LDW - LegacyDNAweb, version 3.0
Connecting Families through the Science of DNA
Surname Research with DNA
Genealogy has depended on traditional historical tools for helping
researchers prove lineages for hundreds of years. Unfortuantely, for many
families the traditional paper trail is either missing or is unable to decide
between several options as to what is the correct lineage for an individual.
Even with the advent of the Internet and the wealth of databases available
on sites like ancestry.com, rootsweb.com, familysearch.org, etc., too many
researchers are finding that they can only prove their ancestry a few generations
beyond their living relatives.
In the late 1990's, newspaper reports were published about how DNA was used
to validate a family legend that Thomas Jefferson could have fathered some of the children of
of one of his slaves, Sally Hemmings. This not only created an uproar within the Jefferson
family, but it opened up to the whole field of genealogy the possibility that
DNA could be used to help with genealogical studies.
By 2002, a number of firms had been established to provide DNA testing and
analysis services to genealogists. Basically, two types of DNA can be used by
The first to be identified was mitochondrial DNA. This is DNA that is
passed, more or less intact, from a mother to all of her children. Of course,
only her daughters pass this along to following generations. This DNA is reasonably
slow to mutate so it is a usuable way to validate a maternal line of descent. Of course,
if could not determine predict which of many sisters would be the mother as they should
all have the same DNA. This tool is probably used more in anthropological studies than
genealogy, but as a larger database is developing, you can expect more genealogical
use of this tool.
The second, and more popular, tool is Y-Chromosome DNA. This is more popular
because it provides pedigree assurance on the paternal surname. Humans have 23 pairs
of chromosomes. The 23rd pair is different between men and women. Women have two
X-Chromosomes that are created by combining the one X-Chromosome they get from their
father and one of the X-Chromosomes they get
from their mother. In contrast, the 23rd pair that men have is an X and a Y Chromosome.
They get the Y-Chromosome from their father and the X-Chromosome from their mother.
Because the Y-Chromosome is mostly intact from the father, a son's DNA, with the
exception of rare mutations, is a mirror reflection of his father's DNA. Or his father's
father's DNA. In fact, some people have been able to validate a common paternal ancestor
back 600 - 1000 years. The limitation seems to be the availablity of paper trail
The scientists have been able to identify two types of mutations in Y-Chromosomes. SNPs
determine the Y-Haplogroup that a man belongs to. These are relatively slow mutations
caused by one DNA base at a particular location on the DNA molecule getting deleted,
added or changed to another base. This seldom occurs more often than
about once every 3000-5000 years. This means that they provide information on
a man's deep ancestry or anthropology, and there is no data that these reverse. Most of
the commonly documented SNPs happened before 'genealogical time' (last 400-600 years). This
means from a genealogical standpoint that two men can only be in the same family if they have the
The other type of Y-Chromosome mutation is called an STR. An STR comes about when
a particular sequence of DNA bases repeat at a particular location on the DNA molecule.
Sometimes, in the replication process, a mutation will occur that changes the number of
repeats. Some locations mutate faster than others; you can expect that even two brothers
could have differences, and sometimes a mutation will reverse in a subsequent generation.
The locations on the DNA molecule are known as markers and the allele value of a
marker is the count of repetitions of the sequence at that location. The haplotype is the
collection of allele values for a number of markers. Genealogy uses the haplotype for
an individual to determine whether or not there is a family match between two men. Several
tools exist to help estimate how recently two individuals had a common ancestor. Please
note that these techniques can not tell you that two people had a specific common ancestor,
only that a common ancestor exists.
Please review the resources below for details of the various technologies.
In the early days of the use of this technology, people were exicted just to
the results from the DNA analysis. However, quickly, they began to ask what they could
really learn from a string of numbers. The answer was that you needed to have lots of
strings of numbers and you needed to compare them, preferably within either a surname,
or some geographical context, to find patterns.
Surname based projects were the most common approach to to DNA analysis. With
a mixture of results from individuals, the people of a surname could be sorted out
into family groups with different common ancestors.
LegacyDNAweb was created to facilitate this sorting process as it was designed
as a database driven tool that would track the DNA results, be able to assign families,
and provide data on the surname pedigree for each of the members.
Implementation of LegacyDNAweb:
LegacyDNAweb (LDW) was originally implemented to support the Davidson
Surname DNA Study Project which was started in June 2004. The current software is
written in php and uses a MySQL database to manage the results. Beginning with version 3.0,
LDW is able to manage a large number of separate projects running on the same server
using a common code base. Using a common template, all of the content is stored in the
MySQL database so that it can be customized for each project.
LDW is accessible to several audiences. Visitors to the site will be able to review
the posted DNA results and the associated ancestry and be able to contact the person
responsible for the specific DNA result to share research data. A visitor will also have access
resource information about DNA and the Surname Genealogy. A future release is planning
an ancestor search engine. A visitor can sign up for a mailing list for project news.
Each member will have their own web page that summarizes the data on their family and
includes their surname pedigree and DNA results and analysis. The member is considered to be
the person who contributed the DNA sample. Each member may assign a contact person for their
sample. It is quite common for the contact person to be the genealogist who is doing the
research but is not a male Davidson. They may have paid for testing and asked a father,
brother, uncle, cousin, etc. to contribute the sample. The contact person will have
access to a back office where they can manage their contact information and manage the
member's pedigree information.
The project administrators have tools to manage the members of the projects,
including being able to add, update, and remove members from the project. They can
create families and assign members to families. They enter the members DNA results,
color code the marker data, and provide the DNA analysis. They can also add new links to
the resource page and update the text associated with the various pages. The can also create
and distribute broadcast messages to contacts, families, or to everyone.
Each project will have a master administrator who can assign create additional
The site is designed specifically for DNA Surname projects working with
Family Tree DNA (FTDNA).
This means that we use the marker designation and analysis standards in use at FTDNA
however, we can add members who have tested elsewhere. However, they will need to provide us
with data normalized to FTDNA standards.
As of September 2016, we have
4 projects installed and
2 are currently active, and
the others are being populated with initial data. See the link above to review the active
The various DNA project web sites are administered by family researchers who are
donating their time and expertise to help make their project successful for everyone.
Please thank them for donating their valuable time to make the project successful.
If you would like to use LegacyDNAweb to help manage your DNA project,
you have two options. If you do not want to deal with technical issues involved
with having a web site, you can install your project on this web site. The cost is
up to US$100.00 to setup the site and US$50.00 per year to host the data.
It is also possible to install the software on your own server. Licensing details
will depend on your specific implementation expectation.
for details or more information for either option.