On the Chromosome Browser page, the matching regions are half-matching DNA Segments that you share with your match. Each of your autosomal chromosomes comes [...]
Is it meaningful when two or more of my matches have a DNA segment or segments in the same location?
Yes. You may all share a DNA segment inherited from the same ancestor. However, you each inherited half of your DNA from each parent. [...]
If I have two matches with overlapping DNA segments, how will I know if they have those segments in common?
To tell if two or more of your matches have DNA segments in common, ask each to check for the other on their match [...]
The centiMorgan (cM) values for DNA segments are measurements of how likely the segment is to recombine as it passes from parent to child. [...]
The Family Tree DNA bioinformatics team works with centiMorgan (cM) data from the International HapMap project.
Current knowledge of centiMorgan values across the human genome [...]
Yes. Limitations in the number of global populations used and the number of samples tested in the International HapMap recombination rate studies limit what [...]