We have 23 pairs of chromosomes in each cell. 22 pairs of chromosomes are autosomal (atDNA) and one pair is sex chromosomes. Two X’s for female and one X and one Y for male.
I see a huge swell of interest in autosomal DNA testing, especially since the cost has gone down so much. There is a lot of competition among the various testing companies, which is helping to lower costs. Do your swab or saliva test and boom, a few weeks later you get relatives and ethnic origins presented to you. It is as if there is no effort involved other than doing the test. However, this is not true, as it can require a lot of effort to understand the results fully, especially if you have gaps on your family tree or your tree doesn’t go back far enough to make the connection. Autosomal DNA matching has limitations too (another blog post?).
When DNA became available for testing by the public around the year 2000, it was yDNA (y-chromosome DNA) which was used most ubiquitously. ySTRS (short tandem repeats on the y-chromosome) were used and still are, although the number of ySTRs tested has increased hugely since the early days. Mitochondrial DNA (mtDNA) was also available back then and still is, but it was not until many years later circa 2010, that autosomal DNA testing became available to the public. Only one main stream DNA testing company now does ySTR testing which can now be combined with extensive SNP (single-nucleotide polymorphisms) testing. However, I think that yDNA testing is being pushed into the background by the extensive promotion of autosomal DNA testing..
For men, yDNA used in conjunction with autosomal DNA testing can be very powerful when the yDNA aligns with the autosomal DNA. Finding biological fathers for males can be made easier using both yDNA and autosomal DNA.
yDNA testing is tending to become the pursuit of surname enthusiasts and dedicated researchers. SNP testing and next-generation sequencing (NGS) have become the preserve of those who know of its existence, and who have a historic allegiance to yDNA testing. Having been a voluntary yDNA project administrator for many years, I love the pursuit of yDNA testing. Matching other people at more and more intricate levels is like looking for the Holy Grail and it is exciting as you make new discoveries using tests like the Big Y at Family Tree DNA. The dedicated citizen scientists are hugely important in all of this endeavour.
There seems to be a need to impress the public of the value of yDNA testing in family history research. Of course only men can do this test but women can find men on suitable ancestral lines to contribute their yDNA to the research and provide the DNA for such tests.
In the past, headlines were made using Genghis Khan, Niall of the Nine Hostage and Brian Boru in terms of their supposed yDNA trails to the present day. The diaspora felt the excitement of yDNA testing to see if they too were part of this wave. Some of the associations with well-known male figures, such as the above, have been debunked but there is research which is still ongoing to connect manuscripts, annals and historic documents to certain male lines. Members of clans get tested to see if they match the clan male line , or if indeed that male line can actually be ascertained. Non paternity events (fathers not being who they were thought to be) get shown up in the male line.
So, should we be interested in male lines? I think we should be, as there is plenty to be learned from this research. Likewise, tools for autosomal DNA analysis should be provided by the testing companies to make it possible to get as much out of the test as possible. It is not magic!
Perhaps, with the cost of testing the full genome coming way down, this is the future of genetic testing.