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smithsworldwide (Admin)
The YSAPP chart on the groups pages on

Posted by smithsworldwide in Smith DNA on March 8, 2023 Views:(27Replies (0)
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Dave Vance wrote a program called SAPP, which we use to create Y-DNA trees based on the STR markers of those who FamilyTreeDNA has already determined to match within a given group.  The chart is not infallible; however, the author has based his methodology thusly 

The Smith DNA Project relies on those who have sent in tree lines, attempts to verify the line as much as possible, but also welcomes those who have suggestions or corrections to lines. (Why we have suggest buttons or contact us on most pages on this site). Particularly for SAPP, the inputs for creating the chart put people together who have a common known proven ancestor under a given *node* while the "Group MRCA" shows the time to the sometimes known, sometimes not, Most Common Ancestor of the group. If a given member's line cannot be proven to an earlier ancestor, even where they match according to FTDNA, the SAPP chart will show them not as under an earlier ancestor but in a separate node, with the STR marker variances on each person. Repeating that this still shows that they match within the group, we just do not know how exactly.

The SAPP charts use text file inputs to create the chart, from the FTDNA YDNA chart for the Smith DNA Project.  This is why you will see, on most charts, a date, ie Last Updated XXXX date. When a new member joins and fits into a given group, the SAPP chart is updated at that point and a new date put on the chart.

FamliyTreeDNA does not send notices to surname project admins when a SNP is refined or changed, or a new tester matches a private variant in another kit. Therefore, if you see something that looks like it needs updating, send a message to so we can take a look, and fix it.

As always, keep in mind that surname projects on FTDNA are run by volunteers and again, rely on members nofifying the admins if, say, new information on their tree comes out, SNP number has been refined, or some other aspect needs to be corrected, fixed or added.