Question about haplogroup matching

Question

My maternal uncle took a y-DNA test.  It placed him in a haplogroup that 23andme referred to as extremely rare as only 1 in 250,000 customers match.

Where my question leads is this:

We had originally thought that my maternal grandfather’s paternal Lowe line descended from the Gunpowder Road Lowe’s of Maryland.  I have found a Lowe DNA project on Familytree dna.  Checking the results, the Gunpowder Road Lowe ancestors show I-M253.  My uncle’s dna tested I-Z74.  

I realize both of these belong to the I1, if I am not mistaken.  So, am I following the wrong line? Should I redirect my research? For further reference, no one on the family tree dna Lowe DNA project tested at I-Z74.  I guess I am at a loss.  I don’t know a lot about Haplogroups and how everything should match up.  If anyone can help me at all, I would be forever grateful.

I also noticed my uncle’s y dna test does not match any of the Lowe men who have tested on WikiTree.

Thank you for anyone who could help.

Answer 1

I-M253 is another name for I1 - they are the exact same haplogroup.  I-Z74 is much further down because your test provided more SNPs (or the SNPs of the other test takers were inferred from STR results): M253 > DF29 > CTS6364 > L22 > CTS6868 > Z74 

So based on that your uncle still matches up to the provided test results.

Comments

Thank you very much for clearing that up.  So far he hasn’t had a y DNA match to any other Lowe males.  I have only found 3 other matches to the I-Z74.  Those were a McNeal, a McNeill, and a Currie (of which 2 of the 3 were from Scotland).  So it has been an adventure.  This is all so mind boggling to me.  Thank you for helping.

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The FTDNA surname projects use both STRs and SNPs if available. If the other member's STRs show no match to your uncle's STRs then he's descended from a separate family line. The STRs should be the primary method to match an individual to a family line within a genealogical time frame. Then, if the STRs match, then the haplogroup (SNPs) may be used to rule out or verify that the STR match is not due to chance from "convergence".

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Thank you so much for helping clear up my confusion.  You did a great job of explaining it all to me so that a simpleton like myself could understand.  I really appreciate your assistance.

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No problem at all!