Which DNA Tests
Autosomal
The most popular DNA testing covers the 22 pairs of autosomal chromosomes. In some cases the 23rd pair, i.e. the sex chromsomes are also included. In most cases you will get an "ethnicity report" which will give you an idea of where your distant ancestors came from. Also many of the companies have a DNA database and will compare your DNA with others in their database. Through this you should be able to connect with other relatives and their family tree. Unfortunately relationships beyond 4th cousin can be difficult to track down for your Irish roots as you run in to the problem of a scarcity of Irish birth records.
Y-chromosome
Not so many companies carry out y-chromosome testing, "Family Tree DNA" is one of them. It is most useful for researching the direct male line and surname. It can uncover some interesting stories as you can see in our section Y-chromosome and Father's Ancestral Line.
Mitochondrial DNA
Not many companies carry out this test either, again "Family Tree DNA" is one of them. This is most useful in researching the direct maternal line, see our section Mitochondrial DNA and Mother's Ancestral Line
DNA And Your Irish Roots
• DNA and your Irish Heritage
• DNA, Discovery and Functions
• Types of DNA tests
• DNA testing companies
• Y-chromosome and Father's Ancestral Line
• Mitochondrial DNA and Mother's Ancestral Line
• DNA and Ethnicity