The first line of descent, to cabinet-maker Michael Ibsen, included a number of women whose husbands and fathers - or in one case, daughter/sister/aunt - were notable enough to have made it to Wikipedia. I edited the relevant articles to make reference to this (Sir Robert Constable, Henry Chomley, Thomas Belasyse, Sir Henry Slingsby, John Talbot, Sir Henry Gough, Barbara Spooner Wilberforce, and Edward Vansittart Neale). When the findings were first announced in February 2013, it was also stated that another line of descent had been identified, but that the living individual concerned did not wish to go public. I wondered whether this might be a descendant of the musician Margaret Harrison, referred to in an earlier Guardian piece (one-time fiancée of Percy Grainger, daughter of the painter Peter Harrison and the writer Alma Strettell); and if so whether this would really help much, given that such a person would have been not so many generations removed from Michael Ibsen; any failure of methodology with regard to his lineage would likely apply also to Margaret Harrison and her descendants.
But in fact it turned out to be much more robust. Wendy Duldig, a social policy researcher, is descended from a different daughter of Sir Robert Constable and his wife Catherine (née Manners), Richard III's great-niece, back in the early 16th century, with an extra two generations in her lineage compared to Michael Ibsen. Only two of the intervening links in Wendy Duldig's mother-daughter line had close family members who made it to Wikipedia (Sir George Wentworth and Sir Benjamin Truman), though one of them was painted by Gainsborough.(Truman's granddaughter Frances Read, see right). I found this in itself interesting - it shows that even without historical notoriety, the present-day researcher can pursue good genealogical links through the ranks of the upper middle classes.
It shouldn't be very surprising that such lineages rise and fall in income bracket and level of social prominence over the centuries. Taking it in the other direction, consider Mary Garritt, the wife of Thomas Webb, a surveyor in Stow-on-the-Wold in the mid-18th century. Her daughter Frances (1775-1862) married Thomas Salisbury, landlord of Marshfield House in Yorkshire. Their daughter Anne (1806-1881) married another gentry type, Edwyn Burnaby of Baggrave Hall in Leicestershire. Their daughter Caroline (1832-1918) married a widowed clergyman who was the grandson of a duke. Their daughter Nina (1862-1938) managed to bag an earl as her husband. Her daughter Elizabeth (1900-2002) did rather better than a mere earl. Her daughter, another Elizabeth, was born in 1926 and is still alive; those of you in the UK and Canada will find her depicted on certain useful everyday objects, ie money. But her direct female line ancestry can be traced back only six generations before it is lost in Gloucestershire.
These lineages are in fact very fragile. 17 generations on, Michael Ibsen is 57, and he and his siblings have no children, so the lineage from Sir Robert Constable's older daughter will die with them. 19 generations on, Wendy Duldig, in her fifties, is not reported to have siblings or children either. Had Richard III's remains been discovered forty years later, there might have been nobody around to compare his DNA with. There may be other undocumented maternal line descendants still around, daughters whose descendants were written out of the record for reasons easy enough to envisage; but the Leicester researchers seem to have done a pretty thorough job and it's difficult to imagine that much slipped past them. On the other hand, we know for certain that everyone alive today had at least one female-line ancestor who was alive in 1485. We must all be descended maternally from a fairly small number of women even going back only a few centuries. Mitochondrial Eve is reckoned to have lived 100,000-200,000 years ago, but for a lot of us, our most recent common maternal ancestor will have been much closer to the present day.
A couple of demographic notes. The average mother-daughter age difference in Michael Ibsen's lineage is 30.5 years, which is perhaps a little older than I had expected. The average mother-daughter age difference for Wendy Duldig's lineage is 27.5 years, which I find less surprising. The biggest generational jump is 42 years, between Michael Ibsen's grandmother and his mother. There are just four other births to mothers over 35 among the 33 births in the two lineages - Michael Ibsen's great-grandmother, her grandmother, Wendy Duldig's grandmother, and poor Anne of York who at 37 died giving birth to Anne St Leger in 1476, the link that kicks off the entire process. At the other end, there are no provable teenage mothers, though it's quite likely that at least one of the uncertain early 16th century 20-year-olds would have qualified.
Three women are known to have outlived their daughters (one seventeenth-century, two eighteenth-century). Two of these lived to over 90 (both born in the seventeenth century and living to the eighteenth century). The average lifespan of the women born in the fifteenth century was 43.5 years; of those born in the sixteenth century, 47.8; of those born in the seventeenth century, 62.4 (skewed by the nonagenarians, though the Duldig lineage is also pretty robust in general in that era); for both the eighteenth and nineteenth centuries, 70.6 years; and for the two born in the twentieth century, 79. (I have no data on the ages of the fathers.)
It's also interesting to note that Michael Ibsen's family emigrated to Canada, and Wendy Duldig's to New Zealand; but both Ibsen and Duldig have ended up in London.
Finally, the newspapers had great fun with the other side of the story, that the Y-chromosome analysis for male descent failed; comparison of Richard III's DNA with that of several known descendants of the fifth Duke of Beaufort showed that they did not have a common male ancestor in Edward III, as had been thought from historical records, so therefore at some stage the recorded father-son link did not reflect the biological facts. Does this mean that the entire British royal line is illegitimate? Well, probably not - or at least not for that reason!!! Four generations separate Richard III and Edward III, but the fifth Duke of Beaufort was 15 generations removed from his royal ancestor; on the face of it, it's therefore almost four times as likely that the bogus link is on the Beaufort side rather than the York side. On top of that, of the 15 Beaufort side links, only the first two are shared with Henry VII. So if for some peculiar reason you believe that Elizabeth II has a right to rule Britain and various other places due to Henry VII's descent from John of Gaunt, you can probably rest easy.