This post is the third in a series developed to support the Genealogical DNA Analysis Tool (GDAT) User Group at the Society of Australian Genealogists (SAG). It does not replace the extensive user guide and help video tutorials already developed by the GDAT team. Members of the User Group should always consult those resources first.
You can access Parts 1 and 2 by clicking the links below, or the user guide for more specific information.
Maximising the amount of pedigree information for your relatives (matches) within GDAT will greatly increase your success when using the genealogical tools. Remember that the product allows for additional data to be entered manually, plus you can always import GEDcoms generated from your own research to add pedigree information to a relative.
Tree Completeness and DNA Confirmation
There are two things you need to focus on if you want to be successful in working with the GDAT product to analyse your results using chromosome analysis. Firstly, you must have built your pedigree out as far as you can - the more complete your tree the more chance you will have of being able to identify shared ancestors with your matches. Secondly, you must be working on a solid DNA base. What I mean by that is - not only do you know who your ancestors are out to the second great grandparent level, but your DNA results also confirm them as genetic ancestors. The segments you share with your close cousins are the foundation of what you need to be able to 'walk back your segments' over time to more distant ancestors.
My aim is to identify and DNA confirm all my ancestors out to 5th great grandparents (254 ancestors). Chromosome analysis is essential for this exercise because as we go back in time, there is also a much greater chance that we are genetically related to our matches in multiple ways. These second relationships may well be back much further than we have researched for our own pedigrees or our matches. Due to the process of recombination past 3rd cousins, we don't always share DNA with all our genealogical cousins. This does not mean our tree is incorrect, it may just be that the DNA from that ancestor has not survived. However, in some circumstances our genealogical research may be correct according to the records but there is a genetic mismatch, where DNA reveals the parents may be someone completely different! Telltale clues for these cases are often that you have no matches on those lines.
I regularly take time to document my progress and monitor my results and this helps me to focus on priority areas. My progress for my own genealogy can be found on this page.
Before embarking on the resource intensive process of verifying your pedigree past 2nd great grandparents with chromosome analysis make sure you have:
- identified all your ancestors out to at least the 2nd great grandparent level;
- identified DNA cousin matches up to 3rd cousins that confirm that your 2nd great grandparents (P1-8 and M1-8) are also your genetic ancestors. These relationships can be confirmed provided you and your match share the appropriate cMs for the predicted relationship. Ideally, as many as possible of these close matches should have their results on a chromosome analysis site to enable you to build on these confirmed relationships and 'walk back the segments' to more distant ancestors using GDAT;
- used your DNA results to identify any unknown ancestors closer than 2nd great grandparents using the total cMs approach, if traditional research techniques have previously been unsuccessful;
- identified DNA matches for all your lines, with shared ancestors back to each of the 8 sets of ancestral couples at the 2nd great grandparent level. If not, reconsider whether the ancestors you have identified are actually the right ones? This will not always be the case, there are many reasons why you might have no matches, but more often than not it may be an indicator that either your research is wrong or the parent of your ancestor may be someone completely different;
- extended your pedigree out as far as you can - the more complete your tree the greater your chance of success in finding connections with your DNA matches!
Relevant Workspaces and Tools
As you work with the genealogical tools you will be predominately working in the following three GDAT workspaces, accessible from the main menu.
- Relative - views relevant to your DNA matches;
- Profile - views relevant to people whose DNA you are monitoring;
- MRCA - tools to assist your research.
The function keys in GDAT are very useful for navigation within the database. The most useful functions for genealogical analysis are:
- F2 - Relative Ahnentafels. To maximise your productivity, it is best to load pedigree information for your matches via a 'bulk import' from a third party tool as DNAGedcom. The F2 function provides the ability to add pedigrees manually via GEDcom import, Pedigree Thief and One2Tree (Windows only), plus you can also update details on existing ahnentafels already loaded to GDAT. Don't forget you can also upload GEDcoms extracted from your own family history program if you have researched your relatives ancestry, or just fill in the blank page!
- F3 - Family comparisons. This screen compares genealogical information between the profile and matches, identifying any common surnames. Highlighting the surname gives more information about your ancestor, so you can compare them to your matches ancestor list. If no surnames show for your match but they have an ancestor list, go back to the F2 screen, choose Update, then 'set relative lists to Ahnentafel values' and the missing surnames should populate.
