Paternal Line Research
Have you ever looked into the mirror and wondered, "Where did I
get that hair?" yet at the same time realized that the older you
get the more you look like your mother or father? The DNA that a
son receives from father is not only influential in determining
eye color, hair style, and height; but also in identifying who
the father was. More specifically Paternal Line Research is
defining who we are by helping to determine where we came from.
Paternal Line Research uses Y chromosome testing to trace
the paternal line. Throughout time, Y-chromosome tests are only
available for males, because the Y-chromosome passed only down
the paternal line from father to son. There are tiny chemical
markers on the Y-chromosome that create a unique pattern. This
pattern is used to distinguish male lineages from each other.
This type of testing is often used to determine if two
individuals who have the same surname share a common ancestor.
Furthermore, this test is often used to provide additional also
details in paternity cases where the alleged father is not
present for testing.
The Y-chromosome is passed from father to son and has the
property of remaining unchanged for several generations.
Y-chromosome mutations generally occur once every 500
generations. Because of this consistency in the Y-DNA, it is
very accurate in assessing relatedness and even more accurate in
assessing un-relatedness (Paternal 2005). Additional information
that can be gathered from Paternal Line Research is the
approximation of a common ancestor or most recent common
ancestor (MRCA) and the most likely estimate (MLE) to a common
ancestor--an estimate of when the most recent common ancestor
between two relatives lived (presented in generations).
The field of Paternal Line Research has rapidly improved in
recent years due to the fact that Y-chromosome analysis has
improved. New markers have been discovered and population groups
are being characterized (Kayser et al. 2004). Various tests have
been conducted as well as validation studies. Both have
demonstrated that Y chromosome testing is in
fact reliable (Butler 2005). Many different examples abound that
indicate the value that Paternal Line Research testing has in
forensic DNA casework. In addition, internet-accessible
databases house thousands of Y-DNA haplotypes making Paternal
Line Research an increasingly popular and accessible field.
The Easy Y-Match and Exact Y-Match search engines of the
Relative Genetics' database allows searches of Y-chromosome
paternal line test results. These two search functions will
allow clients to identify other individuals with whom they may
have a close genealogical connection. Web site visitors may also
search for possible relatives using a basic surname search. The
recently improved flexibility of the Web site allows individuals
to create new projects, participate as members in multiple
projects, and accept project members who have been tested by
organizations other than Relative Genetics. In addition, members
of Group Projects will find that the color coding and sorting
features of the group data table makes it easy to quickly
identify relatives within their group. Web site visitors are
also granted convenient, effective access to the Sorenson
Molecular Genealogy Foundation database.
Paternal Line Research is still largely untapped and it will be
very interesting to see what the future holds. For example, DNA
casework currently has yet to accept Y chromosome testing as a
valid standard and instead still sees it as a specialized
technique only to be used in unique situations (Butler 2005).
Databases will need to expand in size and power in order to
strengthen the statistical information regarding a match. In
addition, the many different markers that are available need to
be further characterized to better define where they fit in
analyzing haplotypes and the strength of matches. At any rate,
Paternal Line Research has great potential in addition to the
great success that it has already produced.
Sources
Butler J. (2005) Forensic DNA Typing; Biology, Technology, and
Genetics of STR Markers, 74, 231-232.
Kayser, M., Kittler, R., Erler, A., Hedman, M., Lee, A.C.,
Mohyuddin, A., Mehdi, S.Q., Rosser, Z., Stoneking, M., Jobling,
M.A., Sajantila, A. and Tyler-Smith, C. (2004) American Journal
of Human Genetics, 74, 1183-1197.
Paternal Lineage. (2005). DNA Diagnostics Center.
http://www.dnacenter.com/dna-testing/paternal-lineage.html.