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thegagis t1_j1nl18o wrote

The number of alleles that can be found in the gene pool of the population.

Us Finns for example descend from a very small number of survivors of some ancient famine and each of our genes can be one of only the few alleles that those survivors happened to carry and no other alleles. Our gene pool is one of the smallest as a direct consequence of that ancient bottlenecking event.

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Ubermenschen t1_j1o6vxl wrote

How has that affected the normal day to day of life, if at all?

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thegagis t1_j1o927m wrote

We have a lot of type 1 diabetes and genetic propensity for coronary artery disease plus some unique inheritable diseases. The small gene pool combined with easily traceable diseases and really extensive church records of births going back many centuries means Finland is a gold mine for people who research human genetics.

I seem to have fortunately dodged both of the diabetes and CAD bullets.

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perta1234 t1_j1r2aau wrote

These are side effects of HOW Finns lost variation, and what variation was there in the beginning. This is not result of low variability itself, but impact of what variability was left. Basically inbreeding depression. A very slow population decline could result in quite different end result, more akin to purging less advantageous gene variant combinations out of the population.

Effect of low variability is that the population is slow in adapting genetically (by selection on existing variation). Need to wait for suitable mutations.

Generally, many inherited diseases are adaptations to other environments. I guess the last one I saw, was suggestion that many autoimmune disorders are related to survivability over plague.

[Added: By the way, Finns lack many genetic diseases that are common elsewhere]

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Jacquesatoutfaire t1_j1pou69 wrote

To piggy back on this, genetic diversity increases survivability of a population. The population of Finland before this ancient famine was probably much more diverse. The famine was a bottleneck event which only allowed the survival of a certain group of people with genetic and/or social [read: monetary] advantages survived.

Fast forward to some hypothetical future calamity/bottleneck event and, if diversity has not recovered enough, the entire population could die out if they don't have enough people with advantageous genes to survive.

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perta1234 t1_j1r33h3 wrote

By the way, famines used to be very common just 200 years ago, or even less. There were several per generation, also but not only in Finland. Basically that is why agricultural subsidy systems were created. Either there was way too little food or there was way too much food. Trade was not able to balance things enough.

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