Our Shared DNA feature is a chromosome browser. This is a tool which can be used to view and explore which parts of your genome are shared with a specific match, and which parts are not.
Most humans have 23 pairs of chromosomes (although this is not always the case, as with conditions such as Down Syndrome or Turner Syndrome). One chromosome in each pair is inherited from your mother, and one from your father. Because of a process called ‘recombination’, they are not inherited neatly, but rather jumbled up and formed into a new pair that is unique to you.
We use the 22 autosomal chromosomes to provide you with your matches - the 23rd chromosome isn’t used for this service - and each of the 22 chromosomes that make up your autosome are represented by a single row. Dark blue segments highlight where on each chromosome you and your match have the same DNA, and each segment may be present on one or both copies of your chromosome.
When you click on a shared segment, you will see information about the segment length, including where on the chromosome it starts and ends.
There are also some striped areas on some of the chromosomes, in addition to the blue shared segments. These striped segments represent parts of your DNA that are non-specific, and can be shared between people who aren’t related. It’s important to note that while shared segments overlapping these regions are included in the cM total, they haven’t been used to estimate your relationship distance.