- F5 - Merging. There are two main pathways I use for merging duplicate profiles. If you identify them in the F7 chromosome browser, highlighting the matches then right clicking will lead you to the F5 page. Or you can access the same F5 page via the Relative Menu. To complete the merge you need to remember to have the relative information you want to keep on the right. Tick boxes on the left if you want to retain that information. Things to keep an eye out for when deciding which relative to choose are - where Ahnentafel value = true, segments or status of MRCA are already assigned or if there are research notes. Always back up before a merge, so you can revert the database if the merge does not behave how you expected. In the case of duplicates, select the 'same person' radio button, then merge. There is also an option to select 'other' - this option can be used for combining relative records for closely related relatives. Check the user guide for more information.
- F7 - Analysis Tools. When reviewing matches in the F7 chromosome browser, highlighting the matches then right clicking will bring up a menu. The compare ahnentafel groups option will identify any shared ancestror couple names between the highlighted matches. Similarly, the compare ahnentafel surnames will identify any shared surnames within the match group. This can assist in finding possible connections between your matches.
The MCRA menu has some great genealogical tools that enable you interrogate the database in different ways and can be very useful in finding more genealogical connections.
- Segment MRCA's - This tool identifies matches whose status has been set to MRCA and lists them under the name of the MRCA group allocated to individual segments. It provides a good summary of each of the 'family group' names you have listed in the profile ancestor list (F6) and all your confirmed matches;
- Groups associated with MRCA's -This tool aims to find you more possible connections to your MRCA. For each of your family groups, it lists the group names of your identified and confirmed relatives back to the shared ancestors. Often these can be names little known to you. Investigating matches with these surnames in their trees can often lead to other descendants from these same ancestor groups. Because the group name is the same however, it does not always mean they are the same people, you need to do the research to confirm or reject them.
- ICW profile group - This tool lists relatives who have the same group names in their tree as the profile person, but have not yet been given the status of MRCA. These require investigation and can lead to identifying more shared ancestors. Whilst many of those with common names or listed as Unknown or MNU can be misleading, if you regularly use the MRCA notes field, the process can often bring to light other matches you may have previously investigated that should be revisited.
- Region clusters - This tool lists places names in common with the profile and their matches. Group name formatting needs to be consistent so not all your places will be listed if your match describes the place name differently. Can be useful for identifying matches from particular localities of interest.
The GDAT database won't find every connection, at times you will need to do research on your matches trees to find your shared ancestors. Remember to add new surnames and additional pedigree information to your relatives pages to maximise the effectiveness of the genealogical tools.
To get help:
* Make sure you first consult the extensive GDAT User Guide;
* Join the Facebook Group for GDAT and search the site to see if the question has been asked before. If not, ask the question there;
* SAG members can join the 'private' SAG GDAT User Group on Facebook for general collaboration between members.
* Back up regularly (under File);
* Use the available Help resources (under Help);
* If imports or views aren't behaving as you would expect, you probably need to adjust some of the defaults (under Preferences)
* Keep notes, one of the great features of GDAT is being able to easily pick up where you left off last time!
Finally....
GDAT is a complicated product, understanding how to use the product will take time and if you don't understand the principles of chromosome analysis then you will struggle mastering it.
Follow the 'Research Methodology' and make sure you have a solid 'DNA confirmed' base for your pedigree before you attempt to extend your confirmations past 2nd great grandparents using chromosome analysis. Genealogical and genetic research go hand in hand, just as we move from the known to the unknown using our traditional paper research methodology, the same applies with genetic research where we need to 'walk back the segment' over time.
If like me, you are looking to confirm your pedigree out to at least your 5th great grandparents then you will amass a great deal of genetic and genealogical data along the way. I started my genetic journey in 2010 and it's easy to forget some of that early research. I like to think of GDAT as my 'one stop shop', an easy way to manage all the data and minimise the amount of duplicated research. What I like most of all is being easily able to pick up where I left off if I haven't looked at a particular part of the family for a period of time. No research is wasted or lost and continues to build as more clues emerge, after all if you are into DNA chromosome analysis then you are in it for the long haul.
Thanks Becky Walker for providing this fabulous tool!
Veronica Williams
GDAT Group Convenor
2nd December 2022
