STRONG(E)/STRANG(E)/
L'ESTRANGE/ARMSTRONG DNA Project

Most Recent Common Ancestor (MRCA) Marker Analyses

(This page owes a debt of thanks to John A. Blair, DNA Coordinator for the Blair DNA Project; and to Ann Turner, Rootsweb Genealogy-DNA List Administrator)

What the Test Results Tell You
per a discussion by John A. Blair, see: BLAIR DNA Project - Marker Analysis

Based on the most accepted assumptions we derive the Cumulative Probability Table below. This table simply list the number of generations corresponding to the 50%, 90% and 95% probability levels for various numbers of matches.

Match

 


50%


90%


95%

95%
Confidence Interval

12-0

Match exactly at all 12 markers 

14

48

62

1-77

11-1

11 exact matches, 1 mismatch 

37

85

103

5-121

25-0

Match exactly at all 25 markers 

7

23

30

0-37

24-1

24 exact matches, 1 mismatch 

17

40

48

2-57

23-2

23 exact matches, 2 mismatch 

28

56

66

6-75

If all 12 markers match there is a 50% probability that TMRCA is 14 generations or less, a 90% probability that TMRCA is 48 generations or less, and a 95% probability that TMRCA is 62 generations or less. 

If all 25 markers match there is a 50% probability that TMRCA is 7 generations or less, a 90% probability that TMRCA is 20 generations or less, and a 95% probability that TMRCA is 30 generations or less. 

According to John A. Blair, "Although I have no data, I doubt that many groups can trace their surname back more that a 1,000 years. I'm sure there are some than can go back farther, but I would guess they are the exception and not the rule. The Blair surname can be traced back approximately 800 years, to between 1165 and 1200. If you assume 25 years per generation, a 1,000 years is 40 generations. If you use 30 years per generation, a 1,000 years is 33 generations."

Using the above range (33 to 40 generations) and the probability table you can see that a 12 for 12 match means there is less than a 90% probability that the MRCA is within the lifetime of the surname. An 11 for 12 match reduces this probability to approximately 50%. A 25 for 25 match means there is greater than a 95% probability that the MRCA is within the lifetime of the surname. A 24 for 25 match is slightly better that 12 for 12 and a 23 for 25 is somewhat better the 11 for 12.

Ann Turner has written a utility for calculating the MRCA. "The mutation rate is critical for statistical estimates of when the Most Recent Common Ancestor (MRCA) of two people lived. The NUMBER of markers also enters into the calculations. If two people match on all 25 out of 25 markers, that narrows the range of time when the MRCA probably lived, compared to a match on 12 out of 12 markers. ..... I ... wrote a calculator so you can play with the numbers: MRCA Calculator " (Edited from a message posted on the Genealogy-DNA List From: [email protected] (Ann Turner); Subject: Re: [DNA] Marker Choice Comparison; Date: Tue, 2 Apr 2002 22:07:29 EST).

When you use the MRCA calculator http://members.aol.com/dnacousins/MRCA.exe, the results are only calculated for up to two mutations. Any more mutations than that takes you too far into the past to be genealogically interesting.(Edited from a message posted on the Genealogy-DNA List From: [email protected] (Ann Turner); Sent: Monday, April 14, 2003 10:53 AM; Subject: Re: [DNA] mutuation rate chart)

The Mutation Calculator is intended for situations where you know the most recent common ancestor (or you want to do a "what-if" calculation.) In (a) case, you could say, what if "A" and "B" had a common ancestor in the very next generation after the paper trail runs out?

You would have (the cumulative total number of generations between "A" and "B" and the MRCA as the number of) transmission events and enter the typical .002 mutation rate. What's the probability that we would observe 0, 1, 2, 3 or more mutations? Based on the data ... (you can form an opinion as to the number of mutations). ...

...Each new mutation occurs completely at random, independent of any other mutations which have already occurred. The (number of) mutations can be distributed in any way between the two lines.(Edited from a message posted on the Genealogy-DNA List From: [email protected] (Ann Turner); Sent: Monday, April 14, 2003 10:53 AM; Subject: Re: [DNA] mutuation rate chart)

In the end, the thing you're really looking for from the DNA test is the simple indication that "yes, you are related" or "no, you are not related". The more markers you test, the clearer that indication is likely to be, but you would need at least hundreds of markers to get beyond the bare yes-vs-no level. Further, the use of statistics to estimate the probability of a common ancestor becomes less rewarding as you increase the number of markers studied, so there are limitations on the theoretical usefulness of statistics in estimating the number of generations to a Most Recent Common Ancestor.

