Putting the genes into genealogy – Part 3

Updated 17 Sep 2017

“If there’s one thing I’ve learned about DNA testing, it is that patience is required.” I wrote those words two years ago, in June 2015, in the first of this series of articles (see Putting the genes into genealogy – Part 1). In the same article, I described genetic genealogy as “a waiting game”. Well, I may not have been entirely patient over the last couple of years, but the long wait has been worthwhile. We have some answers regarding the ancestry of the Atcherley family. And, inevitably, some more questions!

I launched the Atcherley Surname DNA Project at Family Tree DNA (FTDNA) in August 2015. Back then, I suggested on this site’s new DNA page (which now needs a re-write) that we might learn whether the Atcherleys were natives of Shropshire, or maybe descendants of Norman invaders. I also hoped that we would find out “whether the Atcherleys of northern Shropshire were from the same stock as the Atchleys from the south of the county, or the Ackerleys of Cheshire.” Additionally, I opined that “DNA testing may even throw up surprises which haven’t been considered!”

As I noted in 2015, the Atcherley DNA Project relies on “analysis of the DNA of Atcherley men living today, who have genetic information on their Y chromosomes which has been passed down from their paternal ancestors.” “Without participants,” I wrote, “the project will not achieve anything”. I then appealed for male Atcherleys to consider taking part. I am pleased to say that my plea was answered.

Martin Atcherley, an 8x great grandson of Thomas Atcherley of Marton, was the first to join the project and provide a cheek swab for testing (a FTDNA DNA test kit is pictured above). In 2016 another male Atcherley, from a different branch of the family, also tested – but his yDNA did not match Martin’s. This result had one of two explanations. The first was that the two main branches of the Atcherley family tree did not have the common ancestor I believed they had. The second possibility was that somewhere along the paternal line of one of our Atcherley test subjects there had been a ‘NPE’.

A NPE is a Non-Paternity Event, a rather strange term to my way of thinking because it seems to imply a lack of male involvement in the process of reproduction! I prefer to think of it as a ‘Non-spousal Paternity Event’, because an NPE basically refers to a child being born out of wedlock and not receiving its father’s surname. The connection between the Y chromosome and the surname which is usually inherited with it is broken in such an event.

A very different result was the outcome of a third Atcherley yDNA test, taken this year by Dave Atcherley. Dave is a 9x great grandson of Richard Atcherley of Stanwardine, and so he is (like our second test subject) from the ‘opposite side’ of the Atcherley family tree to Martin. But his 37 marker yDNA test shows that Dave does match with Martin, with a Genetic Distance of 3. A great result, as it indicates that the two main branches of the Atcherley tree do have shared roots as I have long thought.

On your markers, get set, go the genetic distance

But wait, what’s all this “37 markers” and “Genetic Distance” stuff? OK, let’s get technical (but hopefully not too technical) for a few moments. The ‘markers’ on the Y chromosome which are tested are more accurately known as STRs or Short Tandem Repeats (or to be even more accurate, variable number short tandem repeats). These are segments of DNA comprised of short, repeating sequences of the chemical bases of which DNA is made. Each of these STRs or markers is given a value equal to the number of repeats of its bases. The marker known as DYS439, for example, can range in value from 5 to 19, but most men who have been tested have from 10 to 13 repeats.

The variations in the value of each yDNA marker arise through mutations – errors in the DNA copying process (which takes place, in this case, when sperm cells are made). Some markers are very stable, mutating rarely, while others are more volatile and mutate more frequently (the above-mentioned DYS439 is among the most mutation-prone STRs). Counting the values of a range of these markers gives a set of results which can be used to compare one sample of yDNA with another. The more markers tested, the better the comparison – a 37 marker test is considered to be the minimum required to be useful for determining relationships in surname studies.

Across the 37 markers on which both Martin and David Atcherley have been tested, there are only three differences – hence the Genetic Distance of 3. For DYS439, Martin has a value of 11 while Dave has 12  (now you can see why I used this marker as an example in the paragraphs above). DYS464 is another relatively volatile STR and is a ‘multi-copy’ marker of which which most men have four copies (with the value of each copy ranging from 9 to 20). Martin’s figures for this marker are 14-15-17-18 and Dave’s are 15-15-17-17 (see screen grab, right). Two separate mutations have therefore taken place on this STR to differentiate Martin and Dave over the generations that separate them.

