Tag Archive | DNA tools

A Nice New Feature at DNApainter.com

Jun28

One tool I use all the time at the DNApainter site is the online shared cM calculator. This shows you the possible relationships that you have to a DNA match based on either the shared centimorgans (cM) or the percentage of DNA shared. It uses both the calculated odds from the DNA geek and the observed odds from Blaine Bettinger’s shared cM project. I find that these are far more useful than the predictions at the various testing companies.

Results of the online calculator for cousin “C’ sharing 1158 cM, red arrow points to new feature

When you input a number in the box at the top under the word Filter, you get a display like the one above which shows the likelihood of various relationships. Additionally those possibilities have their boxes light up in the chart underneath (click the image for the larger version which shows that). I used the 1158 cM that my first cousin “C” shares with me, on the high end for that relationship, to see what would show.

Do you see my red arrow pointing to the new feature? When you click on the words View these relationships in a tree you get a diagram like the one below, showing possible places for you in the tree of your match. Quick tip, right click those words to get a little menu from your browser letting you open it in a new tab or window. This diagram is created by the WATO (What Are The Odds) tool.

WATO image for C

WATO for cousin “C” showing the menu for editing her in the tree (click for larger version)

One thing that takes getting used to for many of us genealogists, is that WATO uses a backwards pedigree format, a sideways descendant tree. The presumed common ancestor is on the left and the descendants fan out on the right. Every person in this diagram can be edited by the way. You can add names, birth years, whether they are half relationships, and so on.

Most people like visual displays of relationships so it is great to see the possibilities laid out in a family tree. Click the Continue Reading below for my experiments with some of my known cousins. However you may prefer to read about the details of this new tool by its author, Jonny Perl, on his blog (click here) – he does a great job of explaining it.

Also to learn more about WATO, click here for the Family History Fanatics youtube video or click here for Leah Larkin’s many more advanced articles on WATO.

Continue reading →

New DNA Tools and Blog from a Scientist at Cornell

Nov5

Much of the work to build tools and write articles to help testers with their DNA results has been done by citizen scientists, bloggers, computer programmers, and scientists from other fields like Andrew Millard (behind the WATO math). In an exciting development, Amy Williams, a computational biologist at Cornell University, has built a few DNA tools, with more to come, and started a blog at https://hapi-dna.org/blog/

Her blog article titled “How often do two relatives share DNA” is particularly interesting. It includes the beautiful chart shown below which is created from simulations. Click it to go to the actual page where you can mouse over the columns to get the detailed numeric breakdowns.

Chart of How Often 2 Relatives Share DNA from https://hapi-dna.org/2020/11/how-often-do-two-relatives-share-dna-2/

The other article on her blog has a detailed explanation of what a centiMorgan is, the measurement used for DNA segment sizes (click here). I usually recommend not worrying about the exact definition since it is a measure of the frequency of recombination rather than a physical length. It is important just to know that there is not a one-to-one relationship between the cM and the sizes shown in the chromosome browsers. On the those charts, the same cM amount looks smaller at the ends of chromosomes than it does in the middle because recombination is more active on the ends.

The final statement of that article is: “In an upcoming post, we’ll talk more about cM lengths of DNA and how recombination leads more distant relatives to share fewer segments that are also on average smaller than those that close relatives share.” Something to look forward to!

Now to take a look at the tools that are available there so far.

Of particular interest to adoptees is the maternal versus paternal predictor for half siblings or grandparents. I tried it out on a number of half sibling pairs who I have helped in the past.

Here is the prediction created for a brother and sister who share the same father but have different mothers, using the comparison of their segment data from 23andme:

However I discovered  number of minor usage issues when trying to use data from the different DNA testing sites.
Continue reading →

Great New DNA Tools in 2019

Dec31

2019 was a great year for DNA. Many wonderful DNA tools were created by the testing companies as well as by a number of third parties. Throughout this article I will list my blog posts which discuss the tools from 2019.

I have found so many new cousins thanks to ThruLines at Ancestry plus the deployment of that to my DNA matches. My current process is to sort my matches by date and then filter for just 4th cousins or better (or 15cm or better) to catch new matches while they are still logging in and so might see my messages. Also once a week I check my matches that have common ancestors to see if any new ones have been connected in (since I note how people are related in the notes, anyone with blank notes is someone I have not yet seen the tree connection for):

MyHeritage‘s Theory of Family Relativity also makes it easier to find new cousins. Many of my Norwegian cousins have been found there. I even got a message from one this morning!

23andme may be finally trying to consider us genealogists. They added a build your tree from DNA feature (yet to be blogged about here) and connected to the FamilySearch tree. My wish for 2020 is that they combine those features!

My favorite new 3rd party tools in 2019 are DNA2tree, a game changer for unknown parentage cases, and the addition of trees to the automated clustering at Genetic affairs. I confess, I actually bought myself an iPad so I could use DNA2tree.

Automated clustering really took off in 2019 with GEDmatch, DNAgedcom, and MyHeritage all adding clustering.

2019 also saw the birth of a new public database for Y and mitochondrial results at https://www.mitoydna.org/ (to be reviewed soon).

I have yet to cover all the great new tools at DNApainter.com although I refer people to the online relationship calculator there regularly.

Other new tools sites that I need to review are Borland genetics tools and Your DNA Family

2019 has been a really great year for DNA tools!