Implications of Kit# 159573 Gregory L. Brewer’s signature and Pedigree
Problem: DYS 393 allele value of 14 in Gregory’s signature.
The posted pedigrees of Gregory and William L. are as follows:
Kit 14813 William Lyle Brewer (Weavertrk@aol.com) Haplogroup est. I2b
Contact is Grant W. Johnston
1) Unknown Brewer (b. ca 1800 in NY according to 1880 Menard CO, TX Federal Census) moved to Louisiana before 1825, m. Unknown b. LA
2) William Brewer b. 1826 LA, m. Carolyn Hillebrandt in Jefferson Co. TX
3) Erasmus Andrew (Andy) Brewer, b.1855, Jefferson Co. TX, m. Martha Ellen Click in Bandera Co., TX
4) William (Bill) Brewer b. 1901, Leakey Co., TX. m: Gladys Darling, Klamath Co, OR
5) William Lyle (Lyle) Brewer b.1943, Klamath Co, OR, m. Patricia Mitchell
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Kit 159573 Gregory Laurence Brewer ( yukonangels@aol.com )
1) Unknown Brewer (b. ca 1800 in NY according to 1880 Menard CO, TX Federal Census) moved to Louisiana before 1825, m. Unknown b. LA
2) William Brewer b. 1826 LA, m. Carolyn Hillebrandt in Jefferson Co. TX
3) Elias L Brewer b. 1854, Jefferson Co. TX, m Marion Terry in Menard TX.
4) Jasper Newton Brewer b. 09 January 1890, Vance, Edwards, TX. m. Iva Shank in Arizona.
5) Jasper Newton Brewer b. 29 May 1919 Los Angeles Ca
6) Gregory Laurence Brewer
Most Recent Common Ancestor marked in Red.
Apparently their genealogical research has led them to conclude their common ancestor is William Brewer b.1826 in Louisiana, so we expect a close match in signatures. They do have a reasonably close match, differing in only 3 markers out of 37, meaning they are in fact related. But when? Recently or more distantly? The marker differences occur at DYS#393 (-1), DYS#460 (-1), and DYS#570 (-1). The problem I have with immediately accepting their paperwork showing the Most Recent Common Ancestor ( MRCA) as William (1826) is two fold: (A) the low probability (13%) predicted for them to share a common ancestor in 4 generations as claimed, and (B) the striking difference that occurs in marker DYS#393, which in Gregory carries an allele value of 14, whereas for William L. (and all others in the Jan Brouwer group tested to date) the value is 15. The chart below shows the predicted probability of finding the MRCA as indicated. It really says only that before a validated paper trail is established, one wouldn’t expect to locate the common ancestor so early; in fact it would indicate that the common ancestor may be as far back as Johannes Brouwer or even further back. That is also hinted at in the difference showing up at marker DYS#393 -- it is possible that some relation of Johannes with a 14 headed a line that leads to Gregory while Johannes, experiencing a mutation 14->15, heads the line to William L. and the other descendants. The paper trail, if sound, can override the general probabilities but I will consider this in the discussion to follow.
In comparing 37 markers, the probability that Mr. Gregory L. Brewer and Wm. L. Brewer shared a common ancestor within the last...
4 generations is 13.04%
8 generations is 49.6%
12 generations is 78.33%
16 generations is 92.27%
As far as the difference shown in the value of the marker DYS#393, the question raised is when did that mutation occur? DYS#393 is a relatively stable slowly mutating marker. The mutation rate is .002, or one mutation expected in 500 transmissions of the Y-DNA chromosome from father to son. Of course the mutation can occur at any time and in any generation (the mutation rate is a statistical average) but was it before William, at William, or after William, in Greg’s line? This has an important consequence for determining the ancestral line of Greg and William L. back to Johannes Brouwer and it also has implications for the signature of Johannes. That is what captured my attention.
Because William L. claims William Brewer (1826) as a direct ancestor and his signature at DYS#393 carries a 15, he (and we) would expect that his ancestor William also had a 15 in that spot, especially because his signature relates him back to Johannes Brouwer and all the others who trace back to Johannes have a 15 at that location. This also assumes Johannes actually had 15 at that location.
But Gregory also claims to have William Brewer (1826) as a direct ancestor and his signature at DYS#393 carries a 14, so he (and we) would expect that his ancestor William had a 14 in that location. Otherwise, if William (1826) had a 15, the mutation would have dropped a count 15->14 in one of the three immediate male descendants in Greg’s line: Elias (1854), Jasper (1890), Jasper (1919) or Gregory himself. Because we normally expect mutations to increase rather than decrease in value, it would be twice as likely that William (1826) also had a 14 and that the mutation 14 ->15 occurred in the brother’s line of descent to William L., either in Erasmus, or Bill (1901), or even in William L. That would be a logical conclusion if it were not for the fact that everyone else in the Johannes line known to date has a 15, implying (so far) that Johannes has a 15. If it could be shown that William (1826) in fact had a 14 at that locus, then we would have to consider the possibility of Johannes having a 14, and two separate events occurred:
(1) the other lines to living descendants experienced a mutation 14->15 somewhere down the line from either Derck or Peter -- and --
the same mutation 14->15 occurred again in the short line from William (1826) to William L. In my opinion, the combined sequence of events 1 &2 while possible is highly unlikely, a bit of a stretch.
So, if we exclude that possibility it again implies one of two situations:
William (1826) had a 15, which was transmitted unchanged to William L., but somewhere in Greg’s line --Elias, Jasper (1890), Jasper (1919) or Gregory -- there was a mutation that decreased the value 15->14.
Either that, or possibly
The line from Gregory does not descend from William (1826), but rather follows a separate line back to a relation of Johannes Brouwer, perhaps in the old country, that passed on a 14 unchanged and that Johannes originally inherited a mutation that was an increase 14 ->15.
Well, I guess I am forced to conclude that the 14 was one of those random occurrences that decreased the value from 15 ->14 and that it occurred in the short span of time between William (1826) and Gregory, within only three generations: Elias(1854), Jasper (1890), Jasper (1919) or Gregory. A conclusion I would normally be loathe to accept. We either challenge the genealogical pedigree, refuse to accept that William (1826) is the common ancestor of Greg and William L, and then have to consider some strange line back to the old country or an unknown relation to Johannes. No, I guess the simplest solution is to accept the unusual negative mutation and the pedigree as presented. But it would be better to be certain because of the significant implications.
To be certain, we need to find another descendant of William (1826) from another brother, a third independent line to be tested.
If the new test shows a DYS#393 =15, then we can conclude that William (1826) carried a 15 in that location as well. It would be entirely unlikely for both Erasmus’ line and the Brother’s line to have had the same mutation from 14 to 15, meaning that their father must have transmitted a 15 and a mutation from 15->14 occurred in the Elias L. line.
Similarly, if the new test shows a DYS#393 = 14, then it can be concluded that William (1826), the father, carried a 14 and the mutation 14->15 occurred in Erasmus’s line.