Intermediate DNA for Genealogists – HANDOUT
1. Brief Overview I
If two people have matching DNA, they have a common ancestor!
If two people don’t have matching DNA , they don’t have a common ancestor!
2. DNA is passed from parents to children
Y-DNA is only passed from fathers to sons
mt-DNA is only passed from a mother to her children
at-DNA is passed from both parents to a child
[each child gets a different mix of DNA from their parent]
3. Overview of uses for types of DNA
Y-DNA: Use to Trace the all-male line = SURNAME Project (easier to research)
mt-DNA: Use to Trace an all-female line = DIY project (different surname = difficult research)
at-DNA: Use to Search for all ancestors; by males or females; share/compare with matches
4. DNA Terminology
Haplotype: your specific Y or mt-DNA result (your combination of numbers)
Haplogroup: the main branches of the Tree of mankind
Similar haplotypes are under a haplogroup
From all-male or all-female lines
Each of your different ancestors may well be from different haplogroups
Chromosome (Chr) – Your DNA is made up of 46 chromosomes, plus mtDNA
Autosomal Chr: Chr 01 to 22. You get one full set from each parent (total=44)
Each parent mixes (recombination) their two Chr01s into one Chr01 for the child
Each parent provides one Chr01-22 to child, so child gets full set of 44 Chr from both parents
So each child has roughly ¼ of his/her DNA from each grandparent
Sex Chr: If Dad provides a Y, it’s a boy; if an X, it’s a girl; Mom provides an X (total=2)
Y-Chromosome (father to son) is the smallest Chr (very small part of your DNA)
Mitochondrial (mtDNA) is not a Chr; very small (~16,500 places) compared to any Chr
SNP (pronounded “snip”) – a place/site on the DNA that often has a different value
Some DNA tests look at these sites for the change; if so, you have that SNP
atDNA tests (Family Finder) look at over 700,000 such sites
5. Y-DNA Concepts
Matches – when your Haplotype is the same of close to another
Close: 11/12; 23/25; 33/37; 60/67; 102/111
Mutation = change; usually one number of a haplotype differs by +/- 1
Where in your ancestry does a mutation occur?
Out of a Y-25 test, a single mutation is expected every 7 generations – ON AVERAGE
Always between a father and son (father has one value, son has another)
After a mutation, all succeeding descendants carry it
Random location (not at generation 7); 9G to 8G-grandfather OR grandfather to father
A change of one makes no difference – it’s still a match
However, a mutation can be used to track a branch line, or link two branches
How many markers to test? – I recommend Y-37; other recommend the max you can afford
Y-12 is too few (many apparent matches are not); Y-25 has worked well for BARTLETT Project
Y-67 and Y-111 usually don’t offer any additional genealogy info
You can always upgrade if needed
NB: More markers results in fewer matches, not more (don’t upgrade for more matches)
106739097 9/1/2012 [P a g e | 1]
6. mtDNA Concepts
Matches – usually exact or one difference
Look at FTDNA page for matches (let them do the comparisons)
Use www.mitosearch.org to list you mtDNA results, and find more matches
Finding an unknown maiden surname of an Ancestor – it’s hard work!
Trace an all-female line of descent to a living son or daughter of all-female line
Get an mtDNA test; Repeat for a different all-female line – to be sure
Contact the matches – look for their line to intersect the place/time of your ancestress
Investigate family links – their line and your line
If no success, then create one – mtDNA test descendants of neighbors, friends, witnesses, etc.
7. atDNA - 3 major vendors:
FamilyTreeDNA – Family Finder DNA test - $289
- Best DNA company for genealogists
- Names and emails of Matches – most are genealogists, or want to be
- Some Matches list surnames and/or Ancestries
- Downloads: names & emails, etc.; segment info; raw data
23&me – Relative Finder listing - $299
- Largest database, but many don’t do genealogy
- Names hidden, until they accept your invitation
- Test includes medical info; so be careful, talk with your Dr. before you test
- Downloads: Some names (no emails), etc.; segment info; raw data
AncestryDNA – by Ancestry.com - $99 during Beta period
- Unknown database, being built by Beta testers
- Most matches have linked, robust Trees at Ancestry
- Good ancestry matching tools; good genealogy research tools
- Downloads: none (no names, no emails, no segment data, no raw data)
All three have some ethnicity calculations
8. atDNA Terms
Segment – a chunk of DNA that you and your match share
- Very probably the segment came from a Common Ancestor
centiMorgan (cM) – the unit of measure of segment length
- All matches have at least one segment of 7cM length
- Smaller segments may match, but not be from Common Ancestor
SNP - >700,000 sites tested, where known variations occur
- Each matching segment usually includes 700 or more SNPs
9. How to use atDNA
Phase I – Get Ready (1-2 months)
- Develop a robust Ancestral Tree
- for atDNA matching, throw in the kitchen sink
Include Alternates, good guesses, hints, Ancestry.com, etc, etc.
