DNA Test details

The DNA tests associated with the family genealogy are as follows.

Michael Jefferies; Tests on Ancestry, MyHeritage. Result connected to the Wansbury Family Tree on Ancestry. Y-DNA test on FTDNA at Y700 level. Currently there are 21,000 matches on Ancestry & 10,150 on MyHeritage.

Louise Simon; test on Ancestry; result connected to the Mead/Gough Family tree on Ancestry. DNA also uploaded to MyHeritage on Michael Jefferies' account. Currently there are 17,550 matches on Ancestry & 14,410 on MyHeritage

Nicholas Galton Jefferies; test on Ancestry; result connected to the Mead/Gough Family tree on Ancestry. DNA also uploaded to MyHeritage on Michael Jefferies' account. Currently there are 19,000 matches on Ancestry & 12,5050 on MyHeritage

Melissa Clark; test on Ancestry; result not connected to a Family tree on Ancestry. DNA also uploaded to MyHeritage on Michael Jefferies' account. Currently there are 20,200 matches on Ancestry & 11,500 on MyHeritage

Elinor Nash; test on Ancestry; result not connected to a Family tree on Ancestry. DNA also uploaded to MyHeritage on Michael Jefferies' account. Currently there are 17,650 matches on Ancestry & 14,510 on MyHeritage

The resource numbers on GEDmatch for Michael Jefferies are several but the resource that combines the analysis of both tests (Ancestry & MyHeritage) is MX941038C1. The resource number for Nicholas Jefferies' test is RT6486642. These resources are free to use for anyone with a GEDmatch account. This means that if you have a test on GEDmatch you can look for matches to these tests and then identify where the match is and what other tests also match.

Over the past 2 years Ancestry has introduced tools that divide matches to paternal and maternal lines, or unassigned and of Pro tools which are particularly how in identifying how close shared matches are to one another which narrows down degrees of relatedness.

Where I have data on actual chromosome structure from MyHeritage and GEDmatch I use a program called DNA Painter.  This has allowed links between matches to be explored more effectively. Much more work is being done to paint individual maps for each of the 5 tested family members and this takes time. The analyses done so far have shown some groups with shared DNA but with, currently, no documented links to ourselves as well as confirming known family groups with common ancestors.

The DNA analysis created on DNA Painter for Michael Jefferies is at this link.  This is the most comprehensive of these analyses at the time of writing.  Currently about 57% of the genome is on this page.  Remember that this is a work in progress as more data is added and the way the data is handled may change over time as specific matches are labelled more accurately or reassigned to other lines.

Also for Michael Jefferies (me) there are on Ancestry 384 matches at 4th cousin level or closer. In practical effect this is pointing to ancestors at my g-g-grandfather level who will be in the ancestry of those matches.

Matches that involve shared segments below 10cM are known to be problematic. While we have some persons with known paper links found by matches of less than 10cM this can be misleading; the Blog 'The Genetic Genealogist' by Blaine Bettinger, has articles around this issue including THIS ONE if you are interested.

A summary of this article is:-

"Many to most small segments (at least 7 cM and smaller) are FALSE, meaning they are NOT actually shared by the two matches, and therefore do NOT indicate shared ancestry;

This is supported by a 2014 paper by 23andMe scientists showing that at least 33% of 5 cM phased DNA segments are false-positive (and it’s much worse for unphased segments or segments smaller than 5 cM);

This is further supported by evidence that anywhere from 20-35% of distant matches at a testing company are not shared with either tested parent;

This is further supported by evidence that phasing your DNA with two tested parents significantly reduces the number of matches below 10 cM (with proportionally more matches reduced as the segment size gets smaller);

There is currently no evidence that triangulating segments or finding a paper trail provides a mechanism for distinguishing between false segments and valid segments;

Since we can’t tell the difference between false small segments and valid small segments, we must avoid these small segments to avoid poisoning our genealogical conclusions with false data; and

Beware any research or conclusion that uses these small segments without specifically addressing the issues that are known – based on all the scientific research and evidence gathered to date – to surround small segments."

I am reaching out to persons who are identified by these processes and welcome any such requests. I have some very helpful replies in some cases and none, so far, in others.

The Y-Dna test was done at the Y700 level, the number of positions analysed which gives an accurate result back for some 3000 years. No persons with the Jefferies name has been found on this test as yet.

Revised January 2025

From February 2025 this site is being restructured and rebuilt with new sections. The person names and id numbers are unchanged. Some pages with family background and DNA research findings will contain less information than others as work progresses.