AncestryDNA hands over your raw data as one text file with five columns and several hundred thousand lines. This guide takes a real file apart, line by line, and sets it beside a 23andMe file.
Written by Martin Pechhacker, Vienna Last checked 19 September 2026 14 min read
The download is a zip archive whose name starts with dna-data-. Inside it is one plain text file, AncestryDNA.txt, whose columns are separated by tabs.
Each line holds five fields: rsid, chromosome, position on build 37 (GRCh37), allele1 and allele2.
The sex chromosomes and the mitochondrial DNA are numbered: 23 is X, 24 is Y, 25 is the stretches X and Y share, 26 is the mitochondrial DNA. A 0 in both allele columns means the chip could not read that position.
The third line of the header names the chip, array version V1.0 or V2.0. The two share about two thirds of their positions, and what can be read from the file differs sharply between them. Samples processed since autumn 2025 give a third, smaller file.
The excerpt shows how every AncestryDNA file opens: Ancestry's comment lines, the line that names the columns, then the data. The comments are quoted from a file generated in November 2025, which a Personal Genome Project participant made public under open consent. The three data rows belong to the genome behind the demo, set in Ancestry's layout. Sources 1 7
#AncestryDNA raw data download
#This file was generated by AncestryDNA at: 11/17/2025 17:02:17 UTC
#Data was collected using AncestryDNA array version: V2.0
#Data is formatted using AncestryDNA converter version: V1.0
#Genetic data is provided below as five TAB delimited columns. Each line
#corresponds to a SNP. Column one provides the SNP identifier (rsID where
#possible). Columns two and three contain the chromosome and basepair position
#of the SNP using human reference build 37.1 coordinates. Columns four and five
#contain the two alleles observed at this SNP (genotype). The genotype is reported
#on the forward (+) strand with respect to the human reference.
rsid chromosome position allele1 allele2
rs4988235 2 136608646 A A
rs713598 7 141673345 C C
rs1815739 11 66328095 C C
How an AncestryDNA file opens. One run of comment lines is left out, marked [...]: a notice in capital letters that the data is for personal and genealogical use, and that keeping the downloaded copy safe is up to you. The three rows are the demo genome's own calls. Sources 1 7
From there the file runs on unchanged for several hundred thousand lines, sorted by chromosome: 1 to 22 first, then 23, 24, 25 and 26. Tabs separate the five fields. Every line ends in the Windows line ending, which matters only to software: a script that splits on the line feed alone finds an invisible extra character after the last column.
One line of an AncestryDNA file and its five fields.
rsid
The name the position carries in dbSNP, the public catalog of known variants. The header promises an rsID "where possible", and nearly every line has one: in a file from the earlier chip, twelve lines carry an internal identifier starting with VGXS instead.
chromosome
1 to 22, then numbers where other companies use letters: 23 is the X chromosome, 24 the Y chromosome, 25 the short stretches at the ends of X and Y that the two share, and 26 the mitochondrial DNA. Ancestry's help page mentions 23 and 24; the full set is the numbering of PLINK, a standard research tool. The Y lines are present in every file; in a file from a woman nearly all of them read 0. Files from the earlier chip have no 26 lines.
position
Where the position sits on its chromosome, as a base count. The header calls the build "37.1" and Ancestry's help page names it GRCh37, which is also what a 23andMe file uses. Build 38 counts the same places differently, so a tool has to know the build before it matches anything.
allele1, allele2
The two letters read at this position, one for each copy of the chromosome, split over two columns. A and A is what a 23andMe file writes as AA; A and G is its AG. Which letter lands in which column means nothing. Ancestry reports them on the forward (plus) strand, the orientation public databases use.
Nothing else is in the file. What a line means comes from outside it: the rsid is looked up in published research, and the two letters are read against what the studies found. The three example rows have public pages of their own: rs4988235, a position near the lactase gene that goes with digesting milk sugar as an adult; rs713598 in TAS2R38, which shapes how bitter some foods taste; and rs1815739 in ACTN3, a muscle-fiber gene.
