about Molecular Genealogy
and Osmond DNA Relationships
information published by the
Sorenson Molecular Genealogy Foundation, DNA.Ancestry.Com.,
and other reliable sources.
Analyzing DNA can allow people to find their cousins who may be connected
across generations and around the world. This endeavor is sometimes called
Molecular Genealogy. Here is some basic information about Molecular Genealogy:
and DNA: DNA is found in every cell in your body except red blood
cells. In the center of each cell is a membrane called a nucleus. A nucleus
contains chromosomes, and chromosomes are made up of long strands of DNA
which contain all the body's genes. (Genes are the functional units of
DNA.) Humans have a total of 46 chromosomes, which are grouped into pairs.
Each of the 23 pair consists of one chromosome from our mother and one
from our father. In females the 23rd chromosome pair consists of two X-chromosomes.
Males, however, have an X-chromosome and a Y-chromosome. Therefore, it
is the Y-chromosome that determines male gender.
male Y-chromosome is one of the most useful chromosomes in genealogical
studies, because it has the unique property of being passed virtually
unchanged from generation to generation. This means that a man and all
his sons will have the same (or similar) Y-chromosome, and that males
with a common paternal ancestor have similar Y-DNA.
DNA can also be found in the mitochondria of the cell, which is responsible
for producing energy to perform all cellular functions. The mitochondrial
DNA-called mtDNA--follows the direct maternal line. Women pass their mtDNA
to all of their children, but then only their daughters will pass it on
to the next generation. This makes mtDNA useful for tracing one's direct
contains 59 million bits of information, each of which is encoded by a
"base pair." Looking at all of these base pairs is impractical,
so geneticists have identified a number of specific chromosome locations
that can be used for analysis and comparison. These unique locations are
called "markers". In some ways, DNA marker values are like telephone
numbers, and because telephone numbers may appear in different cities
but belong to unrelated people, it is advantageous for scientists to test
many different DNA markers to avoid possible ambiguity. Generally, the
more markers tested, the easier it is to distinguish individuals and family
tree branches. Currently, some scientists believe that 36 markers are
a sufficient number of Y-chromosome markers to be tested for most molecular
genealogical research purposes. Also, it has been found that individuals
who share exact genetic DNA marker values also share a common ancestor,
and the closer the match in marker values the more recently one's common
ancestor may have lived. However, because of the extrapolative and statistical
nature of molecular genealogy, it is sometimes difficult to predict how
far in the past common ancestors may have lived without the genealogical
information found in reliable pedigree charts.
DNA tests sometimes suggest that people who once thought they were related
are not so related. Such an unexpected finding of "non-relatedness"
may reflect an adoption, an altered or assumed surname, an illegitimate
birth, or maternal infidelity somewhere in the ancestral line. In addition,
one must keep in mind that the science of molecular genealogy is relatively
young, and there is still much that scientists are learning about human
ancestry and its migrations over time, unusual DNA anomalies, and the
extrapolation of specific ancestral relationships through DNA.
What If Your
DNA Test Does Not Support Your Genealogical Assumptions? Suggestion:
Always remember that "Family is family, whether it is by blood, adoption
or inheritance." If DNA testing does not support your genealogical
assumptions, do not distance yourself from those who have supported and
loved you during your life. Regardless of how you received or acquired
your surname--whether it was by blood, adoption or inheritance--stay close
to those who know and love you, and invest in strengthening family ties
that connect you to those you call and know as "family".
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