Why DNA?

Nov 30th, 2013 | By | Category: Joyce DNA Research

I have had a number of people message me requesting information on DNA testing and I thought it was probably timely to give some information on what it can reveal here.  I do not pretend to be an expert, I am an enthusiastic amateur who has learnt a lot and who has identified distant family members because of the tests I have done.    As I said in my introductory message to everyone I am also the administrator of the Joyce DNA Project at Family Tree DNA and I am actively recruiting people for that Project.

Why?  It’s actually pretty simple.  I have a deep curiosity about my family origins and the paper trail for most of us peters out in the early 1800’s.    I had the pleasure of going to a talk by History Channel presenter Neil Oliver last night and much of what he said resonated with me.  It is about connecting with people, understanding where they came from, what conditions they lived under and why they may have moved.    Finding my DNA cousins helps to fill in some of the gaps in my own tree.

So what can it show us?    Imagine that you hold out your arms in the form of a V.   For males your left arm marks your YDNA which is inherited Father to Son.   Over time that DNA mutates and changes so a brother may pass on a marker to his sons that his sibling does not have.   Those markers are being discovered at an almost exponential rate at the moment and if you share a marker with someone else then you share a common ancestor.

There are two types of tests there – the first compares repeats of code on known markers of the chromosome and there are various levels of tests in terms of number of markers tested – 12, 25, 37, 67 and 111 – the more markers you test for, the greater and the more markers of the exact value that you share, the closer in time your shared ancestor becomes.  This is called STR testing, stands for short tandem repeats.

The second type of test is for one is SNP testing which looks for specific mutations – if you share a mutation then you share an ancestor.  There have been huge advances in this area recently and that holds the best hope for bridging the written record with pre-history and for linking people together.

Both types of tests are important not only for identifying a common ancestor, even though we may never know the name of the person or exactly where he lived, but they are also important in identifying related family names and will assistant in narrowing down the geographic area our common ancestors came from.

Let’s take an example of the Joyce name – if we are indeed of Welsh Norman in Origin and arrived in Ireland in the 1200’s then we won’t carry the marker that many Irish men have that indicate descent from Niall of the Nine Hostages which is a marker called M222.  I have tested negative for that marker which is one possible pointer to a later Irish origin for my own family.

You can read more of Niall here – http://en.wikipedia.org/wiki/Niall_of_the_Nine_Hostages

So I would like more male Joyces to test to see how many clusters we may have and in the Joyce DNA Project at the moment there are some 20 males which give us some clues but not enough to give us statistical significance.  How many more of us do not carry the Niall marker?

Back to our V shaped arms for a moment – the other arm represents our autosomal DNA; i.e. that DNA which both males and females inherit from our mother’s mother’s line.   That can provide us with further deep ancestry information but in terms of linking back to a name is difficult because we don’t generally have our female line name passed on.   I carry within me through my Mum evidence that my ancestors on that line were Australian Aboriginal and can therefore state that on that line my ancestors have been in Australia for 50,000 years.

The space between the two arms of the V is the autosomal DNA which we inherit across our other 22 chromosomes from both our mother and father who got it from their mum and dad before them.  Each generation we go back we double the number of ancestors who contribute their DNA to us and there are some statistical thresholds used to match with other people that also indicate shared ancestry.  The difficulty is that we do not necessarily know which line we match people on unless other known members of your family also test so that you can triangulate and work out the exact line.

Some members of the Joyce Family DNA Project have done precisely that and know exactly what part of what chromosome they have inherited from their Joyce ancestor and have therefore been able to sort their matches and can with a fair degree of certainty say that people who match that place on that chromosome must also be Joyce descendants even if they don’t have a paper trail to confirm it.

Family Tree DNA have a Holiday Sale on at the moment and there are different entry level packages available.   For our female Joyces may I suggest that you order the Family Finder test which is currently on sale for $US99.   That will give you the autosomal results and if you are like me you will find that you will match immediately with 500 – 1000 other people and then the fun will start with trying to work out what line the match is on.

For all of you male Joyces I would suggest the Family Finder plus YDNA 67 at $US288 or Family Finder plus YDNA 37 at $US218.   Selfishly the more markers the better from the Project point of view.   If you want to test for SNP’s (like the Niall marker) then the Comprehensive Genome is $US496.

Four Joyce DNA Project members have so far ordered this one.  It is a totally new test and there are high expectations of the discovery of many more SNPs which will help further define the genetic tree and where we fit.   We should be able to further clarify whether as Joyces we all share the same markers or whether we have a number of different branches who just happen to share a name.

Here are some links to some really good articles but if anyone has any more questions please post a comment here and I’ll do my best to answer them.

http://dna-explained.com/2013/09/15/why-dna-test/

http://dna-explained.com/2012/08/10/to-snp-or-not-to-snp/

Leave a Comment

You must be logged in to post a comment.

Skip to toolbar