If you’re already using a specific geneology program, use their DNA test. I used My Heritage while I was using Ancestry for my family tree. I got called by a high pressure salesman to sign up for the My Heritage geneology program. (I had uploaded my gedcom to the My Heritage site.) I told him that I couldn’t afford two geneology sites. The guy was snotty and condescending. We figure we just wasted our money with My Heritage and will do the Ancestry DNA as soon as we can afford it.
The 100,000 Genomes Project is an NHS initiative, run by Genomics England, and is the largest national genome sequencing project in the world. On entering, patients have their entire genome, of more than 3bn base pairs, sequenced. This is different from commercially available genetic testing kits, such as those from 23andMe, which only look at very small stretches of DNA in a process called genotyping. The hope of the NHS is that having so much genetic information, from so many different people, will allow “groundbreaking discoveries about how diseases work, who could be susceptible to them, how we can treat them, and what treatments might work”.
Whether it’s an autosomal test, a Y-DNA test or an mtDNA test, virtually all providers use the same science. Some providers offer an ‘off the peg’ solution such as Ancestral Origins™ or AncestrybyDNA™, so if you’re interested in these you should shop around for the lowest price. Most providers offer a test that interprets and presents the results in a unique way, so if one of these catches your eye, look for examples of how the results are presented on their website before you buy.