11 May 2020
Setting it straight: Back to basics. It’s all in the DNA…sort of
Setting it Straight - Issue #6
Written by Nobel Laureate Professor Peter Doherty
Maybe you’ve paid $100 or more, ordered a kit, taken a mouth-swab, dropped that into the clear liquid in the tube provided, sealed it up and mailed it back to Ancestry DNA, LivingDNA, MyHeritageDNA, 23and Me, or one of the other commercial operations that analyse human genomes. Using strategies that depend on robotics and high-tech equipment, these “ancestral DNA” companies look at a million or so “sequencing snapshots” of the three billion base pairs aligned along the 23 chromosomes of the human genome.
They also check the mitochondrial DNA we inherit from our mother. Dad provides the sperm DNA that fertilises the maternal oocyte, while the baby gets an equal contribution of Mum’s genes plus a bit extra carried in the oocyte’s mitochondrial “energy machine.” Via that mechanism, all of us can be traced back to “mitochondrial Eve”, who lived about 200,000 years ago.