DNA & GENEALOGY
For a traditional genealogist constructing family trees:
1. Y-DNA is the most useful (only males have it)
2. mtDNA is sometimes helpful (both sexes have it)
3. Autosomal DNA (at-DNA) and X-DNA. There is now a DNA test that everyone – males and females – can use in their genealogical research. This test looks at close relationships along all ancestral lines and is not restricted to only the paternal (Y-DNA) or maternal (mtDNA) lines. Anyone, regardless of their gender, will be able to match to male and female cousins from any of their family lines in the past five generations. Linked blocks of DNA across the 22 autosomal chromosomes are matched between two people. As with our Y-DNA and mtDNA projects, the database for this test will need to grow. In the beginning you may not have any/many matches. Hopefully many of our Y-DNA and mtDNA participant pioneers will be able to invest in this test and enhance the database. FTDNA's test is called FAMILY FINDER..
Below is a short description of the structure of cells followed by the types of DNA with explanations of their usefulness from the point of view of a traditional genealogist.
YOUR DNA IS IN YOUR CELLS
Each of your cells contains 23 pairs of chromosomes - a total of 46 chromosomes. All contain DNA. One chromosome of each pair comes from your mother and the other from your father. The first 22 pairs are usually referred to as autosomal DNA (at-DNA); the 23rd pair is referred to as the Sex Chromosomes (or Y-DNA and X-DNA). All of these chromosomes are in the nucleus of the cell and are sometimes referred to as chromosomal DNA or nuclear DNA. The region outside the nucleus of the cell contains structures called mitochondria with a different kind of DNA known as mitochondrial DNA (mtDNA). mtDNA is necessary for the energy conversion process in the cell. All of your mtDNA is from your mother.
TYPES OF DNA
Autosomal DNA (at-DNA).
Autosomal DNA is MOST of your DNA. It consists of 22 pairs of chromosomes - all the chromosomes except the sex chromosomes (discussed below). Half of your autosomal DNA is from each of your parents. This DNA is "all mixed up" (recombined). Autosomal DNA is the DNA that (1) can uniquely identify a specific individual, (2) contains almost all of your health/medical information, (3) is used in maternity/paternity tests, and (4) is used for forensic/crime purposes (the CODIS test). Now this DNA can also be used by genetic genealogists (FTDNA's FAMILY FINDER test).
Sex Chromosomes (X-DNA & Y-DNA).
The 23rd pair of chromosomes is referred to as the Sex Chromosomes because they determine the sex of the child. The mother always contributes an X and the father contributes either an X or a Y. If the father contributes an X, the pair is XX, and the child is a female. If the father contributes a Y, the pair is XY and the child is a male.
X Chromosome DNA (X-DNA). Males have one X; females have two. The X chromosome recombines and until recently could not be traced back for genealogical information but now (2009) there some limited possible uses being explored.
Y Chromosome (Y-DNA). Only males have the Y chromosome; this is the chromosome that makes a male a male. Most of the Y-DNA does not recombine and is referred to NRY-DNA (non recombinant Y-DNA). This DNA rarely changes (it mutates slowly) as it is passed down to sons from their father's direct paternal/male line - from their father's father's father's father's father . . . .
Because of this, Y-DNA is useful to genealogists, especially in the cultures in which the surname of the male passes down each generation along with the Y-DNA information. This allows for connections to be made with others who share a common male ancestor. Female family researchers often obtain DNA from a male relative with the family surname (and Y chromosome) in order to further their genealogical research.
The Y-DNA test can NOT uniquely identify a specific individual. The Y-DNA test used by genealogists is NOT a paternity or forensic/crime test and it does not reveal any health/medical information.
Mitochondrial DNA (mtDNA)
Both males and females have mtDNA. mtDNA passes down from the mother's direct maternal/female line. In other words, it traces back through the mother's mother's mother's mother . . . .
mtDNA is more useful for deep ancestry information (anthrogenealogy) than for genealogy. Sometimes useful genealogical connections are made using mtDNA, but this is the exception rather than the rule, because (1) mtDNA mutates very, very slowly, and
(2) in many cultures, the surname of the mtDNA line is not passed on to each generation because females acquire a new surname when they marry.
The basic mtDNA test used by genealogists does NOT uniquely identify a specific individual. This test is not used for maternity tests, nor does it reveal any health/medical information. (The full sequence mtDNA could contain health/medical information.)
Limitations of DNA
DNA testing as a tool for genealogists has become popular but there are limitations to what DNA can tell you. If you are only interested in testing to learn about your ancient ethnic ancestry, it is important to understand that while there is some information about the DNA "haplogroups" (deep ancestry going back thousands of years) of ancient populations, generally speaking there is NO known DNA that is specifically or exclusively associated with various ethnic groups. Furthermore, the DNA testing in this project that can identify ancient heritage only applies to your direct paternal or maternal line. In other words, you may have many ancestors from a certain ethnic group but unless they include your direct paternal or maternal line, the tests in this project can not determine that. (Update 2009: Some new developments involving autosomal DNA are now being explored that might be helpful for other lines.)
The Y-DNA or mtDNA test of a person who is a "full-blooded" Asian, Polynesian, etc., may have DNA results indicating his or her ancient ancestry falls into one of the many ancient "haplogroups" that scientific researchers currently believe are associated with these lines. However, many in Hawaii have a rich and varied ethnic ancestry. Even if most of your DNA came from one ethnic group, the DNA tests in this project can only identify the ancient ancestry of your direct paternal (males only) or direct maternal heritage (males and females). Direct paternal line refers to a male's father's father's father's father, going back long before there were surnames. Direct maternal line refers to your mother's mother's mother's mother, going back long before recorded time. (Update 2009: Some new developments involving autosomal DNA are now being explored that might be helpful for other lines.)
IMPORTANT. For over 200 years now, ethnic groups in Hawaii have mixed extensively. Before testing, please be prepared for the possibility that although your family tradition indicates a certain direct paternal or maternal ethnic ancestry, DNA results could indicate that your maternal or paternal ancestral line is not known to be associated with that ethnicity. This would happen if you had an unknown ancestor in your Y-DNA or mtDNA line who was from another part of the world; this could have occurred recently or many, many generations ago.
Asking More Questions
After you have read this page and the FAQ link at FTDNA, you can contact the project administrator if you have more questions or if you are unsure if this project is the right one for you. To do that, click on the REQUEST TO JOIN THIS GROUP link at the top of the left column. Your questions entered there will go directly to the administrator.
In some cases, the administrator may refer you to one or more other Y-DNA surname or regional projects. For example, there are viable Hispanic and Portuguese regional projects and many Caucasian related projects. Or, if your direct paternal or maternal line is Native Hawaiian, you may be referred to the Hawaiian Ancestry project. The volunteer administrators of both of the Hawaii related projects work together. (Administrators of all FTDNA group projects are volunteers and receive no compensation of any kind from FTDNA.)
After you have read this page and the FAQ link at FTDNA and are ready to order, click on the REQUEST TO JOIN THIS GROUP link at the top of the left column. The information you enter there will go directly to the administrator who will recommend the best test for your interests and your budget and will send you a "join code" link for you use to order the test yourself, at the group rate. (Group administrators are volunteers and receive no kickbacks or other compensation for the orders you place.)