Hacker News Reader

Comment by divbzero | Hacker News Reader

> “The findings suggest that life’s eventual homochirality might not be a result of chemical determinism but could have emerged through later evolutionary pressures.”

Homochirality resulting from chemical determinism would be the more surprising result to me.

The straightforward explanation is that random perturbations early in the evolution of life broke symmetry and led to homochirality of all descendent life, similar to how random perturbations early in the life of the universe broke symmetry and led to our world being made of particles instead of antiparticles.

View on HN

>The straightforward explanation is that random perturbations early in the evolution of life broke symmetry and led to homochirality of all descendent life, similar to how random perturbations early in the life of the universe broke symmetry and led to our world being made of particles instead of antiparticles.

Straightforward (and plausible) are not the same as true. Random perturbations are a parsimonious explanation, but a deeply unsatisfying one. With respect to matter vs antimatter, my understanding is that this remains an open research question in physics.

> Random perturbations are a parsimonious explanation, but a deeply unsatisfying one.

Why? I've always found it satisfying - it matches with how a lot of other things in biology has happened.

The universe has no obligation to be satisfying to you or me. Seeking explanations that feel good at the expense of parsimony is veiled numerology, not science.

Given how much of the rest of the chemical processes of life seem to proceed fairly straightforwardly from the rules of chemical structure and energy requirements for various reactions, I’d almost expect the opposite - that there’s some structure or reaction core to life that’s marginally cheaper or easier with left chirality that caused the divide, and the rest is history.

It's still not obvious how they could be separated at all by pre-biotic processes. You need to go from (in principle anyway) a pretty well-mixed 50-50 mixture to basically only lefties. I believe this is still one of the bigger problems for abiogenesis, and frankly I think you're being too glib about the antimatter problem too. I expect we're eventually going to find out about specific mechanisms that cause those.

A very plausible explanation is that the separation was biotic

There's a bootstrapping problem, though.

Not at all, think about it

Reply on news.ycombinator.com