Examples of Chromosome Mapping

  • See what a chromosome map looks like. 
  • See where the chromosome mapping information comes from. 
  •  Learn how chromosome mapping by end location number can help you map out an ancestor. 
  • See examples of chromosome tables and matching end location numbers. 
  • Learn how to map a surname.

Example of chromosome mapping.PNG

Shown above are matches for Surname Welles and Wells matching on chromosome 11, end location number 55878633. 

Mapping out a Surname begins with a surname search in family finder. (Autosomal DNA kit called family finder available from familytreedna.com) Next, search for a pattern of matching end location numbers on the chromosome table starting with 5 matches at a time. Be sure to click on the view in table format to make sure the end location numbers really do match. Every number must be identical for a good match and you must have a minimum of 3 matches to an end location number for it to be valid. Two matches can be a PLACE HOLDER if you are certain you have found a line. You can also add to the database any matches you have to this surname and end location number so long as you have found an ancestor with this surname in your tree or your matches tree. You only need one in that case. You can match visually, by looking for matching end location numbers in the chromosome table shown above or you can download and custom sort for end location number and chromosome number using Excel shown in the next example. This search resulted in a pattern of matching end location numbers for surname Welles or Wells. 

Welles match 1.PNG

Matching End Location Number for Welles. Cousin match # 1: End location 55878633

In the example shown above for surname Welles, matching cousin #1, a closer inspection will show:

Chromosome 11

Start Location: 46117127

End Location:  55878633

Centimorgans: 1.28

SNPs:  800

Ancestor of Cousin #1 is

James Wells of Baltimore born 10/29/1648. This Wells family has become disconnected from their ancestors. The matching end location number shows that they are related to other Welles by DNA and Surname. This is a biological DNA match.


Tip:  Matching to the start location is not a good method for chromosome mapping. The reason why is the start location number will change in relation to distance or cM when there is a valid match. The end location number remains consistent when a valid match has been found for a surname.


Welles match 2.PNG

Matching End Location for surname Welles. Cousin match #2 on chromosome 11 matches for the same end location number as cousin number 1. This is a pattern. This is how you map a surname. The surname must have at least 3 matching end location numbers with your cousins to be a valid map for that surname.


Cousin match #2 on closer inspection matches as follows.

Chromosome 11

Start Location 46718718

End Location: 55878633

Centimorgans: 1.24

SNPs: 700

Ancestor of Cousin #2 is:

Governor Thomas Welles born 1590. Governor Thomas Welles is a cousin and we have a shared or common ancestor. This means that the DNA segment found on chromosome 11 with the end location number 55878633 is the map for finding this Welles family. The common ancestor is the person who has passed down the DNA. The common ancestor I have with Governor Thomas Welles is Robert Welles Sr. born 11/06/1540. Robert Welles Sr. is my 12th GGF and he is also the common ancestor for my cousin whose ancestor is Governor Thomas Welles as he is Thomas's Father. My most recent Welles ancestor is Robert Welles Sr.'s Daughter; Jane (Welles) Baldwin born 1572. 

Notice the comparison between cousin number one and cousin number 2? The pattern for these two matches is that both matches are found on chromosome 11 and both matches have the surname Welles or Wells in common and both match on end location number 55878633. The difference between these two matches is the start location and the cM. This information can provide valuable clues. Notice that the cM with cousin #2 is 1.24 and the cM with cousin #1 is 1.28? That is because the common ancestor with cousin #2 was born farther back in time in the year 1540, but the biological DNA match with cousin #1 was born much sooner, in the year 1648. That is a difference of about 100 years.  There is also a difference of 100 SNPs (100 million base pairs of DNA) in this stretch of time. It is very useful to have this information because it can give you a time reference to look in for the time period when these two Welles and Wells family became disconnected from each other. It is only when more people look for and map out surnames that these missing pieces can be mapped out.


Welles match 3.PNG

Matching End Location for surname Welles. Cousin match #3 on chromosome 11 matches the same end location number as cousin number 1 and cousin number 2. Because there are a minimum of 3 matches for the end location number to the surname, this is a valid match and a valid map for this surname.

 Cousin match #3 on closer inspection matches as follows.