By how many generations are Martin and Dave separated though? There can be no precise answer to this question. The Genetic Distance of 3 over 37 markers is close to the limit (4) beyond which FTDNA does not report a ‘match’ between two sets of yDNA results – so although they are related, the degree of relatedness is apparently not close. As we have seen however, given the varying rates at which yDNA markers mutate Genetic Distance can be a bit of a blunt instrument. Another surname study (for Owston/Ouston) has also questioned the reliability of Genetic Distances for inferring relationships (see References below).

The different mutation rates for the markers being compared in a yDNA test are however taken into consideration in a FTDNA tool known as TiP (Time Predictor). This calculates the approximate number of generations we have to go back to get to the common ancestor of two men who have taken the yDNA test. For Martin and David Atcherley, with no common ancestor known in the last 10 generations, FTDNA’s TiP suggest a 90% probability of them having a common ancestor around 15 to 16 generations ago. As we go back further the odds get better, reaching a probability of 99% when we reach 21 generations. My semi-educated guess is that we are looking at a common ancestor who was born in the 1400s – or thereabouts! (See the update at the end of this article.)


What other findings have emerged from these yDNA tests – what of the possible links with the Ackerleys of Cheshire or the Atchleys of South Shropshire, for example? And what of the surprises which I thought were possible? Well, so far there are no matches between our Atcherleys and anyone with the surname Ackerley. But we do have Atchley matches – and some Ashley matches too!

Atcherley, Atchley and Ashley are phonetically similar and it is easy to see how they might have evolved from the same roots. I am pleased to report that the yDNA kits of three Atchleys, and also three Ashleys, all from  the USA, have been added to the Atcherley DNA Project, allowing me to analyse the connections between them. Here (see right), for starters, is a chart showing the Genetic Distances (at 37 markers) between the eight participants.

The Genetic Distance results suggest that Dave Atcherley is more closely related to K and B Ashley and J Atchley (1) than he is to Martin Atcherley. If true, that would indicate that the Ashleys and Atchleys branched off from the Atcherley line leading to Dave, after Dave’s and Martin’s lines diverged from each other. There is however another way of looking at the genetic relationships between these A*h*ley men, and that is by focussing on the variations (mutations) of the yDNA markers which differentiate them. Here (below) is a diagram which shows just that.


As you can see, tracing a line between any two of the men on the above chart and counting the mutations along the way gives the genetic distance between them. The chart suggests that the Ashleys might be as closely related to Martin Atcherley as they are to Dave Atcherley. On the other hand, the closer relationship between Dave and the Atchleys is possibly upheld, although the peculiarities of the DYS464 marker results (and how they are used in calculating Genetic Distances) is not fully reflected in the diagram.

I should make it clear that these results do not mean that all Atchleys and Ashleys are related to the Atcherley family. The Ashleys who match on the yDNA 37 marker test are from one particular line which can be traced back to Ashley ancestors living in Chowan County, North Carolina, in the 1700s. These Ashleys do not match with others bearing their surname. The exact circumstances in which an Atcherley gave rise to the Ashleys of North America are not known, nor is the time or place of this event. There is however an example of an Atcherley who was also known by the surname Ashley. Peter Atcherley of Stanwardine in the Fields, Shropshire, baptised at Baschurch on 30 May 1664, was a military man who was referred to as “Peter Atcherley, alias Ashley, esq.” when commissioned as captain “of a troop to be forthwith raised and added to the regiment of dragoons commanded by Thomas, Lord Fairfax” in 1690.

It is a similar situation with the Atchleys. Those who match with Martin or Dave Atcherley (or with both of them) on the yDNA 37 marker test are those who can trace their paternal line back to a Thomas Atchley, who is believed to have been born in England (possibly Staffordshire) around 1695 (some refer to him as James Atchley, and/or claim that he was of Scottish descent). This Thomas migrated to America and married Ruth Maple, before or after he settled in New Jersey where he died, on 14 January 1775, at Brunswick, Middlesex County. His Atchley descendants do not have yDNA matches with other Atchley lines in America.

The possibility that Thomas was born Shropshire, to an Atchley father descended from Atcherley forebears, is certainly worth considering given the DNA evidence. With this in mind, an entry in the parish register of Ludlow dated 27 December 1696 is of interest. It records the baptism of Thomas, son of Edward Achley and his wife Mary (probably the Edward Achley and Mary Porter who were married at Ludlow on 19 May 1692). This is far from being a conclusive link, but it opens up an avenue which I think is worth exploring.