MRCA Analyses Regarding Oldest Known & Speculative Ancestors
Based on the observations below, it can truely be said that this is an inexact science! The discussion has been limited to cases where there are zero, one, or two marker differences out of 25 markers. The statistical probabilities developed seem at some variance from the actual observations of mutations between given participants in our study, see DNA Results, and insights gained from a study of the documented genealogies of the participants. The observed rate of mutations appears to be somewhat higher than predicted by the statistical projections, even on some markers not rated by Family Tree DNA (FTDNA) as possibly moving more rapidly than others. And, there appears to be a significant possibility of what one DNA Study coordinator has described as "chunk mutations"... situations where the value on a particular marker may have "jumped" in a chunk by two or three steps, rather than just one step at a time. I have a personal suspicion that some of the participants shown as belonging to the respective groupings, but not discussed here because they have 3 or 4 mutations, may very well actually be within the descendancy from the known ancestors discussed here.

Note that the MRCA calculations and predictions discussed below are based on the assumption that the "Assumed Haplotype" indicated in the DNA Results page for each of the lineages discussed is correct. The Assumed Haplotypes are based on an analysis of the marker patterns found for each lineage group in our study where there are at least four participants in a group. Of course this is speculative, and subject to revision on the basis of further findings in the future. Note also, for purposes of applying the Mutation Rate Calculator, I have assumed the individual participant is being compared to a hypothetical contemporary who has descended from the Common Ancestor through the same or similar number of generations but with NO mutations from the ancestral Assumed Haplotype (thus essentially doubling the number of transmission events for a particular participant).

A further limitation on the validity of MRCA analyses is the fact that the mutation rates used in these calculations are based on an assumption that a mutation rate of .002 percent applies. This assumption is known to be at variance from the facts. However, determination of actual mutation rates has yet to be made. Dennis Garvey and others have compiled charts showing Standard Deviation Rates for the various DYS markers used by FTDNA and other genealogical labs, and it is possible to infer the mutation rates from the spread of values found using what is called "proportional analysis".

An example of proportional analysis calculation as applied in our study appears in the discussion regarding the DYS 393 values found in the Donegal & Fermanagh Grouping. However, the use of such calculation is apparently subject to dispute. According to a message from: John F. Chandler to: the GENEALOGY-DNA-List sent: Sunday, April 13, 2003 6:03 PM, subject: Re: [DNA] mutuation rate chart: "The absolute mutation rate cannot be inferred from studies of the variances on individual markers. The proportionality constant can be obtained by assuming a standard average mutation rate, of course, but the basic assumption behind variance studies is that there is no drift going on in the time period since a particular haplogroup began, and that assumption is clearly wrong. The time scale of drift is the same as the time scale of haplogroup formation."

Dr. David L. Roper has developed a table of mutation rates for various DYS markers based on the use of proportional analysis in his webpage "Y-Chromosome Markers for Many Families"; see his discussion on Variability of Markers, and note his caveat "Of course, the important question in this calculation is whether the average mutation rate of 0.2% is correct." In the future, we may be able to apply his analysis to particular cases in our study. For now, however, the presentation below assumes fixed mutation rates of .2%=1/500 for each of the 25 markers. For purposes of applying the Mutation Rate Calculator, I have assumed the individual participant is being compared to a hypothetical contemporary who has descended from the Common Ancestor through the same number of generations but with NO mutations from the Assumed Ancestral Haplotype.

Personally, based on an evaluation of the differences between the statistically predicted results and the actual results, and at least until better determination can be made of actual mutation rates for the various DYS markers, I would be more inclined to go with "informed hunches" about the number of generations to a MRCA based on paper research than based on the statistical predictions. The best it can be said about the statistical predictions is that they MAY give some insights which MIGHT be useful to an informed researcher. The reader will note that I have made a "Guess" as to the expected number of generations between a participant and a speculative ancestor. That is exactly what the number is, and I am willing to accept further imput from the researchers of the lineages involved to modify such guesses. I think in many cases they are more qualified than a statistician to make such informed hunches, or guesses, based on their own knowledge of the research background. To the extent that the MRCA calculations here may be of assistance, they are offered for the use and enjoyment of interested researchers.



