Dowling DNA - by Brian Thomas Dowling (1955-)

I have had my DNA tested with the three main tests: 'Y-DNA', 'mt-DNA' and 'at-DNA'.

Test What Tested Result for Haplogroup (group who share a common ancestor) Diagram or notes
Y-DNA tests the male genome. 

Father's father's father, etc. and so on back until genealogical Adam! (nothing to do with the Bible).

This is a very accurate test of your origin via the male line. The Y test can be extended with additional and more expensive tests to give much finer results which, in the Dowling context, can give a link to the Seven Septs of Laois.
The cell's nucleus has 23 chromosomes.  This tests just one half of only the 23rd chromosome used to determine gender.  Only males have this DNA tucked away in the nucleus of a cell.  I got this  from my father and it has hardly changed for many generations. (in a male this pair of chromosomes is X & Y, in a female it is X & X, so women cannot be tested for this Y-DNA). R-FGC28340

(a subclade of R-M269, which is a subclade of R1b)

About 25,000 years ago this group inhabited Western Europe. While matches occur all over the world those matches consistently have a connection to Ireland.
Y Test Chart  R1b Migration Map
mt-DNA tests the female genome.

Mother's mother's mother, etc. and so on back to one of the genealogical Eve's (nothing to do with the Bible).

This is a very accurate test of your origin via the female line. This test can be made with partial or, at greater cost, 'full' solution.
Males and females all have this, and mine comes from my mother.  Mitochondria is found in the material surrounding the cell's nucleus and has lots of detail.    K1a11 Mitochondria Test Chart  K Migration Map
at-DNA tests autosomes.
Also called the Autosomal test.  FamilyTreeDNA call it their 'Family Finder' test.  Many other companies, who only do one type of test, are a little misleading by only referring to it as their "DNA test" suggesting it is the only test when it is only one type of test.

Generally has part of DNA for both parents, both sets of grandparents, great-grand parents, and less-accurately, great-great grandparents.

This test can include a test for some 'X' information but this tricky to interpret right now.

Some of the matches with previous testers may give an indcation of origins of your test, for example it may say you are .1% Finnish or 20% French or some other mix. This is of interest but in no way as accurate as 'Y' or 'mt'. Some company results may make a poor guess at haplogroup.
This is a test of 22 of the 23 pairs of chromosomes called autosomes. 

Males and females have this but its all a bit muddled up as to which bit comes from the mother or father.  As a result it is not so good for tracking a male or female line.  However, it is really good for recent ancestors to 4 or 5 generations back on both sides. 

Although not so accurate for deep ancestry (use 'Y' and 'mt' for that), the 'at' test is excellent because it is cheaper than the others and, therefore, there are a lot more people who have had the test (matches). 
100% European

made up of:

71% British Isles

19% West & Central Europe

10% East Europe

with a trace in South America
Ausomal Test Chart 

no map for 'at'  

The Family Tree Guide to DNA Testing and Genetic Genealogy by Blaine T Bettinger - Family Tree Books - ISBN-13: 978-1-4403-4532-6

Genetic Genealogy - The Basics and Beyond by Emily D Aulicino - AuthorHouse - ISBN 978-1-4918-4090-051995


NOTE: All DNA results relate to matches. So, if you get yourself tested, you will improve the accuracy and certainty of results in future.

Authors DNA results tested by FamilyTreeDNA. This includes 'Y' (Y-111 & Big Y-500), 'mt'(Full) and 'at' (they call it Family Finder). The 'at' test has been circulated though MyHeritage and GedMatch.

(note: I am not on Ancestry.com as their current test, an 'at' type, failed with my sample. Years ago Ancestry did successfully do my Y-46 test but then Ancestry took a policy decision to dump this test-matching in 2014 (as they did for all other test takers) so that is not available on Ancestry either).