Understand DNA Testing

There are three types of DNA testing done in genetic genealogy:

Y-DNA  ♦ mtDNA Autosomal (Family Finder)
Understand DNA Testing for Genealogy
DNA testing may be just the thing to help to break down some of those “brick walls.”  DNA or DeoxyriboNucleic Acid is the molecule sometimes known as the blueprint of life.  It contains the genetic code that exists in each cell of our bodies and is found throughout nature in living things.
♦   All the lab needs is some of your body’s cells to analyze your DNA.  It is easy to get these by scraping the inside of your cheek with a special swab.
♦ The laboratory examines the DNA sample and uses standardized protocols to create a "results" profile for that individual.
♦   A single DNA test is not that useful, but by comparing your results against other individuals' test results, we can determine if you share a common ancestor with a second sample.
♦   DNA testing can confirm that two test participants share a common ancestor. Paper trails (pedigrees) are needed to find which ancestor, when, and where.
♦   DNA testing can also be conclusive in proving that two individuals do not share a common ancestor.

There are three types of DNA testing done in genetic genealogy: 

Y-DNA  ♦ mtDNA Autosomal (Family Finder)


yDNA for Genealogy

  • Each man gets his yDNA from his father, who got it from his father…all the way back.
  • The yDNA test is used for testing males only (males have one x and one y chromosome).
  • Because yDNA is passed down from father to son, just as surnames are passed down in western societies, it is pretty easy to visualize - and to track through genealogy.  This is why yDNA projects are organized around surnames.
  • Females cannot take a yDNA test, but they can make use of this test if they can convince a male relative to yDNA test for this surname line (females have two x chromosomes and no y chromosome).
  • A male researching a line that came down to him through a female can arrange to test a male relative to represent her line. (His yDNA came to him through his father's father's...father's line.)
  • More information about yDNA

mtDNA for Genealogy

  • Both Males and Females can take this test
  • Females carry a specific DNA material that is useful in genealogy called the mitochondria, or mtDNA.  This is the material that surrounds the chromosomes.
  • The mtDNA is passed from a mother to her children, essentially unchanged.  Both males and females inherit mtDNA from their mother, but only females can pass it on.  (If there were no changes, each person would have exactly the same mtDNA as "Eve" and with each other.)
  • This test is only useful in testing the participant's mother's mother's .... mother's line.
  • As this line changes names every generation, it is relatively difficult to track more than a few generations through genealogy.
  • All people who share the same "common ancestor" will carry essentially the same mtDNA and receive tests results that are also essentially the same.

Family Finder-- atDNA (autosomal DNA)

  • Both males and females carry autosomal DNA, which is inherited from both your parents.
  • Autosomal DNA is found on a non-sex chromosome.  Humans have 22 pairs of autosomal chromosomes and a pair of sex chromosomes (X and Y). 
  • Linked blocks of DNA across the 22 autosomal chromosomes are matched between two people.  The degree of matching yields evidence for the relationship.
  • If two people share identical segments of DNA, they may share a recent ancestor.
  • The Family Finder test adds to the information provided by Y-chromosome DNA and mitochondrial DNA (mtDNA) tests. It allows you to trace your other lineages such as your father's mother's father and your mother's father's mother.
  • The Family Finder program determines relationships for up to five generations, but is not as useful in tracing a single surname line.
  • To find the genealogical connection with your match, you need to consult traditional genealogy records. These are birth, marriage, and death records. They also include documents like the census.
  • More information about atDNA (Family Finder). 

Genetic Genealogy helps you uncover your roots! 

  Here are the benefits of DNA testing for the genealogist:

  • Confirm or eliminate relationships.
  • Focuses research to related families.
  • Directs research into a geographic area.
  • Directs research into a specific timeframe.
  • Establishes country or region of origin.
  • Confirms variant surnames are family.
  • Identifies pre-surname migration.
  • Strengthens weak paper trails.
  • Avoids pursuing false connections.
More information on DNA Testing:
WorldFamilies.net DNA the SMART WAY