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Your DNA — a Self Testing 101
Your DNA is a string of protein pairs that encapsulate your “build” instructions, as inherited from your birth parents. While copies of it are packed tightly into every cell in, and being given off, your body, it is of considerable size; a machine representation of it is some 2.6GB in length — the size of a blue-ray DVD.
The total entity — the human genome — is a string of C-G and A-T protein pairs. The exact “reference” structure, given the way in which strands are structured and subsections decoded, was first successfully concluded in 2003. It’s absolute accuracy has gradually improved regularly as more DNA samples have been analysed down the years since.
A sequencing machine will typically read short lengths of DNA chopped up into pieces (in a random pile, like separate pieces of a jigsaw), and by comparison against a known reference genome, gradually piece together which bit fits where; there are known ‘start’ and ‘end’ segment patterns along the way. To add a bit of complexity, the chopped read may get scanned backwards, so a lot of compute effort to piece a DNA sample into what it looks like if we were able to read it uninterrupted from beginning to end.
At the time of writing (July 2017), we’re up to version 38 of the reference human genome. 23andMe currently use version 37 for their data to surface inherited medical traits. Most of…
