The DNA Story

In the Spring of 2000 an article appeared in the British press telling of a study made by Prof Bryan Sykes of Oxford University of the genetic make-up of a number of persons bearing his own name, but not - as far as he knew - related to him or to each other. To his surprise he found evidence of an unexpectedly close relationship between many of the persons tested. Some time before the article appeared I, and a number of other Blencowes of my acquaintance, had received a letter from Prof Sykes describing results of his investigation and inviting us to participate in a similar survey of persons bearing the Blencowe name (in this spelling). The results of that survey are eagerly awaited. This is an attempt at describing what the 'DNA Story' is all about in terms that I hope will be understandable! The letters DNA stand for DeoxyriboNucleicAcid, a complex molecule that carries genetic information from one generation to the next. It occurs in the nuclei of cells and also in the cell-sap ('cytoplasm'). The DNA in the cell-sap passes from mother to daughter in the egg cell, permitting the scientist to study the ancestry of organisms, including humans, through the female parentage. Prof Sykes' research on this type of DNA in human beings has revealed that virtually all the European races have been derived from less than a score of individual females who entered the continent from Africa a thousand or more generations ago!

The DNA in cell nuclei occurs in pairs of rod-like bodies called chromosomes; in humans there are 23 pairs. When male sperm and female egg cells are produced the pairs separate so that each cell has 23 single chromosomes; after fertilisation the embryo has again 23 pairs, with one from each parent. In this way genetic information is passed from parent to offspring and variability arises from the re- combination of chromosomes from the two parents.

There are differences between the chromosomes of male and female. The human female has 23 pairs, the male has 22 pairs plus two dissimilar ones. These latter are termed the 'X' and 'Y' chromosomes; the corresponding pair in the female consists of two 'X' chromosomes. The female egg will always have one 'X' chromosome, the male sperm either an 'X' or a 'Y'. An embryo with an 'XX' make-up will be female, 'XY' will be male. This means that the 'Y' chromosome passes from father to son in unbroken sequence. Mutations do occur but very infrequently, probably at intervals measured in hundreds rather than scores of generations. Very close similarities had been found in the male chromosomes of the Cohens, who for centuries provided the hereditary Jewish priesthood; Prof Sykes set out to make a study of a family group where marriages had been made in a more random manner. He chose his own name which is relatively unusual, found most commonly in West Yorkshire, Lancashire and Cheshire, and with records going back some 700 years.

DNA samples are collected by scraping the inside of the cheek with a tiny brush; the genetic material in the few cells scraped off can be multiplied up to give enough for tests to be made. He was given samples by 61 volunteers of which 48 were tested successfully. To compare what he might find in the Sykes samples with the rest of the population he also asked the volunteers to obtain scrapings from un- related neighbours. Also included were samples from 139 English-born males from all over the country. The results were surprising; 21 of the Sykes samples had an identical group of genetic 'markers' on the 'Y' chromosome, a grouping that was not found in any of the 'neighbour' or 'English' samples. Four others exhibited just a single genetic mutation. In simple terms, those 21 men had descended - in unbroken succession - from a single male ancestor!

The 'Blencowe' study should reveal similar close relationships for our name is not a regional one but derives from that single tiny village near Penrith. There will be some obvious limitations; the male descendants of the southern (Marston St Lawrence) branch of the family will carry a 'Y' chromosome from their Jackson ancestor, who was adopted into the family in the John Blencowe of the day died s.p. in 1777. In addition to adoptions there will also be instances where the male line has been broken by illegitimate births; descendants of Thomas Blencowe who was transported to Australia in 1835 would be found to be related to one another, but not to the main ancestral line. The many descendants of Dorcas Blencowe of the Whilton family would not have the 'Y' chromosome inherited from John Blencowe of Whilton and Marston St Lawrence but that from her son Benjamin whose father was probably named Ward.

These DNA studies open up exciting prospects for family history research. It should be easy to find whether families with the many different spellings of our name really are related to one another. However, there are other implications, and for this reason all the samples have been collected under conditions of medical confidentiality. It is not just that unexpected evidence of paternity might emerge, there is already an ethical debate as to whether insurance companies might use genetic information to adjust life insurance charges to risks of inherited diseases. Things have come a long way since I studied cyto-genetics as an undergraduate in 1942-4, but even then it was possible - with quite an ordinary microscope - to see the transverse stripe patterns on the 'giant' chromosomes of the fruit-fly Drosophila and it was reasonable to speculate that these were related to the known sequences of genes carried on them. The importance of the DNA tests for police work is obvious. Criminals are already being convicted on the basis of DNA samples collected at the scene of crimes. Within a few years it might be possible for the word to go out, not just, “Look out for a caucasian male” but “Check up on guys named Blencowe”. However, we're probably a long way off from, “He probably calls himself Jack”!

Jack Blencowe, Oxford, U.K.
December 2000

When I last met Prof Sykes he showed me the preliminary results of the Blencowe survey. To his surpise, but not mine, there was one major group and two other separate but distinct groups (plus quite a small numnber of 'odd bods').. Because some of our number had already spoken to me about submitting samples it was clear that one sub-group descends from an illegitimate birth in 1803 and I would guess that the other sub-group descends from Samuel Jackson Blencowe (see above). Further details will only come to hand when the results are sent out individually and confidentially. We agreed that he would invite those who wished to do so to send the results to me to collate and produce a more personalised summary.

When I first met Prof Sykes I asked, and he agreed in principle, to include a number of persons in the survey to represent different spellings of our name and pof a few important emigrant lines: descendants of James Blincoe who appeared in American records in 1670, the Blencoes of Wisconsin and the Blincos of Elora in Ontariio. In the event, he has not been able to do this. We must realise that 'Blencowe' was not the only name in his study, and that there is a limit to expenditure of public research funds - the apparatus used costs half-a-million dolars. The work had attracted attention from genealogists and a public company has been set up to undertake studies on a commercial basis. The company is called Oxford Ancestors and you can read all about it on a web site: www.oxfordancestors.com

I understand that charges will be about $180 per sample; it sounds a lot of money, but when I think of what it cost me for a few train journeys to the London Records Office, plus the charges for birth, marriage and death certificates, it doesn't sound too bad. Perhaps some of our Family Association members would care to get together and decide on selecting a few key persons; it could be one way of finding out whether Blincows, Blincoes, Blencoes, etc. are actually all Blencowes.

Blencowe Family Association Home Page

updated: 6 May 2001