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Nqp15hhu
05-17-2020, 09:35 PM
I am waiting on my Big Y results, but I have tested as R1B-A7713 which is downstream of:

R1BA7711>By2634>by651>l193.

When I map A7713 it appears as being Northern Irish, which his true. My paternal line is a planter line that came here from Scotland.

However, I am not understanding why there is only one snp between the migration and now? A7713 is supposed to cover 500 years. Is that accurate?

Why would there not be a snp between the Plantation and now, especially considering there has been a second migration to the United States in our branch. Why would a man in North Carolina who isnít related to me within 300 years share the same SNP as me?

When and why does a new SNP form?

Can I not use this SNP to find a point of origin for my ancestors?
Iím confused!!

Webb
05-18-2020, 01:17 PM
I am waiting on my Big Y results, but I have tested as R1B-A7713 which is downstream of:

R1BA7711>By2634>by651>l193.

When I map A7713 it appears as being Northern Irish, which his true. My paternal line is a planter line that came here from Scotland.

However, I am not understanding why there is only one snp between the migration and now? A7713 is supposed to cover 500 years. Is that accurate?

Why would there not be a snp between the Plantation and now, especially considering there has been a second migration to the United States in our branch. Why would a man in North Carolina who isn’t related to me within 300 years share the same SNP as me?

When and why does a new SNP form?

Can I not use this SNP to find a point of origin for my ancestors?
I’m confused!!

When it comes to very downstream snp's, it unfortunately "takes two to tango", so to speak. I guarantee that you have private snp's that are not reported. These snp's remain filed in FTDNA's database and will stay that way until someone else tests positive for one of your private snp's. I will use myself as an example. For a very long time I was FGC23196. Then one of my 111 marker matches upgraded to the Big Y test. I only know because my terminal snp changed out of the blue to FGC33002. This match is a 111 marker step 9 match. I have other 111 marker matches but they are steps 4 and 8. If one of these closer matches were to upgrade to the Big Y test, my terminal snp would probably change again. According to FTDNA's TiP report my match whom I share FGC33002 and I haven't had a common ancestor since 1200 AD. The other closer matches are around 1400AD. The two closer matches are Wilder, the FGC33002 match is Shields from Ireland, and then myself, Webb.

Nqp15hhu
05-18-2020, 01:47 PM
So A7713 isnít my full snp then? Interesting.

Dave-V
05-18-2020, 05:07 PM
When you look at the current FTDNA "Block Tree" view for this part of the haplotree, you get the first picture shown here.

37644

R-A7713 is listed as one SNP within the equivalent block on the left hand side of this picture that is currently called "R-A7711". For each block they pick one SNP (essentially at random although there are a few criteria) as the name/label for the block, although new testers can "break up" existing blocks as they form new branches of the haplotree.

Each block of SNPs on the Block Tree represents an unbroken (so far) line of male ancestors of enough generations that that number of SNPs was able to form. On average based on Big Y-700 testing SNPs will form about every 84 years, although there is a large variance in that rate so it's hard to gauge ages of past ancestors based on small numbers of testers or over short periods of time. Within each block the SNPs that have been discovered so far that formed along those generations are listed but we don't really know what order they occurred in so the order they're listed in isn't really meaningful. One of the SNPs in each block happened first in that span of time and one of the SNPs happened last, but we don't yet know the order.

If I take the Block Tree view and try to translate it to its male ancestral tree I get this picture here. For simplicity I have focused on the line that includes A7713 and not shown all the descendant branches from the picture above that formed on the lines descending from the R-FT82593 SNP.

37645

All I'm trying to do is show what the Block Tree represents as far as male ancestry, with the ages in green estimated based on the number of SNPs across all the lines. I'm assuming by the way that all the kits in these branches were tested for Big Y-700 which is probably a big assumption; if there were Y-500s in the mix that would change these estimates somewhat. Also PLEASE bear in mind that the estimates have a large error range anyway so certainly for example the split at the end of the R-A7711 block into the three current testers could certainly have happened earlier than 1750AD, even as early as 1600AD if the average of 2 SNPs in their private lines was mostly from Y-500 testing or their mutations were on average much less frequent than the statistical norm. So take that picture and those dates as representative, not firm.

