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As promised, I took a stab at aging the SNP blocks under Z16357. You can view the updated SNP chart with ages at? (you may need to hit Refresh to see the updates).

These are very rough estimates. The first date listed for each block is an estimate of the "formed date" - when the first SNP in that block was formed. The second date is a Time of Most Recent Common Ancestor (TMRCA) date - meaning when the last SNP in that block was formed, or the nearest date that two testers in child branches might expect to share a common ancestor in that block. We can't know which SNP in the block is oldest and which is newest or where within that date range common ancestors are actually shared (at least without additional documentation or testing).

Z16357 has several TMRCA estimates. YFull and SNP Tracker estimate it as?, Ytree (based on?Iain McDonald's work) has it as?, and Dave Vance (one of the L513 administrators) has it as . So that's 1000+ years difference between estimates. For broader range estimates, it's better to assume an older age.

Our 28 known testers have an average of 55 variants at or below Z16357 - a high of 67 and low of 45 (st. dev. of 5.7). Much of this variability is due to higher variant count coverage/possibilities for Big-Y 700 testers vs. Big-Y 500 testers - I didn't provide any factoring/weighting for the different test types (I'm not certain who has which test type anyway).

I also did not consider STR differences - which could provide some insight into larger blocks. For example, if an SNP block spans hundreds of years, STR differences could give insight into whether the MRCA is at the beginning or end of that time span.?I did, however, make some minor adjustments in time spans for the few known common ancestors we have across testers.

With a formed age estimate of 3900 years ago, this comes out to 71 years per SNP - well faster than the generally-accepted 83.3 value used on many aging calculations. I'm using FTDNA's average aggregated private variants for each terminal block (rather than exact private variant values). With this 71 years value, I then stepped backward from 1950AD to 1950BC (the 3900 year span) to assign date estimates for each block.

You can review my spreadsheet for the calculations at The spreadsheet also provides TMRCA estimates if Z16357 instead has formed dates of 3500 years ago (63.7 years per SNP) or 3000 years ago (54.6 years per SNP). These differences are relatively minor for more recent haplogroups, but become quite significant for older haplogroups.

One item of note is the significant time distance between the two sides of the Z16357 tree - Z16343 and BY19970 split probably 3000+ years ago and then each had 2000+ years with no (yet) known branches - which is primarily why most of my research analyzes these in isolation from each other.

I'd be VERY happy to have feedback or criticism on my methodologies or the dates estimated. I'll update these estimates any time we have a notable update to the tree.

Cheers,

Jared