The Layman family has many branches, or perhaps the branches are independent. There are certainly many different spellings. In the Social Security Index there are 18 spellings, but more than this are known from research. Some of the spellings are Lehmann, Leman, Laman, Leaman, Lamen, Lemen, Layman, Lemon, Lemons, Lemmon, Lemmons, Lamon, Laymon, Laymance, LaMance, LaMond, Lemond, and Lemmond. Descendants claim origins in Switzerland, Germany, Ireland, and Scotland. Which of the surname spellings is for a distinctly different family and which are merely variations of spelling? Researchers in all of these branches could not agree. Fortunately, some progress has now been made by DNA testing.
For the same surnames, including the spelling variations, the Y chromosome test is appropriate. Only males have the Y chromosome and it is inherited from the father, usually unchanged; however, in the DNA strand, the important elements or genes are separated by spacers which are essentially inert. The numbers of these spacers may vary from generation to generation, though usually it is the same. The probability of a change in the number of spacers is about .002. That is, there is about two chances in a thousand that the number of spacers will change from father to son in any gene. If I have done my arithmetic correctly, in ten generations, there may be a change in two in every hundred cases for one gene. Or stating it in the opposite sense, 98 times out of a 100, a tenth generation descendant will have the same number of spacers or score as the progenitor.
The Layman family used ten markers or genes and measured the number of spacers in each. It is not uncommon for two tenth-generation descendants to have the same scores across all ten tests. If they do, we feel confident that they originated from the same individual. But because the scores or results are dependent upon random factors, they might differ by small amounts. A difference of two in the scores across the total of ten tests for two men would strongly suggest a common ancestor.
Because of the statistical nature, a difference cannot be used to say how many generations there might be in two individuals. The larger the difference, the more certain it is that there is no common ancestor or that the common ancestor was very removed.
The score for one individual, for the ten tests, might be 14, 12, 24, 10, 13, 13, 10, 17, 12, 12. None of these numbers is significant in itself. They represent inert spacers which tend to repeat from generation to generation. In comparing two individuals, what is important is the number and magnitude of the differences in total.
Applied to the Layman family, descendants of Peter Leman, who arrived in 1717 as a German-speaking Swiss Mennonite, form one large branch, many of whom spell the name differently. The majority of his proven descendants show no change or one change. This confirms the non-genetic research and shows that changes in the markers are relatively rare.
(31 Jan 06)
We gratefully acknowledge the work of John Blankenbaker who published over 2,500 Germanna History Notes via the Germanna-L@rootsweb.com email list from 1997 to 2008. We are equally thankful to George Durman (Sgt. George) for hosting the list and republishing the notes via rootsweb.com.