Next steps

What next? Tracking down a few more Atcherley (and related Atchley / Ashley) men willing to join the Atcherley DNA project and provide a cheek swab is definitely on the list – can we find any Atchleys in the UK who might have Shropshire ancestors? Upgrading some of the existing yDNA 37 tests to 67 markers for more detailed analysis is also planned (one such upgrade is already in progress). A review of A*h*ley records from the Shropshire area in and before the 1600s is also on my ‘to do’ list.

As you can see, I am far from finished with putting the genes into the genealogy of the Atcherley family!


67 marker upgrades have now (17 Sep 2017) been completed for both David and Martin Atcherley. All of the additional 30 markers tested are identical, which means that the Genetic Distance between these two Atcherleys remains at 3, but over 67 markers (a 64/67 match). According to Family Tree DNA, “A 63/67 or 64/67 match between two men who share the same surname (or a variant) means that they are likely to share a common ancestor within the genealogical time frame. The common ancestor is probably not extremely recent but is likely within the range of most well-established surname lineages in Western Europe.” With no common ancestor known in the last 10 generations, FTDNA’s TiP now suggests a 90% probability of them having a common ancestor around 14 generations ago, with a probability of 99% now reached at 19 generations back.

Comment on the Atcherley.org.uk Facebook page

Acknowledgements: I extend my grateful thanks to the men of the Atcherley, Atchley and Ashley families who have taken yDNA tests and who have, directly or through kit administrators, joined the Atcherley Surname DNA Project. Full names are given only where those involved have agreed to this.

Picture credits. Family Tree DNA test kit: photo by the author. Screen grab: from Family Tree DNA Atcherley DNA Project Y-DNA Results page. Table and chart showing A*h*ley yDNA Genetic Distances and genetic tree: by the author.


[1] Atcherley Surname DNA Project Results. At: Family Tree DNA website (results available to project members only). Last accessed 25 June 2017.
Non-paternity event. At: ISOGG website (accessed 25 Jun 2017).
[3] Locus Information on DYS439. At the YHRD website (accessed 25 Jun 2017).
[4] H Y Lee et al (2006), Haplotypes and mutation analysis of 22 Y-chromosomal STRs in Korean father-son pairs. In: Int J Legal Med., 121(2): pages 128-35 (Epub 15 Nov 2006). Abstract viewed at PubMed (website, accessed 25 Jun 2017).
[5] List of Y-STR markers. At Wikipedia (website, accessed 25 Jun 2017).
[6] Kenyon DNA Project. At: Kenyon Genealogy website (accessed 25 Jun 2017).
[7] How to Take Part. At: Manx DNA website (accessed 25 Jun 2017).
[8] DNA Test Kits. At: Your Scottish Ancestry website (accessed 25 Jun 2017).
[9] DYS 464. At ISOGG website (accessed 25 Jun 2017).
[10] Jim Owston (2014): Is Genetic Distance an Adequate Predictor of Relationships? At: The Lineal Arboretum (blog, accessed 25 Jun 2017).
[11] How do I tell how closely I am related to a Y-chromosome DNA (Y-DNA) match? What is FTDNATiP™? At: Family Tree DNA website (accessed 26 Jun 2017).
[12] K Ashley (2016-17), personal communications.
[13] HMSO (1906), Calendar of State Papers, Domestic Series, of the Reign of William and Mary, 1694-1695. Page 47.
[14] Paul Layman Atchley, Mary Ann Morris Thompson (1965), Maud Horn’s Atchley Family History. Snippets viewed at Google Books.
[15] T G Maple (2000), Maud Horn was wrong! At: Ancestry Message Boards (online, accessed 26 Jun 2017).
[16] James Thomas Atchley (abt. 1695 – bef. 1775). At: Wikitree (website, accessed 26 Jun 2017).
[17] Ludlow, Shropshire, England, parish register covering 1696. Entry dated 27 December for baptism of “Thomas Son of Edward Achley & Mary his wife”. Copy viewed at Findmypast – Shropshire Baptisms (surname transcribed as Ackley – correction submitted).
[18] Ludlow, Shropshire, England, parish register covering 1692. Entry dated 19 May for marriage of “Edward Achley & Mary Porter of this parish”. Copy viewed at Findmypast – Shropshire Baptisms (surname transcribed as Ackley – correction submitted).