There are reasons to sequence an individual multiple times: tracking their microbiome, tracking the genetic evolution of their tumor, looking at gene expression, etc. There's not much value in sequencing someone's genome over and over again though.

Additionally, there's a lot more to sequence besides just human. Illumina does genotyping for agriculture, they supply 23andme and Ancestry with their SNP chips, sequencing for forensic applications, etc.

Agreed. The somatic genome changes a tiny amount every cell division (1 miscopy per 100 million bases) due to spontaneous mutations, gene expression and occasional recombination. These may be useful for diagnosing disease and determining effective drug treatments.

> There's not much value in sequencing someone's genome over and over again though.

There's plenty of value to each custodian that gets their own copy though, just like every cloud company wants their own copy of your name, email, and physical address.

Sure, but IMO it would be silly for another player to sequence you again rather than negotiate access to the data.

Ah, I see you're not in medicine. Physicians will repeat studies of arbitrary cost at the drop of a hat.

But in those cases, they are actually looking for changes. For germline WGS there are no differences.

a) we generally don't have access to the records of any other health systems in the area.

b) we generally assume the older data is stale. In the case of omics: did they keep the unaligned reads? What version of the genome was it aligned against? Was it a graph alignment? What depth? Did my geneticist approve of this methodology? The SNP evaluation? The variants? This goes all the way down. They'll question what generation of instrument produced the data, the duty cycles on the instrument, and on, and on, and on.

It'll be interesting to see if other things are sequenced as well. Histone mapping comes to mind. Histones are responsible for packing the DNA and exposing different segments. This is one major factor in why we have some many different types of cells with the same DNA.

You could also sequence bacteria, viruses, tumors, and many many more. It could also impact agriculture as well. Once sequencing becomes cheap enough, I think it'll extend far beyond a one and done test per person.

Isn’t the genome data of millions of people worth something? I am sure they will figure out a way to make tons of money out of that.

Population sequencing projects have already starting popping up. The prototype is the 100k Genomes Project in the UK

https://www.genomicsengland.co.uk/about-genomics-england/the...

and there are many other similar efforts underway.

I would be more confident to share my DNA with NHS than a Silicon Valley startup.

There are 7 billion people.$100 a test is a $700 billion market. Sounds pretty good to me.

Fun fact: that's slightly less than the DoD's annual budget.

I wonder if DNA can change later in life through some mutation or gene expression.

Your germline doesn't change. However you can acquire somatic mutations.

Plenty of epigenetic changes though. It's all about the multi-omics these days.