However it tells me at least a few things - first off, if your Big Y results place you under the R-A7711 block then anyone related to you along the OTHER branches doesn't share a common (paternal) ancestor with you from Plantation times down to present day if the estimate of 1050AD for the start of the R-A7711 block is anywhere close to accurate. The start of the R-A7711 block is at best "early medieval" in timeframe.

The second thing it suggests is that when your Big Y results DO come in, it may split apart the 15 SNPs in the A7711 block into two blocks since you may be negative for some of them. That just means your common ancestor with the other three men under the R-A7711 block is likely to be older than the common ancestor of those three men so you would form a new branch under most but not all of the SNPs from that current R-A7711 block. That remains to be seen since my estimate of 1750AD may be off for a number of reasons and so you may not break up the block at all.

Nqp15hhu
05-22-2020, 10:57 PM
When you look at the current FTDNA "Block Tree" view for this part of the haplotree, you get the first picture shown here.

37644

R-A7713 is listed as one SNP within the equivalent block on the left hand side of this picture that is currently called "R-A7711". For each block they pick one SNP (essentially at random although there are a few criteria) as the name/label for the block, although new testers can "break up" existing blocks as they form new branches of the haplotree.

Each block of SNPs on the Block Tree represents an unbroken (so far) line of male ancestors of enough generations that that number of SNPs was able to form. On average based on Big Y-700 testing SNPs will form about every 84 years, although there is a large variance in that rate so it's hard to gauge ages of past ancestors based on small numbers of testers or over short periods of time. Within each block the SNPs that have been discovered so far that formed along those generations are listed but we don't really know what order they occurred in so the order they're listed in isn't really meaningful. One of the SNPs in each block happened first in that span of time and one of the SNPs happened last, but we don't yet know the order.

If I take the Block Tree view and try to translate it to its male ancestral tree I get this picture here. For simplicity I have focused on the line that includes A7713 and not shown all the descendant branches from the picture above that formed on the lines descending from the R-FT82593 SNP.

37645

All I'm trying to do is show what the Block Tree represents as far as male ancestry, with the ages in green estimated based on the number of SNPs across all the lines. I'm assuming by the way that all the kits in these branches were tested for Big Y-700 which is probably a big assumption; if there were Y-500s in the mix that would change these estimates somewhat. Also PLEASE bear in mind that the estimates have a large error range anyway so certainly for example the split at the end of the R-A7711 block into the three current testers could certainly have happened earlier than 1750AD, even as early as 1600AD if the average of 2 SNPs in their private lines was mostly from Y-500 testing or their mutations were on average much less frequent than the statistical norm. So take that picture and those dates as representative, not firm.

However it tells me at least a few things - first off, if your Big Y results place you under the R-A7711 block then anyone related to you along the OTHER branches doesn't share a common (paternal) ancestor with you from Plantation times down to present day if the estimate of 1050AD for the start of the R-A7711 block is anywhere close to accurate. The start of the R-A7711 block is at best "early medieval" in timeframe.

The second thing it suggests is that when your Big Y results DO come in, it may split apart the 15 SNPs in the A7711 block into two blocks since you may be negative for some of them. That just means your common ancestor with the other three men under the R-A7711 block is likely to be older than the common ancestor of those three men so you would form a new branch under most but not all of the SNPs from that current R-A7711 block. That remains to be seen since my estimate of 1750AD may be off for a number of reasons and so you may not break up the block at all.

Hi Dave. Thanks for answering this. You say that I may 'break up' the A7711 block, does this happen with all matches and is it likely? Do we each earn our own private SNP or will I be placed in with another shared SNP further downstream from A7711?

