"Chromosome mapping is a technique used in autosomal DNA testing which allows the testee to determine which segments of DNA came from which ancestor. In order to map DNA segments on specific chromosomes it is necessary to test a number of close family relatives. Ideally one should test both parents, one of their children, and a number of first to third cousins on both the maternal and paternal sides of the family." (Source)
The above chart shows the matching DNA segments for adoptees I know about from Family Tree DNA and 23andMe, with those on my paternal side (matching my father or his brother) being on the upper half of each chromosome and those on my maternal side (matching my mother and her sister) being on the lower half of each chromosome. In the key, I've listed their initials, where the adoptee was born, the DNA segment lengths in centiMorgans (cM) and which of us the adoptee matches. By "mousing over" each segment on the output created (or by saving it as an htm file which can be re-opened), details of the segments are shown in the pop-out, including the segment length in cM and the start and stop locations along the chromosomes. As more cousins undergo DNA testing (I'm encouraging as many as possible), I'll fine-tune which branch of my family tree the various adoptees may want to focus on (and will add this to the key), and I'll keep adding to my Adoptee Chromosome Map as new DNA matches come in or as I find out that someone is trying to identify their biological family.
There are several excellent articles on chromosome mapping, including:
Chromosome Mapping aka Ancestor Mapping (Roberta Estes)
- Lesson 12: Chromosome Mapping (Kelly Wheaton)
- Chromosome Mapping (ISOGG), which provides the link for a detailed article by Tim Janzen and Emily Aulicino on chromosome mapping (Word document can be downloaded from Here) – if you want to get serious about chromosome mapping, you must read Tim and Emily's article.
I've recently added a new page to my website, Links for Newbies and Adoptees.
- Overlay... Window to the Past (8 Mar 2014) – The Genealogy through Google Earth blog started in January and I like the overall idea of what is covered, as I really need to start using Google Earth more for my only genealogy. This latest posting covers the use of overlays, which can be used to for showing, for example, an old map or old aerial shot on how things look today. Other blog postings include the use of Placemarkers in Cemeteries, Polygons for showing family land, and Paths for, say, showing migration routes.
- BBC Knowledge Explainer DNA (3:24) – Not a new You Tube video (although new to me), but it's a really great animation showing base pairs, recombination, etc. for those starting to learn about genetic genealogy.
- RootsMapper: Another FamilySearch Family Tree Extension (Ancestry Insider, 13 Mar 2014) – Gives details of a new extension from FamilySearch, RootsMapper (free) which shows your pedigree (or that for any other selected individual) in map format, animating backwards the migration of ancestors. The blog posting also mentions 2 other free FamilySearch extensions: FamilyMap (an iOS app), which doesn't give an option for anyone's relatives to be mapped except yours, and the amazing Puzzilla, which I featured in my last blog posting. For each of these, you need to have a (free) FamilySearch account.
- Your Family: Past, Present, and Future (Wait but Why, Jan 2014) – A really amusing blog posting with great diagrams showing numbers of ancestors, pedigree collapse, formula for number of distant cousins, etc.
- For the UK: 10 Best Free Historic Map Sites (Who Do You Think You Are Magazine, 12 Mar 2014) – for me the newly-released Ordnance Survey Maps - Six-inch England and Wales, 1842-1952 are amazing together with 86,000 Maps of Scotland, the earliest I noticed being from 1560 (both of these are from the National Library of Scotland).