Group New England

Known Ancestor #K001: "Elder"John Strong, of Massachusetts


Birth:   1605 Taunton, Somersetshire, England
Marriages:   #1: before 1634 Margery Deane
#2: about 1635Abigail Ford
Death:   16 April 1699Northampton, Hampshire, Massachusetts
  Wife #1: Margery Deane
Birth:   Abt 1610
Death:  about 1635 Massachusetts
  Wife #2: Abigail Ford
Birth:   before 8 Oct. 1619Bridport, Dorset, England
Death:   16 July 1688Northampton, Massachusetts

Participant Kit# 6811:

  Descendant of John Strong, Jr, son #1 of: "Elder"John Strong, of Massachusetts (and his first wife, Eleanor Deane)
  Remarks: See Chart #6811 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the assumed "Elder John" or "New England" Strong Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant: 10
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 20
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: Assumed to be one, eg., 1 step on DYS 464d=> (20-19=1)
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 1
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator):.36788
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ): If only 24 of 25 markers match there is a 50% probability that TMRCA is 17 generations or less, a 90% probability that TMRCA is 40 generations or less, and a 95% probability that TMRCA is 48 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 10

Participant Kit# 7257:

  Descendant of Jedidiah Strong, son #4 of: "Elder"John Strong, of Massachusetts (and his second wife, Abigale Forde)
  Remarks: See Chart #7257 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the assumed "Elder John" or "New England" Strong Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant: 10
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 20
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: Assumed to be one, eg., 1 step on DYS 449=> (30-29=1)
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 1
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator):.36788
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ): If only 24 of 25 markers match there is a 50% probability that TMRCA is 17 generations or less, a 90% probability that TMRCA is 40 generations or less, and a 95% probability that TMRCA is 48 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 10

Speculative Ancestor #S001: "Elder"John Strong, of Massachusetts
Details:   As Above for Known Ancestor #K001: "Elder"John Strong, of Massachusetts

Participant Kit# 5858:

  Speculative Descendant of Unknown Strong, son#___ of: "Elder"John Strong, of Massachusetts
  Remarks: See Chart #5858 & Note #3 for Existing Documentation. For purposes of this discussion, the participant in Kit #5858 could be a descendant of either John, Jr; Jedidiah; or another son of Elder John Strong. The results of DNA Testing show a pattern of markers characteristic of the assumed "Elder John" or "New England" Strong Haplotype.
  Number of Generations (Transmission Events) between Speculative Ancestor and Present Generation Participant: Assumed to be 10
Total Number of Transmission Events between Assumed Ancestor and Present Generation Participants: Assumed to be 20
Actual Total Number of Observed Mutations between Speculative Ancestor and Present Generation Participants: Assumed to be one, eg., 1 step on DYS 447=> (26-25=1)
Expected Number of Probable Mutations between Speculative Ancestor and Present Generation Participants (using Mutation Rate Calculator): 1
Probability of Observed Number of Mutations between Speculative Ancestor and Present Generation Participants (using Mutation Rate Calculator):.36788
Probable Number of Generations between Speculative Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ): If only 24 of 25 markers match there is a 50% probability that TMRCA is 17 generations or less, a 90% probability that TMRCA is 40 generations or less, and a 95% probability that TMRCA is 48 generations or less.
Guess as to Actual Number of Generations between Speculative Ancestor and Present Generation Participants: Probably 10, +/- 2


Group Southern

Known Ancestor #K002: John Strong, of New Kent County, Virginia


Birth:  c.~1650-1660 England
Marriage:   before 1697wife's name unknown
Death:   after 1703Virginia
  unknown Wife
Birth:   unknown
Death:  after 1703 Virginia

Participant Kit# 8314:

  Descendant of John Strong, Jr, son #1 of: John Strong, of New Kent County, Virginia
  Remarks: See Chart #8314 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the assumed John Strong of New Kent County, Virginia Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant: 10
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 20
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: Assumed to be one, eg., 1 step on DYS 447=> (26-25=1)
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 1
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): .36788
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ):If only 24 of 25 markers match there is a 50% probability that TMRCA is 17 generations or less, a 90% probability that TMRCA is 40 generations or less, and a 95% probability that TMRCA is 48 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 10

Participant Kit# 5834:

  Descendant of William Strong, son #2 of: John Strong, of New Kent County, Virginia
  Remarks: See Chart #5834 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the assumed John Strong of New Kent County, Virginia Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant: 9
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 19
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: Assumed to be two, eg., 1 step on DYS 447=> (26-25=1); and 1 step on DYS 385a=> (11-10=1)
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 1
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator):.18394
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ):If only 23 of 25 markers match there is a 50% probability that TMRCA is 28 generations or less, a 90% probability that TMRCA is 56 generations or less, and a 95% probability that TMRCA is 66 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 9

Participant Kit# 6663:

  Descendant of William Strong, son #2 of: John Strong, of New Kent County, Virginia
  Remarks: See Chart #6663 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the assumed John Strong of New Kent County, Virginia Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant:10
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 20
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: Assumed to be two, eg., 1 step on DYS 458=> (17-16=1); and 1 step on DYS 455=> (12-11=1)
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 1
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator):.18394
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ):If only 23 of 25 markers match there is a 50% probability that TMRCA is 28 generations or less, a 90% probability that TMRCA is 56 generations or less, and a 95% probability that TMRCA is 66 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 10


Group Donegal Bay

Known Ancestor #K003: Hugh Strong, of County Donegal, Ireland and Brighton, Ontario, Canada


Birth:  c.1830 County Donegal, Ireland
Marriage:   April 8, 1856Sarah White
Death:   January 1919Brighton Twp, Ontario, Canada
  Sarah White
Birth:   November 13, 1838 Prince Edward County, Upper Canada, (now Ontario), Canada
Death:  May 28, 1907 Brighton Twp, Ontario, Canada

Participant Kit# 6761:

  Descendant of William Thomas Strong, son #1 of: Hugh Strong, of Brighton Twp, Ontario, Canada
  Remarks: See Chart #6761 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the Assumed Donegal Bay Strong Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant: 4
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 8
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: None
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 0.4
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): .67032
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ):If all 25 markers match there is a 50% probability that TMRCA is 7 generations or less, a 90% probability that TMRCA is 20 generations or less, and a 95% probability that TMRCA is 30 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 4

Participant Kit# 8431:

  Descendant of William Thomas Strong, son #1 of: Hugh Strong, of Brighton Twp, Ontario, Canada
  Remarks: See Chart #8431 for Existing Documentation. The results of DNA Testing show a pattern of markers characteristic of the Assumed Donegal Bay Strong Haplotype.
  Number of Generations (Transmission Events) between Known Ancestor and Present Generation Participant: 3
Total Number of Transmission Events between Known Ancestor and Present Generation Participants: 6
Actual Total Number of Observed Mutations between Known Ancestor and Present Generation Participants: None
Expected Number of Probable Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): 0.3
Probability of Observed Number of Mutations between Known Ancestor and Present Generation Participants (using Mutation Rate Calculator): .74082
Probable Number of Generations between Known Ancestor and Present Generation Participants (using John A. Blair's Cumulative Probability Table which was apparently developed from calculations such as those produced by the MRCA Calculator ):If all 25 markers match there is a 50% probability that TMRCA is 7 generations or less, a 90% probability that TMRCA is 20 generations or less, and a 95% probability that TMRCA is 30 generations or less.
Actual Number of Generations between Known Ancestor and Present Generation Participants: 3



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Most Recent Common Ancestor (MRCA) Analyses


Go to Researching Strong(e)s & Strang(e)s in Britain and Ireland

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Please let us know if this webpage has been helpful! We would very much appreciate being advised of any possible additions or corrections. Email: David B. Strong; or contact me through the Rootsweb Strong-List.�� This webpage was: Created Wednesday, April 16, 2003 4:30 PM. Last Updated: Wednesday, May 14, 2003 - 6:22 PM

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