McAninch TMRCA (Time to Most-Recent Common Ancestor) Calculations

Three McAninch males living in the 21st-century have taken Y-DNA tests at Family Tree DNA:

a. this author, sixth-generation descendant of Kentucky pioneer Daniel McAninch (b.1750-1755,

    (northern) Ireland,, prob. Tennessee) [Daniel McAninch, 1.a. above, and Note n4]

b. a sixth-generation descendant of Kentucky pioneer William McAninch (b.bef.1765, d.1813,

    left his Will in Casey County, Kentucky) [William McAninch, 1.b. above, and Note n4]

c. a seventh-generation descendant of John McAninch, western Penn., Armstrong County pioneer

    (, (Scotch Corners) Ireland,, Buffalo Twp., Armstrong County, Penn.,

    father of ‘three brothers’ William, John, and Henry in Pennsylvania) [2.a. above, and Note n5]

The TMRCA Calculations were run online at Family Tree DNA, using their ‘TiP’ method [51]

(Infinite Allele Method) [36]. With 6 and 7 generations born in North America, we know there

were no common ancestors in those generations, and any possible MRCA (Most-Recent Common

Ancestor(s)) would almost certainly have lived in the British Isles (probably in northern Ireland).

So, comparing the Y-DNA results with each other McAninch, knowing that we did not have a

common ancestor in the last 6 or 7 generations, the probability that we shared a common ancestor

within the last ‘n’ generations (beyond 6 or 7) generated the following distribution [52]:

 8 Generations: 25.0% - 34.41% (range of probabilities from TiP’s among three McAninch men)

12 Generations:             65.28% - 72.91%

16 Generations:                           86.55% - 91.27%

20 Generations:                                         95.37% - 97.61% (96.5% mean, range ~2.2%)

24 Generations:                                                       98.53% - 99.42% (98.9% mean, range 0.9%)

Now, converting ‘generations’ into ‘years’ (using 33 years per male generation) [53] [54],

expanding the range by +/-15% (which will account for assumed mutation rates, etc.) [55] [56],

and based on ‘years before present’ (ybp) before 1950 [57], we get these two TMRCA ranges:

  20 generations TMRCA est. 667 ybp (1950), +/- 100 yrs (15%), range 1180-1385 CE [58], and

  24 generations TMRCA est. 800 ybp (1950), +/- 120 yrs (15%), range 1030-1270 CE [59].

So, 98.9% at 24 generations gives a very high probability for a Most-Recent Common Ancestor

(MRCA) back in the 11th or 12th Century, long before surnames or international borders, and

long before any written records or ‘paper trail’ that might identify or trace our common ancestor.

Larger (11-man) TMRCA (Time to Most-Recent Common Ancestor) Calculations

Larger focus group: combining Y-DNA data available in the R1b-M222 Project [22] and in the

Clan MacInnes DNA Project [n2] (both projects are hosted by Family Tree DNA) with some

additional data provided in private correspondence, there are 11 men in our experimental larger

focus group for another Time to Most-Recent Common Ancestor (TMRCA) calculation [60]:


McAninch Y-DNA Status Report 2016: 7 of 8: Time to Most-Recent Common Ancestor calc’s

McAninch Family History NL v.XXIV n.1 / April 2016 / Copyright Frank McAninch / pg.2016-08

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