SIDE BY SIDE
ANCESTRYDNA
23ANDME
Columns
Five: rsid, chromosome, position, allele1, allele2
Four: rsid, chromosome, position, genotype
Genotype
Two columns with one letter each: A and G
One column with two letters: AG
Sex chromosomes, mitochondrial DNA
23, 24 and 26
X, Y and MT
The stretches X and Y share
Listed as 25
Listed under X
No call
0 in both allele columns
--
X and Y in a man's file
The same letter twice: C and C
A single letter: C
Insertions and deletions
I and D in the allele columns (newer chip only)
II, DI or DD in the genotype column
What the header names
The array version (V1.0 or V2.0) and build 37.1
Build 37, but not the chip
Build and strand
GRCh37, plus strand
Compared in public files from both companies. Sources 1 2 3 8
Both files hold the same kind of data. A position that both chips read carries the same rsid, the same position number and the same letters in both files. The differences are in the packaging, and they are why a tool written for one layout misreads the other: it looks for a fourth column holding two letters, or for a chromosome called X. ReadYourDNA reads both layouts as they are, so nothing needs converting before an upload. The 23andMe layout is covered line by line in What is inside a 23andMe raw data file. Source 8
Ancestry delivers the raw data as a zip archive named dna-data- followed by the date. Inside is one text file, AncestryDNA.txt, about 18 MB; the zip itself is about 6 MB. ReadYourDNA takes the zip as delivered. Sources 4 9
Sign in to Ancestry and open your DNA settings: in the "DNA" menu, open your results summary and press "Settings". If you manage more than one test, pick the one to download.
Scroll down to the section "Download or Delete" and choose "Download DNA data".
Tick the box to confirm that you understand and press "Continue".
Verify your account in one of two ways: enter your password, or have a code sent to your email address and enter that.
Wait for the email from Ancestry and choose "Download DNA Data" in it. The file is not attached to the email: the button opens a page where "Download DNA Data" starts the download.
The wait
Ancestry says the email can take up to 24 hours to arrive. The link in it works once and expires after a week, and after several requests only the newest email holds a valid link. "Download or Delete" are two separate choices: what you download is a copy, and your results and matches stay at Ancestry as they are.
READING THE ALLELE COLUMNS
Most lines carry two of the letters A, C, G and T. Four other patterns occur, and each has exactly one meaning.
WHAT YOU SEE
WHAT IT MEANS
A G, C T and so on
The usual line: one letter per copy of the chromosome, in no particular order.
0 0
Ancestry's way of writing a no-call, a position the chip could not read in your sample. The public files behind this guide have between about 300 and 4,500, well under one percent of the lines, and they fall on different positions in every sample.
The same letter twice on 23 and 24
A man has one X and one Y chromosome, so there is only one allele to read. An AncestryDNA file still fills both columns and writes that allele twice, where a 23andMe file writes a single letter. The 26 lines, the mitochondrial DNA, are written the same way in every file.
0 0 on the 24 lines
A file from a woman. The Y positions are listed in every file, and without a Y chromosome nearly all of them come back unread.
I and D
A short stretch of DNA that is added or missing, where other lines have a letter. Ancestry's help page calls I "extra DNA" and D "missing DNA". Most files from the newer chip carry about 8,000 such lines; files from the earlier chip carry none.
Counted in public AncestryDNA files from both chips, generated between 2013 and November 2025. Sources 1 2 3
A chip can misread
Every line is the reading of one probe, and probes are not perfect: genotype the same person twice and a few letters come out different. Whatever is built on the file carries that along, so a good report says how reliably each position is usually read. The 23andMe guide quotes what 23andMe's own header says about it.
Ancestry has used two genotyping chips, and the file says which one read your sample. The third line of the header reads "Data was collected using AncestryDNA array version: V1.0" or "V2.0". Ancestry moved to the second chip in the middle of May 2016, so the version follows the day your sample was processed, not the day you download: a sample from 2014 downloaded today still gives a V1.0 file. Sources 1 3 6
ARRAY VERSION
SAMPLES PROCESSED
LINES IN THE FILE
CHROMOSOME CODES
V1.0
Until mid-May 2016
701,478
1 to 25
V2.0
Mid-May 2016 to autumn 2025
About 650,000 to 678,000
1 to 26
The newer file
Since autumn 2025, as FamilyTreeDNA describes it
About 430,000
No Y-chromosome or mitochondrial lines
The first two rows: line counts and codes from the public AncestryDNA files ReadYourDNA has read, generated between 2013 and November 2025, and the date of the change as the genetic-genealogy writer Roberta Estes reported it from Ancestry in May 2016. The third row is from FamilyTreeDNA. Sources 1 2 3 6 13
The change was a large one. The two chips share about two thirds of their positions; much of the rest of the earlier chip was replaced, by the reporting of the time, with positions of medical interest. The newer chip has been revised since as well: about four fifths of the lines of a V2.0 file from 2018 are still there in one from 2025, and the line count has moved in steps between about 650,000 and 678,000. The header has said V2.0 throughout: a file downloaded in November 2025, from a sample read years earlier, still does. Source 6
A third kind of file since autumn 2025
Two services that read these files report a change. FamilyTreeDNA's help page, updated on 9 September 2026, accepts AncestryDNA files from samples processed until September 2025 and says of the newer ones: "If the file has ~430,000 rows, it's the new, unaccepted version. These files will not have mtDNA and/or Y-DNA SNPs at the bottom". It adds that the header of such a file may name NGS, or may still say Array Version 2. Genetic Lifehacks dates it differently: "Ancestry changed its data files in March 2026 and now covers fewer variants." Unlike FamilyTreeDNA, it says: "Those files still work".
