Major drop in mtDNA, specifically T1a1

[mabrams]

What happened to the number of mtDNA testers?

In November, 2020 the public FTDNA mtDNA haplotree reported 2930 T1a1.

Today, there are 2262 T1a1. About 700 less

I can provide screenshots.

On July 1, I noticed a slight decrease in my Y matches. But the T1a1 drop is major.

Is this decrease across the entire mtDNA stats or just T1a1?

[KATM]

Hmm, I'm not sure. . . my first thought was that it might be due to some who were formerly assigned T1a1 being reassigned to a subclade, such as T1a1a1, T1a1b, etc. That would change the total for T1a1, but since the mtDNA Haplotree is based on Full Sequence results (which don't change haplogroup assignments, as Y-DNA results might change due to new SNPs being discovered), I really don't think that's the cause. You are right, a difference of almost 700 less seems far too much for an updated subclade count (even if reassigning could be the answer).

This looks like a case where a request to Customer Support would be best, unless someone else pipes in here with an answer.

As far as the entire mtDNA stats, I noticed that on the mtDNA Haplotree page, the statement at the top shows "the world’s largest mtDNA database containing 170,000 mtFull Sequences from over 180 different countries." This statement is the same as shown as the current page for the Public mtDNA Haplotree in the FTDNA Learning Center.

But, following the "Help" link at the top right of the mtDNA Haplotree page, it goes to a link for a page Public mtDNA Haplotree Overview, which says "the world’s largest mtDNA database containing over 5,000 branches and 200,000 mtFull Sequences from nearly 200 different countries." So, it appears that there has been an increase in overall mtDNA Full Sequence testing. Otherwise, the information on the latter page seems to be the same as the former, and neither mentions anything about why a total count for a branch might decrease.

This page in the FTDNA Learning Center has a section for "About The FamilyTreeDNA Database" at the bottom, which shows FTDNA has "211,854
mtFull Sequence records."

[mabrams]

KATM, Thank you for quick response.....

If I looked at RSRS, Country Report, I see 165,554. I think this is an accurate total for the entire Public Tree, but not sure.

btw, if people are reassigned to a subclade, I dont think that affects the current total for T1a1 etc, since they are still considered T1a1 in a technical sense

[randalgibbs]

There's currently 165,568 kits on the mtDNA tree. (Country report on RSRS).
On July 1st it was 208,428, on August 1st it was 164,834. Something happened sometime in July.