3 DNA websites to help family historians get the best from your tests

Once you understand the basics, you can use your discoveries to expand your research and watch as it stretches not only into your family’s past but the present too, as you begin to find distant relatives spread across the globe.

Graham S Holton and Alasdair F Macdonald, from the University of Strathclyde’s Genealogical Studies Postgraduate Programme, expertly explain the principles of DNA and how testing can benefit the genealogist in the DNA special February 2020 issue of Family Tree (in shops from 14 January or buy here).

They take a look at 4 types of testing:

• Y-chromosome (Y-DNA)

This is very useful in searching specific surnames as the Y-chromosome is only carried and passed on by males. It is also passed down the male line virtually intact, in theory meaning unbroken male lines can be traced for hundreds, even thousands, of years. The disadvantage is that it only focuses on one ancestral line out of multitudes, so does not report anywhere near the large number of matches found in autosomal DNA testing (see below).

• Autosomal DNA (atDNA)

This is useful for corroborating genealogical links, bridging gaps in traditional sources caused by illegitimacy, adoption or missing documentation and can also enable the identification of a common shared ancestor or ancestral couple in the last five or six generations.

• Mitochondrial DNA (mtDNA)

This has a parallel path of inheritance to the Y-chromosome. While Y-DNA is only inherited down the male line, mtDNA is only inherited down the direct female line as it is passed from a mother to her children, but only her daughters can pass it on. Even with an exact mtDNA match the time frame for when a common ancestor was shared can be anything from several hundred years ago to several thousand years ago or more.

• X-chromosome (X-DNA)

Males inherit a Y-chromosome from their father and an X-chromosome from their mother so are XY. The X will in most cases be a recombined mix of both of their mother’s two X-chromosomes. Meanwhile, women have two X-chromosomes, one inherited from their mother, which is usually a recombination of their mother’s two X-chromosomes, and one intact from their father, so are XX. The pattern of inheritance of the X-chromosome can be particularly helpful for women who do not know anything about their biological parents.

Online DNA tools

Here are 3 of the online tools that Graham and Alasdair suggest you use to get the most of your DNA test results, once you have them:

• GEDmatch 
It is important to have your DNA in as many of the databases as possible, including GEDmatch. That way you have a better opportunity for matching.

• FamilyTreeDNA 
It's well worth joining a DNA project for your surname or haplogroup (major genetic grouping) of interest and many thousands are hosted on FamilyTreeDNA.

• DNA Painter
The DNA Painter website is designed to ‘demystify your DNA results’. It will help you to identify which segments of DNA have been inherited from which parent (known as phasing).

*This is an abridged version of the article, 'Gene therapy', by Graham S Holton and Alasdair F Macdonald, published in the February 2020 issue of Family Tree. Don't miss this special February 2020 DNA issue of Family Tree to learn much more about the different types of DNA testing, which is best for you, and the online tools  and resources to help you take your ancestry research even further!

QUICK LINK: Discover how DNA can enrich your family history