When you refer to the formation of a new SNP at 84 years, is that a specified time period or based on two generations within the male line i.e from Grandfather to son?

So, my interpretation of your graph is that the A7711 block is my current block, that formed in the 11th century. Does this then mean that my SNP for now is just a 'basic' SNP and there should be a value beyond that i.e for 1800's? I had assumed that SNPS dated back a 100 years or so, I didn't consider the possibility of only being able to date as close as 1200 AD etc.

TigerMW
05-24-2020, 02:42 PM
... I may 'break up' the A7711 block, does this happen with all matches and is it likely?

No, every area of the tree is a different circumstance which different potential testers getting engaged and each branch having varying numbers of equivalent SNPs. I don't think we can generally say a new test result will generally break up a block or not.


Do we each earn our own private SNP or will I be placed in with another shared SNP further downstream from A7711?
Unless someone very closely related, like a brother or father, is testing you are likely to have a private SNP or multiple private SNPs. The reason is the estimated average you cited of an SNP every 80 years or so.


When you refer to the formation of a new SNP at 84 years, is that a specified time period or based on two generations within the male line i.e from Grandfather to son?
This is not specifically tied to number of generations. There are reports that SNPs are common in father-son transmissions when fathers are older so you can't really look at this as an average by generation.


So, my interpretation of your graph is that the A7711 block is my current block, that formed in the 11th century. Does this then mean that my SNP for now is just a 'basic' SNP and there should be a value beyond that i.e for 1800's? I had assumed that SNPS dated back a 100 years or so, I didn't consider the possibility of only being able to date as close as 1200 AD etc.
A7711 is just the "lead" SNP for the block. It's just the SNP that has been chosen as the name for the block but we don't really know if A7711 was the first SNP to occur in the block or the last. Only blocks are broken up by new testers do we find each SNPs were older.

Nqp15hhu
12-14-2020, 09:56 PM
My map changed (non: my snp is from County LíDerry, the American put Ireland down). Does this indicate a south eastern Scotland origin?

https://i.imgur.com/chxELIr.jpg

TigerMW
12-15-2020, 04:59 AM
My map changed (non: my snp is from County LíDerry, the American put Ireland down). Does this indicate a south eastern Scotland origin?

https://i.imgur.com/chxELIr.jpg

I don't think so. These SNP migration / tracker tools show you one thin line but they just aren't that precise. We will need a lot of ancient DNA to nail this down to a significant degree.
We can't even say for sure that L21 was born in the British Isles. The earliest probably L21 ancient DNA to-date was found in England but his teeth enamel indicate he was raised in an Alpine region.
L21 could be from Switzerland or possibly from England or possibly from France as the tracker shows.

L513 could be from England or Scotland, I think, or Belgium or Northern France. It's mostly speculation at this point.

Nqp15hhu
12-17-2020, 06:52 PM
I don't think so. These SNP migration / tracker tools show you one thin line but they just aren't that precise. We will need a lot of ancient DNA to nail this down to a significant degree.
We can't even say for sure that L21 was born in the British Isles. The earliest probably L21 ancient DNA to-date was found in England but his teeth enamel indicate he was raised in an Alpine region.
L21 could be from Switzerland or possibly from England or possibly from France as the tracker shows.

L513 could be from England or Scotland, I think, or Belgium or Northern France. It's mostly speculation at this point.

I think this map is based on the location of people's ancestors. So would this not be accurate?

TigerMW
12-18-2020, 01:59 AM
I think this map is based on the location of people's ancestors. So would this not be accurate?
These tools today are based on modern people’s reported ancestry, often only a couple of generations ago, and some times a matter of speculation. This is also biased by the geographic and socio-economic biases of consumer DNA testing. The tool builders may put their own twists (fudge factors) based on what they have read, just like you and me.
There is ancient DNA from scientific studies out there that helps us with our speculations (fudge factors) but there is not near enough of all the various timeframes to say we have clear and solid hypotheses among all of these different subclades.