The date in the header is the day of the download, so the line count is the surer sign. Every public file behind this guide comes from a sample read before that change; the figures above describe the two older kinds.
Sources 13 14
WHAT ANCESTRY SHOWS
Ancestry uses these genotypes for your ancestral regions (the results it used to call the ethnicity estimate), for your DNA matches and for its traits feature. For a little over a year it also sold a health product, AncestryHealth. On 14 January 2021 Ancestry announced that AncestryHealth would not be sold after 15 January 2021, with customer support continuing through mid-2021. It has offered no health reports since, so the raw data file is the way from an AncestryDNA sample to anything beyond family history. Source 10
WHAT A READER CAN DO WITH IT
An AncestryDNA file from either chip carries everything the four ReadYourDNA reports need, so each of them can be built from it. The chip decides how full each report gets, because a report can only cover positions that are in the file. The gap between the two Ancestry chips is wider than between any two 23andMe chips, which is why the third line of the header matters so much. The newer, smaller file reads fewer positions than either; how far it fills each report shows after the upload, because every report states the figure for your own file. Source 11
REPORT
EARLIER CHIP (V1.0)
NEWER CHIP (V2.0)
Variant explorer
About a third of the variant cards
About three quarters, as with a file from the current 23andMe chip
Polygenic trait scores
Every trait is scored; each trait page states how many of its positions the file covered
Every trait is scored
Medication response
14 or 15 of the 23 pharmacogenes have positions in the file; the others are reported as not called rather than guessed
16 to 19 of the 23, in line with a 23andMe file
Carrier annotation
About 1 percent: positions for 35 to 42 of the 3,321 conditions in the catalog
57 to 68 percent of the 3,321 conditions, more than any 23andMe chip
Measured on AncestryDNA files from both chips. After an upload, each report shows the figure for your own file. Sources 11 12
A V1.0 file and the carrier report
Carrier annotation looks for specific rare positions that a chip either includes or does not, and the earlier chip includes very few of them. With a V1.0 file the carrier report stays nearly empty, and an empty line there says nothing about whether you carry a variant: the position was never read. The other three reports work on both chips.
ReadYourDNA reads a raw DNA file you already have and returns polygenic trait scores, medication-response annotation, carrier annotation and an annotated variant explorer, with the study behind every number. One payment, no subscription, and you can delete the file at any time.
Educational, not medical advice.
Most of your genome. Ancestry's chip reads 650,000 to 700,000 places, in the newest files about 430,000, out of roughly 3 billion. A variant the chip does not carry never appears in the file, and a missing line is no sign that you lack the variant.
Anything bigger than a few letters. Long deletions, doubled stretches, repeats and rearranged pieces of a chromosome do not show up in a chip file. The newer chip's I and D lines cover short insertions and deletions only.
What your genes are doing. Gene activity and methylation shift over a lifetime, and a genotyping chip reads neither.
Your Ancestry results. Your ancestral regions, your DNA matches and your family tree are computed from the file or kept beside it, and none of them is in it. What Ancestry shows you is worked out from these lines; the lines are all you download.
Your name and details. The header carries the date, the array version and the notice, and nothing about you: no name, no account and no sample number. The letters still point to one person, which is why the left-out notice in the header puts the safekeeping of the copy in your hands.
Yes. The download is in your DNA settings, in the section "Download or Delete", and the steps are further up this page. Ancestry gives it to the owner of a test and to anyone the owner has made a manager, and it confirms the request by email first, so allow up to a day for the file.
Download the zip as described above and upload it as it is. ReadYourDNA recognizes the AncestryDNA layout by its five columns, reads the numbered chromosomes, and names the chip it found in the carrier status report. There is nothing to unzip, rename or convert.
Open the file and read the third line: "Data was collected using AncestryDNA array version: V1.0" or "V2.0". If the header is gone, the line count settles it: 701,478 lines of data mean V1.0, anything between about 650,000 and 678,000 means V2.0, and about 430,000 lines without Y-chromosome or mitochondrial lines is the newer file that FamilyTreeDNA describes.
