Laboratories such as 23andme and FTDNA now offer autosomal DNA tests that allow family historians to search for connections by matching DNA on any of the chromosomes. Unlike yDNA testing, this approach is equally valid for men and women. Two ladies, Elizabeth Noyes (EN) and Margaret Lawler (ML) took these tests and found that their DNA matched on segments of chromosomes 3 and chromosomes x (see note below for details). The magnitude of the match suggested that they shared a common ancestor 4 or 5 generations back.
Both had traced their family history and both shared the unusual surname Tozer which is associated with Devon in England. But neither had traced far enough to see how they were related. In cases of this kind, it can take a lot of work to find the actual connection. But here there was a useful clue in that the two donors shared some of their x DNA.
X chromosomes can never be passed on from father to son. However, they can be passed from father to daughter, from mother to daughter, and from mother to son. Because surnames are usually passed from father to son, the inheritance of x DNA does not usually accompany the inheritance of a surname. It is apparent, that if the link is through the Tozer surname, this can only occur in a limited number of ways.
ML's great great grandmother was Frances Joanna Southcott Tozer (born 1808 Southwark, died 1848 Lambeth) - four generations back.
EN's great great great grandmother was Joanna Tozer (born 1759, Cadbury, Devon, died 1836, Lambeth) - five generations back.
Both family trees show that it was possible for ML and EN to inherit x DNA from their ancestor because no 'father to son' relationships occurred.
Both Frances Tozer and Joanna Tozer had fathers called William Tozer. But it is clear from the dates, that these could not be the same men. They must be at least one generation apart.
Frances's father was a William Tozer born about 1770 in the Exeter area of Devon. His birth year is estimated from his death certificate which gives his age as 58 in 1828. No marriage has been found to his wife Margaret, and there are several baptisms in Devon that could be his. From his genealogy webpages, Tom Willetts tells us that William Tozer opened a chapel in Southwark 1805 for the followers of Joanna Southcott - a self-described 'religious prophetess' - his daughter was named after her. (See the Wikipedia entry for Joanna Southcott.)
Turning to the other family, Joanna was daughter of the other William Tozer and his wife Ann Hill. They were married at Thorverton in 1748 and had three other daughters baptised there before Joanna's baptism in nearby Cadbury. See the page about the Pitts family.
I can only see two ways to account for the x DNA shared by the two families. The first, and more likely possibility is that the two William Tozers are father and son. This tree shows how they are connected. The people shown in italics all share the x DNA that was passed down to ML and EN.
The other, less likely possibility is that one of Joanna's older sisters had a son out of marriage and gave him the name William Tozer.
It is unfortunate that no baptism was found for the younger William: it is possible he received a non-conformist birth ceremony.
I believe these are the only two possibilities because I cannot see any other way the x DNA could be passed on. But it would certainly help to have further evidence, such as a baptism for the younger William Tozer, or DNA connections to other descendants of these families. I would welcome comments and criticisms.
Richard Phillips firstname.lastname@example.org
The autosomal DNA comparison was done on gedmatch.com comparing Elizabeth Noyes (M031124) and Margaret Lawler (M645439). The stronger matches were:
Chromosome 3: 128 - 144M, 15.2 cM and 184 - 187 M, 6.0 cM.
Chromosome x: Six segments total 11.5 cM adjusted.
MRCA was predicted as 4.7 generations.