Chromosome 11

Start Location 46718718

End Location: 55878633

Centimorgans: 1.24

SNPs: 700

Ancestor of Cousin #3 is: Isaac Wells born 1598 at Welche's Dam Cambridgeshire England.  Isaac also has a broken tree but is a biological relative and matches cousin number 2 exactly on the chromosome number, start location, end location, centimorgan length and SNPs. Isaac Wells was born 1598 and Governor Thomas Welles was born in 1590.  They are close enough in age to be brothers but could just as well be close cousins.  The ancestors of Governor Thomas Welles came from the Stourton area and descendants settled in Connecticut. Isaac Wells came from Welches Dam and his descendants settled in Maryland. James Wells also came from Maryland. All three Welles/Wells match for the same end location number on chromosome 11. In the next illustration, an alternate method for mapping out a surname by end location number is done by downloading matches to Excel 5 at a time.

Matching End location Numbers for Welles in Excel.PNG

How to find a pattern of matching end location numbers using Excel.

To get to this point, where you can map out a surname by end location number is fairly simple, although a bit time consuming. Some people find it to be an enjoyable and very rewarding hobby.   To create a surname map, first study the "How to do Chromosome Mapping" choices. They consist of a one page reference guide, a detailed step by step slide show for beginners and a hit the ground running one minute 20 second video. Everyone learns at their own pace. Some people get it right away and others may take up to a year before it really clicks. It actually took about a year to put this all together and study the method before sharing it to make sure it really works and it works beyond my highest expectations. It has been well worth the time spent. The exciting part of doing this is that once you find a number pattern for a surname, you can map that name back as far as it goes or as far as records exist. To learn how to put together an Excel worksheet like the one above, please scroll up and click on the "How to do Chromosome Mapping" from the menu" and view the video.  When you download your matches 5 at a time into Excel, be sure to copy all your sets of 5 matches (if you have that many) into one spreadsheet and save it in Excel by the surname you are researching. Remember when custom sorting to ALWAYS sort by end location first, then by chromosome. That will make it easier to spot the pattern. If you do not have Excel you can copy and paste the chromosome tables into a free version of Word from openoffice.org. 

How to map out a surname copy.jpg

Surname Map for Surname Welles or Wells.

In the example above three different people were able to connect the Welles or Wells in their family tree by mapping the surname to the end location number. This method helps to piece together ancestors and those ancestors relationships to cousins who share those ancestors. Do keep in mind these very important things. 

1.  An end location number can be mapped to more than one surname but you will only match to an end location number if you share that ancestor either by pedigree and end location number or biologically by end location number.

2. An end location number can have more than one surname attached to it. This is because surnames have not been around all that long. If you map an end location number back far enough, you may find other surnames share it.  Those are biological matches, parallel matches and sometimes you can have both or more than two ancestors that match by that end location number.

3. People who do not have well developed tree's, going back only a few generations may think that this end location number is attributed to a more recent surname. If in doubt, always check the database and look for matches that show a common ancestor. Those matches carry more weight. Younger generations will carry the DNA of older generations. When you are mapping small DNA segments in the 1 cM (centimorgan) range, consider the common ancestor is probably going to be in a very ancient time range.

4.  End location numbers can be mapped to Haplogroup's, which is very exciting. Several instances of this have been found already. Be sure to check out the surname-list link above to see which surnames have been mapped to a Haplogroup.  Be sure to join the database so you can see if a surname or end location number you are working on has already been mapped out. It will save you a lot of time and provide valuable information. Be sure to add your own findings to the database so that others can help you and you can help others map out a surname and end location number in more detail.


Surname Welles above, also shows matches by end location number to surname Tudor, Pugh,  Ellis, Ellison,  Hooper, Croft, Wilson, Lovell, Jordan, Gunn, Kiger, Hudson and Lloyd. Wells or Wells has the most common ancestors and is the oldest found for this end location number so far. A lot of the younger generations have inherited this end location number. It will be interesting to see how many matches inherit it and where it may end up as in the oldest of matches. Indications appear to be pointing to a very old line from Wales. It may not be a coincidence that Welles sounds like Wales. It may very well have been a location name in antiquity.  If you were to draw a timeline of all the matches for this end location number in the database, you would find that Princess Margaret Tudor born 1498 and Cecily Willoughby Welles born 1429 are the oldest common ancestor found in the matches for this end location number.

This may mean that Welles is actually a Tudor if you go back far enough because autosomally, Tudor is an ancestor of Welles or simply shares the same end location number and both are coming from the same ancestor. This might be a Tudor like Rhys ap Tudor or someone even older. As more people join our project, more answers can be found to intriguing questions like this.  To join us in this quest please scroll up to the top of this page and click on home to become a member and get database access and be sure to join us for exciting conversations in our FB Group also found at the top of this page by clicking on the link. 


Chromosome Mapping of Ancient Bloodlines (c) 2016 Wanda M Pierce

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