What follows is an extracted from the Family Tree DNA's "Facts & Genes" Newsletter (11 Sept. 2003, Vol. 2, Issue 8).

Understanding Your Results: mtDNA
=================================

The mtDNA test provides information about your direct very distant
maternal Line ancestor.  Therefore, the mtDNA test is known as an
anthropology test, since the results relate to the very distant past. 
The mtDNA test may also be used for genealogical purposes.

The mtDNA test can be taken by males and females.  Both males and
females inherit mtDNA from their mothers, though only females pass on mtDNA. 
The mtDNA you inherit from your mother, came from her mother, who inherited
the mtDNA from her mother, and back in time.  Your mtDNA has been
passed down for thousands of years, all the way from one of the original
females. These original females are called Clan mothers, or nicknamed "Daughters
of Eve".

Over 20 of these "Daughters of Eve" have been identified for the world,
of which 7 of these "daughters" are largely confined to Europe.  As people
are tested in the more remote areas of the world, more "Daughters of
Eve" may be identified.  Your "Daughter of Eve" is represented by a letter,
which the scientists have established, and call a Haplogroup.  For
example, your ancestral "Daughter of Eve" could be H, X, T, K, and so
forth.

A result of A, B, C, D and sometimes X shows that your direct maternal
Line has native American ancestry.  A result of H, I, J, K, T, U, V, X
shows that your direct maternal Line has European Ancestry.
The Haplogroup X is found in Europe and Asia, and is believed to have
migrated to the Americas about 15,000 years ago, making up a small
component of the native American population.

For Europe, the "daughters" can be loosely broken down into Southern
Europe and northern Europe:

Southern Europe:  J, K
Northern Europe:  H, T, U, V, X

For Africa, the Haplogroup or "daughters" is L, L1, L2 and L3.

For Asia, the "daughters" are:  A, B, C, D, F, G

The first humans originated in Africa, about 130 thousand years ago.
Various migrations out of Africa populated different areas of the
world. The northern Europeans and Southern Europeans migrated out of Africa
about 39-51 thousand years ago.  Asia was populated by a migration out of
Africa about 56-73 thousand years ago.

From Asia, there were possibly 3 different migrations to the Americas
by crossing the Bering Strait.  The first migration into the Americas was
probably about 26 thousand years ago, the second was about 12-15
thousand years ago, and the third was about 7-9 thousand years ago.
The data also demonstrates a possible 4th migration about 15 thousand
years ago. Some researchers have suggested that this group could be
related to the Scandinavian Vikings, and may have crossed the Atlantic
and mixed with Native Americans that crossed the Bering Strait(Haplogroup
X).

Occasionally, an ancient human has been discovered and their mtDNA
tested, such as the Ice Man.  The 5000 year old Ice Man belongs to Haplogroup
K. The Cheddar Man belongs to Haplogroup U.

The mtDNA test, besides telling you about your very distant direct
female ancestor, can also be used to confirm genealogical relationships.  If
two persons are linked by a common female ancestor, then their results from
the mtDNA test will match.  The two persons could be either male or
female, as long as the male's mother belongs to the direct female line
being tested.

mtDNA testing may confirm genealogical relationships, and therefore
potentially useful in solving genealogical research problems involving
female lines.  For example, perhaps your family tree has a situation
where a male ancestor had two wives, and you are not certain who the mother
was of two of the daughters.  (The two wives were not sisters from the same
mother.  If the two wives were sisters of the same mother, they would
have the same mtDNA, so this example would not work.)  To determine which
wife was the mother of which child, you would trace the direct female line
from the two children, to find a descendent today to test.  The descendent
today could be male or female, as long as the male's mother was in the
direct line.  You would also want to trace the descendents of one
daughter whom the mother is clearly identified as wife 1 or wife 2.  The results
of the mtDNA test for these three participants would show which wife was
the mother of which daughter.

In another example, we have a situation where a female was shipped off
to Australia as part of a government emigration program for those in
poverty in Ireland in the early 1800's.  The baptismal record of the female can
not be found, due to the destruction of many of the parish registers in
the civil war in Ireland in 1922.  There are 3 possible families in the
area where the girl was last known to reside in Ireland.

mtDNA testing could be used to determine which family was the girls
ancestors.  For each of the families, a direct maternal line would need
to be traced to find a descendent today, and tested.  The results from the
three participants would be compared to the result for a descendent of
the girl.  Which ever result the descendent of the girl matches, would be
the ancestral family.  Further research may now be possible with the family
identified.

The reasons to have an mtDNA test vary from personal knowledge about
your direct maternal female ancestors, to applications to solve genealogical
problems.  Some customers test mtDNA for all the core members of their
family tree.  Usually this application of mtDNA testing is to gain
knowledge about the direct maternal line of the core ancestors, as well
as to confirm the genealogical research.

mtDNA changes at a much slower rate than Y DNA.  There are two mtDNA
tests available:

Maternal Match
mtDNAPlus

The Maternal Match tests one region of mtDNA, and the mtDNAPlus tests
two regions.  These regions are called HVR-1 and HVR-2, and are known as HV
Segment or HV Region.  The abbreviations for these two regions are also
called HVS-1 or HVS-2.  The scientists use both the terms HV Segment
and HV Region, as well as the associated abbreviations.

The Maternal Match test only tests HVR-1, and the mtDNAPlus tests both
HVR-1 and HVR-2. Family Tree DNA's HVR-1 test includes 540 base pairs,
and the HVR-2 includes 510 base pairs. It is highly recommended that the
mtDNAPlus test be ordered by those persons interested in a genealogical
application, or for matching.   mtDNA has a very slow mutation rate. 
The chart below shows the time frame of the common ancestor for a random
match.



Test              Time frame of common ancestor for a match
=============     ===========================================
Maternal Match     50% of the time, 52 generations or less
mtDNAPlus          50% of the time, 32 generations or less




These time frames are for random matches.  When you are utilizing mtDNA
testing for genealogical purposes, you have identified the ancestors or
potential ancestors, so the time frames shown above are not relevant.

mtDNA test results show the Haplogroup, and the mutations compared to
the standard, which is called the Cambridge Reference Sequence (CRS).  The
CRS is simply the first mtDNA sequenced, so all results are presented as
the mutations compared to this standard.

Since mtDNA mutates, or changes, very slowly, the Matching selection at
familytreedna.com only provides exact matches, since partial matches
with HVR-1 are not genealogically relevant.

For mtDNA test takers, your Personal Pages at familytreedna.com will
show three selections:

mtDNA Matches
mtDNA Search
mtDNA Results

The mtDNA Matches selection shows those to whom you are an exact match,
for both HVR-1 and HVR-2.  The HVR-1 matches are known as a low
resolution match, and the HVR-2 matches are known as a high resolution match.  For
genealogical purposes, only a HVR-1 + HVR-2 match should be considered,
unless your mtDNA sequence is quite rare.

The mtDNA Search selection shows the ethnic origin for those whom you
match, from the Family Tree DNA customers, as well as other proprietary
databases.

The selection mtDNA Results, shows your results for the mtDNA test.

A mtDNA test can provide interesting information about your direct
female ancestor, as well as be used for genealogical research purposes.  Some
customers prefer to have a mtDNA result for each of their core
ancestors in their family tree.