Analysis. Coker YDNA comparison, Kit C-12

The following data was generated by yONE, a program currently in Beta development. This program compares YDNA data for a specific Kit with other Kits for persons sharing the same surname. The results presented here are for discussion purposes only, and are to be used to illustrate how yONE output can be used to evaluate family relations. These data may be revised during the course of program testing.

Data

The data used for this analysis were prepared by Beth Gay, and were derived from multiple YDNA service provider sources, including FTDNA, and Ancestry. The data is too voluminous for ready inclusion on this site, but is available for examination from User:Beth, or User:Quolla6.

Explanation

yONE compares YDNA data for a specific Kit, with other kits available for the same surname. In the present instance, Kit C-12 was compared to each of 21 other kits. The above table provides 6 data elements for each yDNA kit evaluated:

• Kit number
• Lineage data (such as is available)
• Haplogroup
• Number of Markers evaluated (the lesser of the number of markers for the kit being tested, and that of the kit against which it is being compared.)
• SimDif: a DisSimilarity Index, showing how dissimilar one kit is compared to another, based on whether any given marker in the kit being considered (C-12, in this case) is the same or different from the marker of kit to which it is being compared.
• SimStep: a DisSimilarity Index based on the "StepWise" modal used in YDNA studies. SimStep counts the differenec between the markers, not just a simple "same versus different" evaluation used in the SimDif Index.

As a generalization, a SimDif value of about 10% or less indicates that two kits share a relatively recent common ancestor. This would be the equivalent a test result that would be

• 7-off out of 67 markers,
• 4-off out of 37 markers,
• 3-off out of 25 markers,
• 1-off out of 12 markers.

Because the comparisons are expressed as a percentage, it is possible to directly compare results from two kits, even when the number of markers in each kit differ from each other. This greatly simplifies the comparison of multiple kits.

Output

Discussion

This yONE run compares the KIt C-12 with each of the other Coker kits available. Kit C-12 is from a descendant of a James Coker of Alabama (c. 1764-1834). Four other kit results compare favorably with C-12: C-16, CA-X, C-15, and C-4. Each of these other kits trace to a different KNOWN ancestor. CA-16 is most similar with a SimDif Index of 0% (meaning it shares exactly the same markers as C-12). The other three kits are progressively more dissimilar to C-12, with C-4 lying at the edge of the range of index values (12%) that could be considered to have a relatively recent common ancestor.

The five kits shown in the table highlighted in green probably share a relatively recent common ancestor. Without knowing more about their genealogy than is immediately available, we can't say a great deal about who that common ancestor might be. Since C12 and C-4 are almost exact contemporaries of each other (one born 1764, the other in 1757), we can conclude that their common ancestor lived at least one or two generations previous to them. What we know with reasonable certainty is that all five of these kits share a common ancestor in the relatively recent past---probably someone born no later than about 1730 or so, but possibly several generations prior to this. By looking closely at the genealogical history of the five individuals associated with these kits, it may be possible to find common connections that may help shape and define the course of future research.

Graphics

The adjacent diagram graphically illustrates the results of the yONE run comparing Coker Kit C-12 with all other Coker kits. The area circled in red highlights those kits whose SimDif Index (Dissimilarity Index) is 12% or less. Overall, a dissimilarity of ABOUT ten percent or more indicates a lack of a relatively recent common ancestor in a genealogically meaningful timeframe. Kit C-4, for a descendant of Simeon Coker of South Carolina, b. 1818, lies at the edge of the acceptance criteria, and his common ancestor with C-12 for a descedant of James Coker of Alabama, probably lies further back in time than that for the other kits with lower dissimilarity indexes.

Interpretation

The yONE run for the C-12 Kit, shows that the C-12 Descendant shared a relatively recent common ancestor with four other individuals who also took the yDNA test, and used the Coker surname: C-16, C-X, C-15, and C-4. Each of the descendants corresponding to these kits identifies a different individual as their earliest known ancestor. Assuming that these descendants have described their lineages correctly, we can assume that their common ancestor lies somewhat further back than 1756 (the earliest DOB for the earliest known ancestor among the five descendants).

There are several possible interpretations of the relationships between these individuals. The simplest interpretation is that they all descend independently from their common ancestor. This would be the case if, for example, their common ancestor had five sons, and each of the descendants, descended from one of those five sons. This might be referred to as fitting an "Indepependent Descent Model", as shown below.

At the other extreme is the Dependent Descent Model, where each descendant represented by the various kits, share substantial portions of their ancestry with each other subequent to their single common ancestor. This would be the case, for example, if the common ancestor had a single son, who gave rise to a chain of successive male descendants culminating in the C-12 descendant. In this interpretation, the other Kits that show a common ancestry with C-12 would arise from different male descendants along the chain leading to C-12, as shown below:

The above two models represent the two extremes of the possible lines of descent of the five individuals whose YDNA results show that they have a relatively recent common ancestor. There are many indpendent variations between these two extremes that could also explain the results obtained. For example, the common ancestor might have had two sons, each of which gave rise to one or more lineages resulting in the suite of descendants represented in these YDNA results. It will be the challenge of the descendants to find their exact lines of descent, showing how they inter-relate with each other. This is no less challenging a task than traditional genealogy presents. The advantage that YDNA results such as these give the individuals is that they now know that they are mutually related in some complex (or simple) manner, and that by sharing their combined knowledge they may be able to find their common heritage.