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Chromosome browser

From ISOGG Wiki

A chromosome browser is a tool that provides a visual representation of one or more chromosomes.

Autosomal DNA

In autosomal DNA testing the term chromosome browser is used to describe a tool which allows the user to do a comparison between one or more matches to see which segments of DNA are shared in common and the locations of the shared segments. The browser provides a graphical view of the half-identical segments shared with the match or matches on each individual chromosome. Matches can be on the paternal or maternal chromosome but the chromosome browser cannot distinguish between the two.

Some chromosome browsers allow the user to view fully identical regions – segments of the chromosome which are identical on both the maternal and paternal chromosome.

FamilyTreeDNA provides a chromosome browser with their Family Finder test. The browser displays half-identical segments only. For instructions on using the FTDNA browser see the articles in the FTDNA Help Center Chromosome browser introduction and Chromosome browser guide. Examples of comparisons using the FamilyTreeDNA chromosome browser can be seen in the article on chromosome browser examples though note that these examples are based on an older version of the chromosome browser.

23andMe provides a chromosome browser which displays both half-identical and completely identical segments. The tool is known as the DNA Comparison Feature. To access the browser click on someone in your DNA Relatives match list. There is a dropdown arrow labelled "View DNA Details" below the family tree structure in the "Your genetic relationship" tile. If you click on that, you will see a one-to-one chromosome browser of you and that match. The browser can be also be accessed under Family & Friends/Advanced DNA Comparison. Select relatives to include in the comparison. Then click "Compare". Full instructions for the use of this feature are provided in the Customer Care article DNA Comparison Feature.

MyHeritage provides a chromosome browser which can be accessed from the DNA Tools menu. The MyHeritage browser displays half-identical regions only. You can select up to seven matches at a time to compare segments. See the article in the MyHeritage Knowledge Base How to use chromosome browsers for genealogy. At MyHeritage there is an option to disable sharing of segment data which means that the segments will not display in the chromosome browser for those who have opted out. See the FAQs What are my privacy options for my DNA data?

A chromosome browser is also provided by the free third-party websites GedMatch and GeneaNet. Both browsers display both half-identical and fully identical segments.

Y-chromosome DNA

ISOGG has a human Y-chromosome browser known as YBrowse which can be used to examine SNPs in different regions of the Y-chromosome. YBrowse is based on Human Genome Version 38 (hg38; Genome Reference Consortium GRCh38). The browser is maintained by Thomas Krahn.

It is also possible to explore Y-chromosome next generation sequencing data by using one of the many available genome browsers. See the Wikipedia article on genome browsers for an extensive list.

Further reading

See also