This TED Talk features chemical biologist David R. Liu, recorded live at TED 2019.

The most important gift your mother and father ever gave you was the two sets of 3 billion letters of DNA that make up your genome.

But like anything with 3 billion components, that gift is fragile.

Sunlight, smoking, unhealthy eating, even spontaneous mistakes made by yourselves all cause changes to your genome.

The most common kind of change in DNA is the simple swap of one letter or base, such as C,

with a different letter, such as T, G, or A.

In any day, the cells in your body will collectively accumulate billions of these single-letter swaps,

which are also called point mutations.

Now, most of these point mutations are harmless, but every now and then, a point mutation disrupts an important

capability in a cell or causes a cell to misbehave in harmful ways. If that mutation were inherited

from your parents or occurred early enough in your development,

then the result would be that many or all of your cells contain this harmful mutation.

And then you would be one of hundreds of millions of people with a genetic disease,

such as sickle cell anemia or perjuria or muscular dystrophy or tasax disease.

Grievous genetic diseases caused by point mutations are especially frustrating because we often

know the exact single-letter change that causes the disease and in theory could cure the

disease. Millions suffer from sickle cell anemia

because they have a single A to T point mutations in both copies of their hemoglobin gene.

And children with progeria are born with a T at a single position in their genome where you have

a C,

with the devastating consequence that these wonderful bright kids age very rapidly

and pass away by about age 14.

...