Click here to download our 2019-09-28 draft tree for I-L233
This update shows two new branches below I-Y4252, they are named I-BY82831 and I-BY117344. Each of these branches contains one German-ancestry man and one English-ancestry man.
At the moment I-Y4252 contains 22 immediate descendant branches. 14 branches are named, and 8 branches are unnamed because they contain only a single Big Y sample. The Big Y-700 test hasn't revealed any new SNPs immediately below I-Y4252 that could resolve these 22 branches into fewer haplogroups immediately below I-Y4252.
I-Y4252 had its initial expansion approximately 1800 years ago according to YFull's current calculation (previously the MRCA age was slightly older). If this expansion occurred in continental Europe and some branches later arrived in Great Britain, we would expect to see more branches in continental Europe and fewer branches in Britain. But currently we see the opposite: there are many branches that have been found only in Britain/Ireland.
I think this is probably because British and Irish-ancestry men are highly over represented in the Big Y customer database, even compared to countries like the Netherlands, Germany and Denmark. As more men do tests, I think we will see that most of the branches that are currently British-only will contain some continental European men, and that's exactly what we are seeing with I-BY82831 and I-BY117344 and with earlier discoveries like I-BY65456.
Click here to find our previous tree for I-L233
Click here for a brief description of the I-L233 haplogroup