or How to deal with all those DNA cousin matches

By Kitty Munson Cooper
Blogging at

My slides are always available at

One day I got an email from Mike who said I think my g-g-grandfather was the brother of your great grandmother Maren

My new 3rd cousin1R sent me photos of my g-g-grandparents Jorgen and Maren Wold which I had never seen before


Do I really have 1000 fourth or closer cousins?


But the number of children in each generation greatly affects this, my farming Norwegians usually had 8-10 children

You will not match all your 3rd cousins


but you will match all your 2nd cousins

and closer relatives

What percentage of your cousins will match your DNA?

Simplified version of the relationship chart from the ISOGG wiki (courtesy Dimario, Wikimedia Commons)

The "G" trick

The cousin level = the number of "G"s , else the greats plus one

If you are in different generations take the shorter path and the other is removed by the generation difference

Do I really have to look through thousands of matches?


Start with the low hanging fruit, "extended family" about 3rd cousins or closer

(75cM and larger)

Cousin Matches

  1. How much shared DNA in centimorgans (cMs)?
  2. Who else do they match?
  3. How many segments? (More than 2 is best)
  4. Closer cousins will have larger longest segments (20 cM or more, very important if endogamous,

When you contact a possible cousin give them as much information as you can. Offer them photos and stories ...

 Ancestry now divides your matches beyond your immediate family (parents, siblings) into close family (aunts, uncles, nieces, nephews, 1st and 2nd cousins down to 200cM), then extended family (down to 55cM) and finally distant. Plus they will divide them into parent 1 and parent 2. You can assign those parents if you know them

I indicate the actual relationship first thing in the little notepad on the match page which shows on the match list under the name

Cindy is actually the daughter of my first cousin who shares 1100 cM, so not surprising to share so much

Click on View match or the  name to get to the match page

where you can click on the number of cM for more of an estimate

There is an online calculator at

Enter the cMs and get probable relationships 


At Ancestry click on the plus sign (or pencil) next to the right of a match to assign it to a group with the color you choose

Start by creating a group for each great grandparent's line. I like to use warm colors for the maternal side and bluish colors for the paternal

Each color stands for a great grandparent line except on the Bavarian side where there are no testers at Ancestry

You need a good family tree for this!

Blue icon= ThruLines, Green= hint

A quick digression to show what you see when you click one of those icons

And if you click on edit your tree tags you get a side bar with the possible tags you can add or remove

How those tags appear on the profile

Ancestry has done a lot of the work for you by searching trees for common ancestors

Clicking Common ancestors will display only those matches with shared ancestors found via any tree on Ancestry

Since I always add a colored dot plus a note showing how I am related, I can quickly look through the matches to see if there are any new ones since they will not have a dot yet

Easier: just click both Unviewed and Common ancestors

Clicking on a match name or image on the DNA match list takes you to the match page for that person which will show the common ancestors when there are some

Clicking on a "Common Ancestor" brings up a display like this showing the relationship pathways (this feature is part of "ThruLines")

Click on Shared Matches to  look at the matches we have in common

Give each a dot for this family line (Munsons are green)!

Shared matches only show those who share at least 20cM

Clicking on the notepad makes a box slide in from the right where you can type notes like the actual relationship

(don't forget to click save!)

Click on the little icon to connect the match to that person in your tree via a panel that slides in on the right

Once a match is connected to your tree a little solid tree icon gets attached to their image on your match list

Typically when you log in you want to see your new matches,


if you catch them early they are more likely to respond to your messages

Personally I used to look at just 4th cousins or better who were unviewed and recent but then Ancestry added a centimorgan filter!

Another approach is to look for the descendants of a specific ancestor via ThruLines on your DNA home page

Unlike the Shared Matches feature, ThruLines finds even distant cousins


put your cursor on an ancestor on this page and see how many DNA descendants are here

So to check for Halling side matches I looked at Josephine's parents on the ThruLines page ... More matches than to her! So 6 Halling matches

Click on Peder

The ThruLines display for Peder Halling

click on any down arrow to see more

Click on the EVALUATE to see where the information is from the right column will slide in to show tree information

Ancestry explains why it thinks Anders is the son of Johanne and lists the family trees it used to determine that

But how do I copy this information to my tree?

