DNA Simulation

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Charting Companion features a new tool to help you analyse DNA test results: the DNA Simulation.

(See also DNA Matrix, DNA Matches, video)

The DNA Simulation attempts to place a “graft” into an existing tree. A graft (aka scion) is a person who is seeking his/her biological family. It can be an orphan or an adoptee; it can be a person who was raised by one biological parent, and is searching for the other biological parent. An independent genealogist (“Search Angel”) can do research on behalf of a graft.

Charting Companion will construct a Descendant tree, then will systematically try to link the graft to every person in the tree, one at a time. Charting Companion will calculate the expected centiMorgan (cM) implied by the hypothetical relationship, and compare it to the actual laboratory DNA test results. Each iteration is called a “scenario”. If the DNA test results are outside the cM range, the current scenario is bad, will be discarded, and Charting Companion will advance to the next possible position of the graft in the tree. If the DNA results are consistent, the good scenario will be saved.

The cM values of the relationships are specified in a CSV match file, explained in detail in DNA Matrix.

In addition to linking to existing persons, Charting Companion will also insert hypothetical or placeholder spouses and children, and attempt to link the graft to these additional people. These added persons represent potential extramarital relationships, mistresses, affairs, previous unknown marriages, unknown children, children given up to adoption, non-paternal events, etc. They are meant to suggest possible connections that would otherwise be very time-consuming to evaluate manually.

These hypothetical people are only added in memory and do not affect the genealogical database.

Charting Companion can perform in seconds, analyses that would require hours or weeks if done manually.

For example, John has two sons, David and Charles, and two grandchildren, Susan and James. Adam was an adoptee, and matches Susan at 850 cM (centiMorgans), and James at 700 cM.

Where could Adam fit in the family? Here are some examples of the scenarios automatically generated by Charting Companion:

Adam cannot be a son of David, the cM don’t correlate with being a brother of Susan:

Similarly, Adam cannot be a son of Charles, the cM are incorrect for being brother of James:

Neither can Adam be a half-brother to Susan, assuming that David would have fathered Adam from a different mother:

However, if John and his wife had had another child, and this child had been the father of Adam, the cM would be consistent:

In addition, if John had another child from a different woman, and this child had been the father of Adam, the cM would also fit:

Charting Companion suggests many additional scenarios for this case. Adding dates will significantly reduce the possible options.

Charting Companion will cycle through hundreds and thousands of scenarios, even far-fetched ones, to exhaustively examine all possible solutions, and present you with only the feasible ones, which you can then eliminate with your genealogical knowledge.