Here's Kitty Cooper's blog post about it
Notes from the official announcement from FamilyTreeDNA to their volunteer group administrators (such as myself) are below.
This should be of particular interest to those who have only tested at Ancestry.com as they simply do NOT provide you with sufficient information to check which ancestor was responsible for your dna match.
A tree match is just a simple pointer on where to do the traditional research to show the linkage indicated. It is not necessarily where your dna match is.
To find who passed on a particular segment of dna to you and your match(es), you need to find which spot on which chromosome you share with others and work together to then determine if it is a triangulated match, ie person A matches both person B and person C on chromosome n from point x to point y AND person B matches person C at the same spot.
Until you have checked that person B also matches person C, you don't yet know if your matches are from the opposite sides of your pair of chromosome n, or the same side, which can still be from either of your paternal or maternal ancestry until you have more clues.
Once you have checked however, you do now know that a common ancestor between you all is responsible for passing that particular bit of dna that has survived down the generations to you. You may be pleasantly surprised to find completely different tree linkages!
Ancestry does not provide the tools necessary to do this.
FamilyTreeDNA does, as do 23andme, and of course, GEDMatch.com who accept raw data files from all three companies for comparisons.
So, if you are interested in maximising your investment in your dna test with Ancestry in particular, do consider this transfer.
Club together to get the referrals working for you.
If you have a surname from any of the DNA projects listed on the top rhs of this blog do consider joining your appropriate project after you have transferred your data. They aren't just for Y-dna, we accept all clues for the ancestry of the surname and their connections, which autosomal dna certainly provides, albeit less directly than y- or mt-DNA.
If you are one of my relations, or already know you are a dna match to myself or one of my close relations, please also consider joining my autosomal dna project FFLornaHen so that we can work together to explore our genetic heritage and break down some of those brick walls.
From the FamilyTree DNA announcement to Group Administrators:
.. for the first time ever, people that have taken an AncestryDNA™ or 23andMe© (V3) test can transfer into the FTDNA databases for free by visiting https://www.familytreedna.com/AutosomalTransfer? and following the instructions to upload their raw data file.
Within an hour or two, we provide a preview of what’s waiting if they transfer by showing the top 20 matches along with an estimate of the total number of matches in the FTDNA database.
Full functionality can be unlocked by either paying $39 or recruiting four other people to upload, thus unlocking the rest of the matches.
Here are some important points to know:
As of Friday afternoon, Ancestry was experiencing difficulty with file downloads. ... If you (or your group members) have previously uploaded files to GEDmatch, there’s a fair chance the download will still be on your computer. Look for a filename like dna-data-yyyy-mm-dd.zip.
We only accept the 23andMe V3 chip that was used on tests sold between November 2010 and approximately November 2013. There are a couple of ways to find out what chip was used for your test other than simply the timeframe. One is size; v3 chip files are about 7.83 MB where V2 and V4 chips are smaller. If you’re tech savvy, you can unzip the file and check chromosomes: Chromosome 1 for v3 starts at 82154 (rs4477212) where v4 starts at 734462 (rs12564807)and v2 starts with position 742429 (rs3094315).
We do not have any plans to accept V2 or V4 chips. if you try to upload the wrong chip version, the system will tell you that the file doesn’t have sufficient data. Since neither chip contains enough of the SNPs included in Family Finder, we would have to impute too much data. Basically we’d have to make assumptions about the missing SNPs that we’re just not willing to make at this point.