Click on EVALUATE then click on the blue Next button which lets you pick a source, if a tree, more records 

Sometimes there will be a new ancestor in your ThruLines list, click on that to copy it

clicking on evaluate shows a side panel with 2 trees that have no records, very suspect, best to look for records 

click on the tree to use then you get a blue Add to tree button

Lets go back to Inga Olsen

We did add her to our tree, now to tag her and get more of her family added

To add more information about Inga, go back to the tree we copied from

To add a tag to a person click on the plus and tag

Click on her name to go to her profile in the other tree

then you can use Save to Tree to get her other family members copied over

Click on Tools then the + Save to Tree

Sometimes Ancestry can figure out the relationship from just the parents of your match!

One last tip: Click on your match's name on their match page to get to their profile and see whether they have logged in recently

MyHeritage has many ways to filter your results including by location and by bioancestrty

MyHeritage has many ways to filter your results even by genetic groups. You can combine filters that are in different menus

MyHeritage finds the relationships using the many trees

of its users and GENI; this tool is called the

Theory of Family Relativity (TOFR)

You can select just the matches with "theories"

click on Filters then All tree details then click Has Theory ...

MyHeritage matches are presented on card like boxes with much information and you can give them colored dots and stars

Melissa is a cousin I found at MyHeritage

Here is the MyHeritage theory, it only uses our two trees but many theories use multiple trees

An example of using multiple trees, in this case using the GENI world tree

To copy information over, start with the person who is in your tree

Look at the profile in your tree first,

Click on the box to get a popup where you can click the View profile or View in tree

If the match looks good then use Smart Matches to find the other tree

When you find the smart match to the tree with the information you want,

click Review Match

Look carefully and if it is a match click Confirm Match


That takes you to the page where you can copy facts and other people over

Click the < to copy a new fact over

To copy over a missing child, click the add as a new ...

A large selection of her relatives can be copied over as well

Not just new facts but different ones or "improved" ones can be copied

Don't forget to click save when you are done!

My free presentation from late 2020 about cousin matching at MyHeritage is posted on their FaceBook page - click here


Family Tree DNA

  • Takes uploads of other autosomal DNA tests

  • Has trees but no automatic tree matching 

  • Use the third party tool from GENETIC AFFAIRS to cluster and search trees for common ancestors

If they have posted a family tree the icon will be solid, else it will be lighter and an outline

Click on the family tree icon to 

see something like this

Family Tree DNA


  • You can email a match directly from the match list, no messaging system

  • If a match uploads a tree that is indicated and clickable

  • You can sort by largest segment, useful if your family is endogamous

  • The total cM are inflated since small segments are included so cut at a total 100cM and a longest of 20cM?


23andme has some excellent tools for searching your DNA relative list

At 23andme you can connect your online tree at another site to your profile for your matches to see BUT

it does not do any tree searching or matching of ancestors for you

23andme has an exciting feature, it predicts a tree from your matches (works less well with endogamy)

But if the tree recalculates you have to replace some of them

You can add names and people

Looking more closely, it predicts people who are descended from his grandparents and also from a set of great grandparents

Clicking an individual brings up a box where you can go to their profile or message them

Other sites you can upload your DNA to in order to find more relatives:

At GEDmatch the DNA relatives list is far from intuitive but it does include the email address and links to trees 

example of the Beta one to many comparison

Getting New Cousins to Respond to You

  • Have a family tree online
  • Upload friendly picture of yourself
  • Include details of who matches whom (they may have multiple kits)
  • Offer them information when you write to them

Do not be disheartened by lack of responses, some rarely log in 

Also the app for tablets and phones does not show the messages icon

Managing your Cousin Matches

  1. How much shared DNA in centimorgans (cMs)?
  2. Who else do they match?
  3. How many segments? (More than 2 is best)
  4. Closer cousins will have larger longest segments (20 cM or more especially if endogamous)

When you contact a possible cousin give them as much information as you can. Offer them photos and stories ...

All my presentation slides are online at

DNA for cousin matching -2024

By Kitty Cooper

DNA for cousin matching -2024

How to look through your DNA matches to find those real 3rd and 4th cousins

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