While we tend to focus on life on a human scale, I learned that there’s a huge amount of DNA in a bucket of sea water.
Decoding and recoding life
To really read DNA accurately and understand it thoroughly, you need to be able to write it from scratch and make it live, Venter explained.
His sequencing the first diploid human genome (with the genes from both parents) last year showed there is much more genetic variation between humans than first thought. His current goal is to fully sequence 10,000 humans and bring the price for each sequence down to $1,000. With that data, his says, “We’ll begin to really learn what’s nature and what’s nurture.”“
Microbes make up one half of the Earth’s biomass.” Venter’s shotgun sequencing of open-ocean microbial samples revealed that every milliliter of ocean has one million bacteria and archaea and ten million viruses even in supposedly barren waters. Taking samples on a round-the-world sailing trip showed that every 200 miles the genes in the microbes are 85% different.
“Microbes dominate evolutionary diversity,” Venter said. Some 50,000 major gene familes have been discovered. Humans and other complex animals have a small fraction of that in our own genes, but the “microbiome” of our onboard microbes carry the full richness. Only 1/10th of the cells in a human are human; the rest are microbes. There are 1,000 species in our mouths, another 1,000 in our guts, another 500 on our skins, and those with vaginas have yet another 500 species.