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Brunetmj
02-28-2014, 12:06 AM
I belong to a small newly discovered subclade under L21. L21>DF13>FGC5496 In just a few weeks I have watched it branch twice. My question though is not about that specifically , it only led me to another line of thought. L21 has over 80+ subgroups with more on the horizon after the Big Y. Why questions is why? I do not see any of the other haplogroups with anywhere near this much branching. What does this significant amount of branching represent? It could just represent a large skew in the data base with the large number of Irish/Scot/English in the US. But still there are a large numbers of people from those populations that are not L21. The US also has other large populations generally not associated with L21? (i.e. German).
In short,Why is this?

Heber
02-28-2014, 12:34 AM
I belong to a small newly discovered subclade under L21. L21>DF13>FGC5496 In just a few weeks I have watched it branch twice. My question though is not about that specifically , it only led me to another line of thought. L21 has over 80+ subgroups with more on the horizon after the Big Y. Why questions is why? I do not see any of the other haplogroups with anywhere near this much branching. What does this significant amount of branching represent? It could just represent a large skew in the data base with the large number of Irish/Scot/English in the US. But still there are a large numbers of people from those populations that are not L21. The US also has other large populations generally not associated with L21? (i.e. German).
In short,Why is this?

Brunetmj,
Interesting question.
When CTS, Zhu and Wei first examined a Phylogenetic Tree produced by NGS, they observed the Expansion of R1b and M269. Later this was seen as L21 and in particular DF13 and M222, U152 and in particular L2 and an extreme expansion of DF27. This is not just observed in projects but also in published studies. Hopefully (in the coming weeks) we will see a new Phylogenetic Tree and can observe these expansions.

R.Rocca
02-28-2014, 12:51 AM
I belong to a small newly discovered subclade under L21. L21>DF13>FGC5496 In just a few weeks I have watched it branch twice. My question though is not about that specifically , it only led me to another line of thought. L21 has over 80+ subgroups with more on the horizon after the Big Y. Why questions is why? I do not see any of the other haplogroups with anywhere near this much branching. What does this significant amount of branching represent? It could just represent a large skew in the data base with the large number of Irish/Scot/English in the US. But still there are a large numbers of people from those populations that are not L21. The US also has other large populations generally not associated with L21? (i.e. German).
In short,Why is this?

Pretty simple explanation...there are a lot more people that are L21 that are getting FG testing and even PGP and UK10K is heavily L21. The more samples you have to compare, the likelier you are to find matching SNPs.

Brunetmj
02-28-2014, 02:01 AM
Pretty simple explanation...there are a lot more people that are L21 that are getting FG testing and even PGP and UK10K is heavily L21.

So if an equal number of people , of say U152 , tested , we would see an equal amount of sub branching?

MJost
02-28-2014, 03:35 AM
Mark,

Check out this paper as to why a significant amount of branching probably occurred:

Agriculture driving male expansion in Neolithic Time
C. Wang etal Nov 27, 2013

http://arxiv.org/abs/1311.6857

Look at Fig 1 to see R1a's and R1b's more recent expansion width due to the suggested agriculture link.

http://arxiv.org/ftp/arxiv/papers/1311/1311.6857.pdf

MJost

Mikewww
02-28-2014, 02:27 PM
My question though is not about that specifically , it only led me to another line of thought. L21 has over 80+ subgroups with more on the horizon after the Big Y. Why questions is why?

Pretty simple explanation...there are a lot more people that are L21 that are getting FG testing and even PGP and UK10K is heavily L21. The more samples you have to compare, the likelier you are to find matching SNPs.

Richard is correct but I think there is an additional factor that Mark J alluded to.

First, as Richard indicated, there is heavy and deep testing penetration of the L21 population, relative to other populations. I say this lovingly as "I is one" but I think we are a bit crazy. This gives me the opportunity to present on my favorites.
“The great Gaels of Ireland are the men that God made mad,
For all their wars are merry, and all their songs are sad. (http://www.goodreads.com/quotes/139451-the-great-gaels-of-ireland-are-the-men-that-god)” Before we carried away, we are all mixed and L21 is quite varied beyond people that were Medieval Age Gaels... Brits for instance, but I was at an Irish Pub yesterday and we seem a bit crazy. :) Seriously, it can be as simple as a lot of American immigrants apparently were L21 people and today a lot of Americans are interested in genetic genealogy - relative to the rest of the world.

The other factor I was alluding to relates to a persistent and fairly late (starting Bronze Age or so) population growth and lineage survival rate. This probably applies to several of the large haplogroups in R1b and to a few others as well, and that is just a Euro-centric view.

Andrew Lancaster
02-28-2014, 03:51 PM
So if an equal number of people , of say U152 , tested , we would see an equal amount of sub branching?

Maybe, but the effect could be more complex. One thing is that there are more R-L21 people in TOTAL than R-U152. Another thing is that the % of the R-L21 population doing this type of testing is also particularly high (because they have a lot to gain by testing - they know they'll will have a lot of people to compare to).

If you actually got to a point where you had knowledge of all the branching of a similarly percent of BOTH these populations, then you would expect R-L21 to still show more branching simply because it is a bigger tree, with more branches (people) in it.

JRW
03-01-2014, 03:50 PM
I agree with the earlier postings regarding the L21 population size in general and the number of L21 who take DNA tests account for the large number of branches in the L21 tree. And, I don't think that the L21 mutation on the Y chromosome changes the probability of a future Y chromosome SNP mutation relative to other haplogroups.

However, I have always been somewhat puzzled by how many SNP mutations apparently took place in a relatively short period of time in what had to be a small population. The mutations of L11 to P312/U106 to L21/U152 to DF13 took place over a short period of time, particularly when one considers the effects of genetic drift -- meaning that many lines (having other mutations) descending from that period died-out. The rate of mutation just appears to be high. So, I have to wonder (pure speculation on my part) if there was an environmental or cultural factor as well. Specifically, the process of smelting metals releases mutagenic compounds -- from the ores themselves to the coal used to fire the smelters. Impurities such as cadmium are well-recognized mutagens released into the air during the smelting process. Given that the Bell Beakers and Bronze Age populations were metal workers, it's conceivable that environmental/cultural factors had a role in the "bushiness" of the early tree.