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From SNPedia

Genomic similarity[edit]

Shows pictures which highlight regions of similarity and difference between the two genomes. This can illustrate family relationships and patterns of genetic inheritance. For each chromosome there are 2 images created.

F1 self.png F1 parent child.png F1 unrelated1.png F1 sibling.png
self (or twins) parent-child unrelated siblings
Comparing a genome against itself results in a solid baby blue. Fully identical A parent compared to a child. Dark blue is a half-identical region Two unrelated people have a sprinkling of red across the whole chromosome Two siblings show alternating bands with and without red. Regions with red were not inherited the same parent, regions of solid blue are identical.

The Rectangle[edit]

One is a rectangle with size determined by the number of SNPs which were genotyped on that chromosome. Each SNP is presented in order in a pattern which 'snakes' so that the string 0123456789ABCEFH would be written as


This method for visualizing DNA is simple to explain, but it can fool the eye. In the image above it would appear that 0 & B are as close together as 5 & 6.

The Other Shape[edit]

The other shape is a Hilbert Curve, which is a more complex way of laying down the DNA. It minimizes the false impression above. If you think you 'see' something in either image, it should be present in both images.

An analysis of twins using these images is at http://www.dailykos.com/story/2011/03/30/961626/-Our-Genome-Decoded-How-Companies-Like-23andMe-Are-Advancing-the-Field-of-Personal-Genomics

The Family Report Example[edit]

While promethease does not make it possible for you to generate this specific style of report, here is a report designed to illustrate all the comparisons between members of a family.

User:Corpas son has more information about this report

Each column is a person, as is each row. The cells of the grid represent the results of offspring between these two individual. The cells of the diagonal represent that individual having children with "themselves" (also known as self-pairing or self-mating). This may seem like an error, but Promethease is also able to work for non-human genomes. Plants can produce offspring via Self-pollination and this report style originated with work in plants. Even for humans it is one more way to look at and think about your own DNA, and in particular, about the concept of how many recessive alleles you carry.