'It is a popularly held belief that there are two distinct McManus families - both Irish, one emanating from the Maguires of Fermanagh and the other from the O'Conors of Roscommon. An objective of this project is to test this hypothesis.'
There is a need to understand some of the difficulties attached to successfully achieving the above objective. Chaos and complexity and, therefore, uncertainty, abound in biological and social systems - remember Lorenz and the butterfly? Some of the problems that can arise in DNA analysis come from:
low volume of participants and, therefore, a dearth of comparisons;
an extra-marital event;
major divergence due to sudden mutation in a short number of generations possibility caused through diet or environmental changes;
a fact differing from traditional accounts due to inaccuracies;
a fact differing from traditional accounts due to downright falsehood or fabrication;
confusion of families;
a low number of DNA markers tested, together with acceptance by individuals of their comparative value:
Uncertainty about calculating The Most Recent Common Ancestor (TMRCA)
To take four of these; few participants, inaccuracies in origins, low numbers of DNA markers and uncertainty in calculating TMRCA:
If we had a certain and indisputable Roscommon and Fermanagh DNA profile from a participant we would have a template from which to proceed. But what if, beyond the present day memory and research capacity of a participant's family, a Roscommon or Fermanagh McManus emigrated to the other place many years ago? We may then have a mixed and confused template. Ideally, we need several participants with reasonable documentary evidence of their family's geographical origins. Then we could perhaps speak with certainty of a Fermanagh or Roscommon haplotype. I would argue that the number of participants we have currently doesn't satisfy this requirement. We need more participants!
An indisputable pedigree which identifies the current holders of the Chiefships of the Clans Maguire and O'Conor, from which the Fermanagh and Roscommon lines emanate respectively, would provide another template to work off. Unfortunately, there are many examples which can be given of inaccuracies, and even shameless falsehood, in the genealogies of some claimants to Chiefships. Some have been declared invalid by the Herald of Ireland and others are disputed and are currently under investigation. The work of Murphy (2002) is illuminating in this respect. He brings our attention to many disputed claims, including that of the styled, Maguire, Prince of Fermanagh, Terence Maguire, of our own line. Murphy points out:
An undocumented pedigree is not a sufficient basis on which to grant recognition of a Chiefship, and the Genealogical Office should have rejected the Maguire claim on this point alone. It would appear that the above pedigree is based on sentimental family imaginings at best, brazen fabrication at worst, as evidence has been found that the son and grandson of Thomas Maguire were not named Conor and Donal, but Thomas and Hugh. http://homepage.eircom.net/~seanjmurphy/chiefs/maguire.htm
So, there will be problems of 'certainty' for the standard of the models from which to begin the project. But even if we did have certain model Chieftains from whom we could work, another problem arises and that is this: they may not have provided, and may have no intention to provide in the future, DNA profiles of themselves. To date, Desmond O'Conor, current claimant to the O'Connor Chiefship, has not provided DNA samples. Therefore, unless we can show many identical or similar DNA profiles, and associated documentary research reinforcing these amongst participants to the project, we must be careful not to take ‘leaps of faith’ and engineer our own version of history. Based on the current low volume of participants in the project, therefore, it is reasonable to conclude that until there are many more to compare, we need to be circumspect on the results, not just on participant's pedigrees but on their original Irish geographical locations too. In view of this, unless any participant can show undisputed registration of a long pedigree with the Irish Genealogical Office, then any claim will be considered 'unverifiable'. That doesn't mean, however, that we can't have imaginative analysis based on these long pedigrees. Having said this, however, it has also got to be said that by August, 2004, an 'Ulster' haplotype appears to be emerging from the results.
A low number of DNA markers tested, together with acceptance by individuals of their comparative value, makes us take genealogical jumps of faith to ensure a 'match'.No significance should be attributed to comparisons unless the number of markers tested is 20 and over:
Too few test markers, e.g. 10 or 12, can often give inconclusive results. These 'low-resolution' tests can really only confirm that two people are NOT related, thus the vast majority of genealogists find they need to upgrade to a more accurate test anyway.............20+, are enough to answer your genealogical questions.
An honest and generally accepted rule is that, if you have 43 markers tested, a 43/43 match is excellent, a 42/43 match is good and a 41/43 match is okay. Any more and it is increasingly unlikely to share a common ancestor although it may be possible to find a 'bridge haplotype' e.g. from a cousin in the middle which will help link people together. What you expect to see within an extended family is for many people to have the same result, with others with one or two mutations. If you were to plot this graphically, you would get a 'star-cluster' with the most common haplotype in the middle and others dotted around the outside. When you get down to 24 markers, a 24/24 marker match is good and a 23/24 marker match is okay. Anything less and it will be increasingly unlikely that there is a close match, although a 22/24 match can be observed and still be within the boundaries. There is, in fact, variation in interpretation between testing laboratories. So, 'certainty', again evades us.
Calculating TMRCA is merely a 'guide' which can show possibilities on a continuum of great variance in time. It should not, therefore, be taken too seriously. Personally, I do not dismiss it altogether, but I still see it as 'a bit of fun'.
Murphy, S.J. (2002) Atavus, the online magazine for Burke’s Peerage, Vol. 1 (2). See also Murphy’s work at http://homepage.eircom.net/~seanjmurphy/chiefs/maguire.htm concerning Maguire of Fermanagh and other Irish Chiefs at http://homepage.eircom.net/~seanjmurphy/chiefs/.