- your match wants one Common Ancestor from your Tree
- your match will scan your info looking for familiar surnames
- make a GEDcom for uploading elsewhere (WorldConnect, GEDmatch)
- make an alpha surname list from your Tree
- add Patriarch info to surname list to highlight your line
- Develop a standard email/message (make it easy for them to find Common Ancestor)
- include your name and email
- include links to your Tree: WorldConnect, Ancestry, etc.
106739097 9/1/2012 [P a g e | 2]
- request your match’s Tree
- short description of your whole ancestry in general
- optional: add your Patriarch list – so it’s handy for them
- be upbeat, look forward to identifying the Common Ancestor
Phase II – Communicate (1-2 years; then new matches, monthly)
- Communicate with every match
- send your standard email/message to ALL matches
- one to each match (personalize, if you want) OR send one email to all (bcc their emails)
- read/study/respond to all replies
- be persistent; follow up with new info or questions
Tip: I keep a Word document with sentences/paragraphs I use over & over: just copy/paste
Tip: download a spreadsheet of matches – track most recent send/receive emails/messages
Tip:
- Share info
- look at every Tree you can; also study place/time matches
- research your match’s Tree, if you see something promising
- Determine Common Ancestors
- Usually the husband/wife of your and match’s ancestors
- Often, with Colonial ancestors, there are more than one Common Ancestors
- Carefully document your matches’ ancestral line
Phase II – Cousins
Will a Cousin Match with atDNA?
- Close relatives will always match:
- Parents, Aunts/Uncles, 1st Cousins, 2nd Cousins
- 3rd Cousins match 9/10 times; 4th Cousins 5/10 times
- So a specific 3rd Cousin, or greater, may not match
- BUT, you have many more 3rd Cousins than 2nd; 6th than 5th
- SO, you will get “Distant” cousin matches (but, it’s random)
Will there be matching cousins for all my ancestors?
- Yes, for all of your nearer ancestors – probably all 64 4G-grpar
- Depends on three things:
- Did atDNA survive from a distant ancestor to you?
- Have cousins from each distant ancestor done atDNA test?
(some immigrant ancestor families still in the Old Country)
- Do you have all your ancestors documented?
(segments from undocumented ancestors can’t be linked)
Phase II – Adoptions
Finding ancestry of Adoptees, etc.
- Close Matches – Look for 1st, 2nd, 3rd cousin matches
- Get their Ancestry Tree
- A 2nd cousin has 8 Great-grandparents, one is yours!
-Track descendants of matches’ ancestors to your origin
- Triangulate
- Find two, or more, matches on overlapping segments
- Ask them if they match each other
- If so, help them find their Common Ancestor = yours!
- Find more matches
- Upload raw data to www.GEDmatch.com ; compare all
106739097 9/1/2012 [P a g e | 3]
- Patterns: SURNAMEs; place/time matches to your origin
- Study your matches’ Trees for recurring SURNAMEs
Tip: virtually all matches are your kin; study their Trees; be positive
Phase III - Mapping
- Download a spreadsheet
- at FTDNA – 5 at a time from Chromosome Browser
- at 23&me – from Ancestry Finder (Ancestry Labs TAB)
- includes names, Chr#, Start, Stop, cM, etc
- Sort on Chr# and Start to get a map of your genome
- from first segement on Chr 01 to last one on Chr 22
- Add columns to suit your interest
- I have columns for email, Surnames of Common Ancestors, testing company, Contact
person, Send/Receive dates, Comments
- GEDmatch
- Download raw data from FTDNA or 23&me
- upload at www.GEDmatch.com (also upload GEDcom); include your name and email
- get more matches/segments, add to spreadsheet; send emails to them ALL.
- Note Common Ancestors for each atDNA segment
Phase III – Mapping Concepts
- Phasing
- Each parent gave you one set of Chr (01 to 22)
- Any segment match could be from either parent
- Phasing is determining which parent for each segment
- Easiest if you can atDNA test each of your parents - then use program at GEDmatch
- OR Common Ancestors will indicate which phase (CA is from which parent)
- Overlapping Rule – 2 overlapping segments will:
- EITHER be from same ancestor of one parent
- OR be from two ancestors, one from each parent
- If matches with overlapping segments match each other:
- All of you are probably from same Common Ancestor
- Check your segment map, look for overlaps
- Contact them and ask: Do you match others? Do you know Common Ancestor?
Summary - The Answers:
Matching DNA means Common Ancestor
DNA covers specific lines or entire Ancestry
atDNA segments come from Ancestors
DNA is a TOOL; use it with paper trails and other Genealogy Tools
You still do the genealogy work!
DNA is powerful and ~100% accurate
Just DO IT!
106739097 9/1/2012 [P a g e | 4]