A beginner's guide to DNA genealogy

DNA genealogy, the quickly burgeoning field in the fascinating world of genetics, is largely an unfamiliar one, to both beginners as well as the seasoned genealogical researcher. While it hasn't yet replaced traditional methods commonly used to trace one's family tree, DNA genealogy can be an invaluable tool when used in conjunction with other types of similar research.

DNA, which is short for deoxyribonucleic acid, originates from four chemical bases that come together to form a "rung" or scientifically, a "chemical base pair". These rungs contain roughly three billion pairs that together form a human genome, which is comprised of 35,000 different genes that are carried in the chromosomes passed on by each parent.

Types of DNA Genealogy Tests

There are two basic types of tests that are commonly used for DNA genealogy purposes; the mitochondrial DNA test (mtDNA), which is used for testing maternal lineage, and the Y DNA test, also referred to as the Y-line DNA test, used for testing paternal lineage.

Mitochondrial DNA test: Passed on from mother to child, mitochondrial DNA is located within a cell's cytoplasm, the gelatinous substance that surrounds the cell. Since this particular type of DNA is only passed on by a female, and is one that is changed or altered very slowly, a child's mtDNA is exactly the same as their mother's, which would also be the same as her mother's, and so on. Test results from a mitochondrial DNA test would show if two people shared a maternal ancestor, but, due to the nature of the DNA itself, wouldn't necessarily be able to determine if this person was a close relative, or one who lived several centuries ago.

Y DNA test:. Microscopic chemical markers located on the Y chromosome, which is only passed on by a father to a son, create distinctive patterns known as haplotypes. A haplotype does not show the exact degree of relationship between two people, but it can be used to distinguish one particular lineage from another. The Y DNA test is commonly used by people who share the same surname and are trying to determine if they are in fact related through some common ancestor.

Both types of tests are able to test the genetic lines of two of our eight great-grandparents, the father's paternal grandfather and the mother's maternal grandmother. For determining ancestry stemming from any of the six other great-grandparents, the DNA samples of uncles, aunts, or cousins who are direct descendants from either an all-male or all-female line will be necessary.

Beginning genealogy enthusiasts may want to take note that a woman cannot trace her paternal male lineage without DNA from either a brother or her father since females do not carry the Y chromosome. Likewise, a male does not pass on mtDNA to his offspring, male or female, which only comes from his female parent.

Understanding DNA Genealogy Test Results

The genetic marker numbers that result from either type of test will hold no real significance until they are compared with the numbers from several other people. A match of your DNA with another person's indicates a common relative shared between the two of you, who is known as the MRCA, the most recent common ancestor. Results aren't able to indicate exactly who that common ancestor is, but they may be beneficial for narrowing down the choices to a specific generation.

Some of the benefits DNA genealogy tests provide include:

Providing clues about one's ethnic origin

Determining whether or not two people descend from the same ancestor

Validating, or invalidating, existing family history research

Determining if two people who have the same surname are related

Determining if two people are related to each other

DNA Genealogy Studies

A DNA Surname Study

Many novice genealogists are learning how to organize what is known as a DNA surname study, a project which uses DNA genealogy test results to analyze emerging genetic patterns. Some studies are used to track one single surname, or spelling variations and foreign versions related to the same name, while others focus on a specific geographic region as opposed to a global study.

While the exact methods of managing and conducting a DNA surname study are purely matters of personal preference, there are a few basic steps that will produce the best results.

1. Create an end goal: First, it's helpful to have a set goal in mind for the study before beginning. The end goal may be centralized in nature, attempting to identify people from specific areas of the world, or it could be rather broad and used to determine how people with a particular surname may be related.

2. Choose a DNA testing service: After you've decided on a specific goal, decide on a laboratory that provides DNA testing services, many of which will offer guidance for starting and organizing a surname study. Also, some companies offer discounts for groups with a large number of participants.

3. Gather participants: In addition to direct contacts through family members, the internet provides an excellent medium to locate others with the same surname who may be interested in joining in a study. Creating your own web site or sending out mailings are also effective ways of recruiting people to join in the surname study. The subject of DNA and genetics can be a very personal matter for some, so be well informed and prepared to answer questions and concerns from prospective participants.

4. Manage the study: Besides keeping all information efficiently organized and updated, maintaining the participant's privacy and informing them of any discoveries or results are two other important aspects of managing a DNA surname study.

The Genographic Project

Launched in 2005, the Genographic Project is a five year study led by IBM and National Geographic that intends to map mankind's journey throughout the ages. Previous and similar DNA studies have already suggested to researchers that all humans descended from African people who lived as long as 60,000 years ago.

The Genographic Project intends to follow the migratory history of man by using DNA samples that are donated from volunteer participants living all over the globe. Attempting to become the largest DNA survey ever conducted, the project aims to collect at least 100,000 samples, and then trace how various parts of the world became populated over the millennia.

Home DNA Test Kits

Only recently have home DNA test kits been affordable for the average person to use independently. These tests usually cost an average of $100 to $400 USD per kit, and will generally take four to eight weeks for the results to arrive by mail. Either a special mouthwash or a swab to wipe cells from the inside of the cheek are used to collect DNA samples from the mouth and then returned to the lab for testing. The results will be a series of numbers used to represent the chemical markers found within your DNA.

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