define the course of subsequent
human history. The account we send you will reveal
the route your own paternal ancestors took as they
left Africa, explaining how and when your ancestors
arrived at the part of the world in which their genetic
inheritance is most visible today. You might, for
example, learn that you inherited your Y chromosome
from one of a number of groups of hunter-gatherers
who arrived in Europe around the time of the Great
Ice Age. Or you might discover that you are descended
from a group of Neolithic farmers who journeyed into
Europe from the Near East after the Ice Age had ended,
bringing with them agricultural knowledge that would
change our way of life forever. Or perhaps you are
descended from another ancestral lineage.
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