3 ms·

What is the environmental pressure? Just a mutation by itself doesn't spread, there should be some advantage? Shouldn't there?

napoleongl 2y ago
It’s enough that there is no decrease in the success of the offspring really. They don’t have to be more successful, just not less.
- bhickey 2y ago
  Under Hardy-Weinberg equilibrium we wouldn't expect a trait to go from 0.1 to 0.3 in a large population in four generations. This suggests that the trait is subject to selective pressure. There are a lot of potential causes. In my estimation the two most likely causes— First, hitchhiking. The mutation could be near some other beneficial mutation. The closer genes together on a chromosome the less frequently they'll be separated by crossing over events. Second, it could have some other, presently unobserved cardiac effect that reduces infant or maternal mortality.
  - FrustratedMonky 2y ago
    My joke pet theory is that it helps with mouse control on PC's. We are living our whole life at a desk, it is providing extra endurance for clicking.
    - banish-m4 2y ago
      We should just evolve ALPS key switches instead of fingertips already. Within a century, we'll look like the Prometheus engineer pilot.
  - beacon294 2y ago
    IIRC we would see any trait spread into its equilibrium point unless selective pressure leaned on the scale. So, it could go from 0.1 to 0.3 simply because it's population equilibrium is there.
deckar01 2y ago
> Similar[ly] the prevalence of other anatomical features such as spina bifida occulta and fabella has increased over the last 2–3 centuries. Evidence indicates that changes in the natural selection pressures acting on these specific anatomical features could have caused microevolutionary processes, leading to the observed increases in prevalence rates. They seem to be suggesting that this is not necessarily an advantage. Modern medicine makes pregnancies with these genetic mutations more viable, so the dominance of the gene expression becomes a more significant factor than fitness.

napoleongl 2y ago

It’s enough that there is no decrease in the success of the offspring really. They don’t have to be more successful, just not less.

bhickey 2y ago
Under Hardy-Weinberg equilibrium we wouldn't expect a trait to go from 0.1 to 0.3 in a large population in four generations. This suggests that the trait is subject to selective pressure. There are a lot of potential causes. In my estimation the two most likely causes— First, hitchhiking. The mutation could be near some other beneficial mutation. The closer genes together on a chromosome the less frequently they'll be separated by crossing over events. Second, it could have some other, presently unobserved cardiac effect that reduces infant or maternal mortality.
- FrustratedMonky 2y ago
  My joke pet theory is that it helps with mouse control on PC's. We are living our whole life at a desk, it is providing extra endurance for clicking.
  - banish-m4 2y ago
    We should just evolve ALPS key switches instead of fingertips already. Within a century, we'll look like the Prometheus engineer pilot.
- beacon294 2y ago
  IIRC we would see any trait spread into its equilibrium point unless selective pressure leaned on the scale. So, it could go from 0.1 to 0.3 simply because it's population equilibrium is there.

deckar01 2y ago

> Similar[ly] the prevalence of other anatomical features such as spina bifida occulta and fabella has increased over the last 2–3 centuries. Evidence indicates that changes in the natural selection pressures acting on these specific anatomical features could have caused microevolutionary processes, leading to the observed increases in prevalence rates. They seem to be suggesting that this is not necessarily an advantage. Modern medicine makes pregnancies with these genetic mutations more viable, so the dominance of the gene expression becomes a more significant factor than fitness.