To understand his Y-chromosome DNA first you need a little background.

 

 

The dna signature of Samuel Finger (his "haplotype" displayed below) places him in the most common European Haplogroup - Haplogroup R1b.  See http://en.wikipedia.org/wiki/Haplogroup_R1b

 

Haplogroups are dna clans.  For male Y-chromosome tests, haplogroups are defined by a kind of marker called an SNP (Single Nucleotide Polymorphism). 

 

But surname dna testing is performed on another kind of marker called an STR (Short Tandem Repeat), because they mutate more rapidly than SNPs, in a time frame that includes the adoption of surnames by most people on Earth.  SNPs are good for deep time relationships.  STRs are good for recent time relationships.

 

It so happens that the haplogroups defined by SNPs are very closely correlated to patterns of STRs.  So knowing the STR haplotype allows one to predict the haplogroup with a high degree of certainty.

 

Samuel's dna signature was obtained from two of his descendants in 2008, 440 years after his birth.  A cotton swab of the cheek inside the mouth provides cells used for analysis. 

 

The STR markers on the Y-chromosome, called Y-STRs, are passed down from father to son to grandson without any contribution from their mothers.  About once in every 500 births there is a mutation, on average.

 

Samuel's male descendants have his Y-STRs, with the possibility of an occasional mutation.

 

STRs, as their name implies, are repeats of a particular sequence (a Short Tandem).  The number associated with each STR is the number of repeats.  About once in every 500 births, there is an increase or a decrease in the number of repeats.  Increases are favored over decreases, otherwise STRs would disappear!

 

Individuals are compared by the number of exact matches and the number of mismatches (and the magnitude of the mismatches, one count or two counts, etc.).  Multiple STRs are tested to increase the number of likely mutations.  We tested 43 Y-STR markers.  If each of 43 STR markers has an average mutation rate of 1 in 500 births, then 43 of them have a likelihood for mutation of 43 in 500 births, or about 1 mutation in 11.6 births.

 

names of the Y-STR markers:

DYS19 DYS385a DYS385b DYS388 DYS389i DYS389ii DYS390 DYS391 DYS392 DYS393 DYS426 DYS437 DYS438 DYS439 DYS441 DYS442 DYS444 DYS445 DYS446 DYS447 DYS448 DYS449 DYS452 DYS454 DYS455 DYS456 DYS458 DYS459a DYS459b DYS460 DYS461 DYS462 DYS463 DYS464a DYS464b DYS464c DYS464d DYS635 GATAA10 GATAH4.1 GGAAT1B07 YCAIIa YCAIIb

one result:

14 11 15 12 13 29 24 11 13 12 12 15 12 12 14 17 12 13 13 25 19 31 30 11 11 16 16 9 10 11 13 12 24 13 15 17 17 23 13 22 10 19 24

other result:

14 11 15 12 13 29 24 11 13 12 12 15 12 12 14 17 12 13 13 25 19 31 30 11 11 16 16 9 10 11 12 12 24 13 15 17 17 23 13 22 10 19 23

 

 

The two individuals tested are tenth cousins, once removed, of Samuel's son Johann Jost, born in Bottendorf about 1610 - the first Finger born there. 

 

One of them is the 10th direct male descendant of Johann and the other is the 11th direct male descendant.  They are separated by 21 births - 21 opportunities for a mutation.  And with an average rate of 1 mutation in 11.6 births, and 21 opportunities, that's 1.8 mutations.  Since we can't have a fractional mutation we would expect one or two mutations.  Lo and behold, that's exactly what we see - two mutations! 

 

Marker DYS461 is 13 for one and 12 for the other.  Marker YCAIIb is 24 for one and 23 for the other.

 

We can only answer this question probabilistically.  Usually markers increase their number of repeats, but they can also decrease.  The likelihood of increasing slightly outweighs the likelihood of decreasing, so the best answer we can give is that Samuel probably had the lower value on the two different markers.

 

The companies that perform genealogical dna testing have found that in 2% to 5% of cases, known cousins don't match.  This is due to secret adoptions or secret paternity.  Families sometimes choose to keep such things secret.  So it's important to have more than one descendant to establish the ancestor's dna.

 

Furthermore, it's important to have cousins as widely separated as possible.

 

What we really have is Johann Jost Finger's dna.  We only have Samuel's dna if Johann Jost was his true son.  We have no reason to believe otherwise, but to be absolutely certain we would need dna from a descendant of one of Samuel's other sons.  That's what we will look for next.

 

We can now compare dna signatures from other men named Finger and know with a degree of certainty whether they are closely relate, distantly related, or not related at all (for practical purposes) to Samuel Finger.

 

We can compare Samuel's signature to know Modal Haplotypes, like the Atlantic Modal Haplotype.  There is one single-count differences from the Atlantic Modal Haplotype (AMH), with consists of 6 Y-STR markers.  Samuel is close, but not exactly in AMH.  That difference places him in AMH 1.15+, also referred to as the Atlantic Modal Cluster.  See http://en.wikipedia.org/wiki/Atlantic_Modal_Haplotype

 

We can compare Samuel's signature to the Cohen Modal Haplotype, a sequence of 12 Y-STR markers that is statistically more common in Jewish males with the name Cohen, or its derivative, than in Jewish males with some other name.  The Kohanim (Cohen) held special priestly offices in the Temple in Jerusalem.  See http://en.wikipedia.org/wiki/Y-chromosomal_Aaron

 

Samuel differs in 7 of the 12 markers in the CMH, some by more than one count.  Samuel does not belong to the Cohen Modal Haplotype.  No all Cohens are members of CMH, and many non-Jewish men have dna signatures that exactly match CMH.  So we cannot say anything definitive.  Such is the nature of probability.

 

We can compare Samuel's signature to a typical Samaritan haplotype.  The Samaritans are an ancient people, fewer than 1,000 souls today, that claim to be the true followers of the religion of the Israelites, predating the Jewish Temple in Jerusalem.  They base their religion on the Torah, but do not call themselves Jews.  Samuel has 7 of 12 markers different from the typical Samaritan haplotype, some by more than one count.  Samuel is almost certainly not a Samaritan.  See http://en.wikipedia.org/wiki/Samaritan

 

If we did not know that Tom and Fred were tenth cousins once removed, we could make a guess as to their Last Common Ancestor (LCA), also called their Most Recent Common Ancestor (MRCA) in other references. 

 

This is based upon the average rate of mutation, 1 in 500, and a particular mathematical model.  (I have used the 'infinite alleles' model.) 

 

Using this method and 43 Y-STR markers with two different, and knowing nothing else about their relatedness, we could say that Tom and Fred had a 50% chance of a LCA in 16 generations or less, 90% chance of a LCA in 31 generations or less, and 95% chance of a LCA in 37 generations or less.

 

We know from paper records that Tom and Fred have their LCA 10.5 generations ago.  So you can compare that knowledge to the statistical probability.

 

The paper records run out, for common people, about 1600 in this part of Germany.  It was fortuitous that Tom and Fred are related just one generation after the beginning of the paper trail.

 

Contrast that with the probabilities if Tom and Fred had all 43 markers matching perfectly: 50% chance of LCA in 4 generations or less, 90% chance of LCA in 13 generations or less, 95% chance of LCA in 17 generations or less.

 

Those two different markers make a big difference in the probabilities.  Happily, we have paper records and don't have to relay on probability.

 

You can see how paper records are so very important, more so than probabilities.  When the paper trail runs out, all you have is DNA!