GRCh37. The header says "human reference build 37.1", Ancestry's help page says GRCh37, and every public file we have read agrees, from 2013 to November 2025. Nothing has to be converted before an upload: ReadYourDNA takes the build from the header and does any conversion itself.
Two zeros are Ancestry's no-call: the chip got no clear reading there. Every file has some, from a few hundred to a few thousand, and they say nothing bad about your sample. A woman's file adds the 24 lines to them, because those are Y chromosome positions and she has no Y to read.
Yes, as a tab-separated text file; any spreadsheet program imports it. Expect a slow start with more than 650,000 rows, and work on a copy, because a spreadsheet can alter cells when it saves and an upload needs the file the way Ancestry wrote it. For a quick look, a plain text editor is faster.
No. Ancestry stopped selling AncestryHealth on 15 January 2021 and has not offered health reports since. Its DNA product covers ancestral regions, DNA matches and traits.
Every figure on this page was read from the page named, on the date named. ReadYourDNA publishes this page. If something here is out of date, write to support@readyourdna.com.
Personal Genome Project participant hu25E03E, public AncestryDNA data file (generated 17 November 2025, array V2.0)
my.pgp-hms.org/profile/hu25E03E
The header lines quoted in the example, the five-column layout, the line count (677,436), the numbered chromosomes, and the counts of no-calls and of insertion and deletion codes.
Data was collected using AncestryDNA array version: V2.0
Genetic data is provided below as five TAB delimited columns.
using human reference build 37.1 coordinates
The genotype is reported on the forward (+) strand with respect to the human reference.
Read on 19 September 2026
Personal Genome Project participant hu416394, public AncestryDNA data file (generated 22 April 2018, array V2.0)
my.pgp-hms.org/profile/hu416394
An earlier V2.0 file from a man: 650,410 lines, no insertion or deletion codes, the same letter twice on the X and Y lines.
Personal Genome Project participant hu0488C7, public AncestryDNA data file (generated 17 December 2013, array V1.0)
my.pgp-hms.org/profile/hu0488C7
A V1.0 file from a woman: 701,478 lines, chromosome codes 1 to 25, twelve internal identifiers, every Y line a no-call.
Data was collected using AncestryDNA array version: V1.0
Ancestry Support, "Downloading DNA Data"
The download steps, the two ways to verify, the wait for the email, the rules for the link, the name of the zip file, who may download, and Ancestry's own description of the columns.
Verify your account by choosing 1 of 2 methods
The email can take up to 24 hours to arrive.
A download link can only be used once. It will expire after a week.
The file name will be dna-data-(date).zip.
In some cases, the X and Y chromosomes are referred to as 23 and 24.
AncestryDNA reports data for the SNPs on the forward strand with respect to the human reference genome (GRCh37).
Only the owner of a test and anyone made a manager by the owner has access to a test's DNA Data.
PLINK 1.9 documentation, the section on chromosome codes
The numeric chromosome codes: X is 23, Y is 24, the pseudo-autosomal region of X is 25, the mitochondrial DNA is 26.
Roberta Estes, DNAeXplained, "Ancestry Modifies Their Autosomal DNA Chip" (15 May 2016) and "Ancestry V1 vs V2 Test Comparison" (5 October 2016)
The change of chip in the middle of May 2016, the replaced positions, and the header line that names the version.
Ancestry, "Ancestry deepens focus on Family History; will discontinue AncestryHealth" (14 January 2021)
The end of AncestryHealth sales and of its customer support.
AncestryHealth will not be sold after January 15, but customer support continues through mid-2021.
Read on 18 September 2026
FamilyTreeDNA Help Center, "Autosomal DNA Transfers" (updated 9 September 2026)
A description of the AncestryDNA file produced for samples processed since autumn 2025, from a service that reads these files.
AncestryDNA® array V2 (May 2016 - September 2025)
If the file has ~430,000 rows, it's the new, unaccepted version. These files will not have mtDNA and/or Y-DNA SNPs at the bottom
Genetic Lifehacks, "Membership"
www.geneticlifehacks.com/membership
A second report of the changed AncestryDNA file, with a different date, and that it still reads the newer files.
A note on AncestryDNA: Ancestry changed its data files in March 2026 and now covers fewer variants. Those files still work
Read on 19 October 2026
ReadYourDNA demo
The three example rows, on the sample genome.
What is inside a 23andMe raw data file
readyourdna.com/guides/23andme-raw-data-file-format
The 23andMe side of the comparison, from two public 23andMe files.
ReadYourDNA FAQ
Which files are accepted, and that the zip can be uploaded as it is.
ReadYourDNA methodology
How array files are read, and what each report needs.
ReadYourDNA carrier status
The catalog size and the per-file coverage line.
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