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Imagine this scenario: A big nuclear disaster occurs and local population is exposed to a big amount of radiations. Of course, many die, but those who survive emigrate away from the radioactive area, to a place that has not been affected by the disaster. This happened several generations ago (let's say about 200 years). The "radioactive refugee" community has remained partly isolated from the rest of the population ever since. It is a widespread prejudice that their children are likely to be born with ugly illness/malformations. For this reason, "native" people are mostly ok with having business or friendly relations with them, but it's very rare to get a mixed marriage. We are now dealing in a kind of post-apocalypse world, where scientific knowledge is much more primitive than ours. My question is, how much is the "prejudice" only a prejudice? Considering all their ancestors have been exposed to radiation, is it reasonable to expect "faulty genes" to still show up in babies? Or by now there's been a sort of natural selection and they are on average as healthy as the rest of the population?

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  • $\begingroup$ The size of the isolated population might be a helpful statistic. Also, is your question from a evolutionary / biological view or a social? $\endgroup$
    – Gillgamesh
    Jan 30 at 16:15
  • $\begingroup$ For obvious reasons there is no historical experiece with people, but this is done regularly with domesticated plants and the induced mutations are fully expected to breed true. $\endgroup$
    – AlexP
    Jan 30 at 16:26
  • $\begingroup$ For future reference, please keep in mind that we allow one and only one question. It's literally a reason to close questions (click "close" and read "Needs More Focus"). Including your title, I count four reasonably distinct (thanks to ambiguity) questions. Remember, just one: reflected in both title and post body. Cheers. $\endgroup$
    – JBH
    Jan 30 at 23:41
  • $\begingroup$ @AlexP Have there been no studies among the descendants of Japanese survivors of Hiroshima and Nagasaki? Prejudice is easy. "They don't look like us!" has driven the erosion of hate since day #1. But I'm wondering if studies about the persistence of human defects have been done. (I know they've been done with plants due to the Tunguska event.) $\endgroup$
    – JBH
    Jan 30 at 23:43
  • $\begingroup$ @JBH: With common crop plants it is a routine procedure, done with the express goal to induce mutations, which are then evaluated with a view of getting useful characteristics. But humans reproduce much more slowly than maize. The studies of the descendants of the Hiroshima and Nagasaki (for example, Nori Nakamura, "Genetic effects of radiation in atomic-bomb survivors and their children", in J Radiat Res 2006) show no indication of genetic effects in the offspring of survivors, but more detailed molecular studies are on-going. $\endgroup$
    – AlexP
    Jan 30 at 23:53

2 Answers 2

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It does not work that way, and it does work that way

The study of animals in the Chernobyl Exclusion Zone shows that being subjected to elevated levels of background radiation over time...

Fibroblasts from bank voles inhabiting Chernobyl have increased resistance against oxidative and DNA stresses

Fibroblasts isolated from bank voles inhabiting Chernobyl nuclear power plant accident site show elevated antioxidant levels, lower sensitivity to apoptosis, and increased resistance against oxidative and DNA stresses. These cellular qualities may help bank voles inhabiting Chernobyl to cope with environmental radioactivity.

...makes you better at withstanding radiation and other DNA-damaging effects.

Huh, who'd have thunk it.

The concept is called Radiation Hormesis.

And the study above is not the only one that shows that living with constant elevated background radiation levels, is in fact not something that shows up in the statistics as partcularly damaging. And certainly not something that causes mutations in offspring, no matter what anti-nuclear activists and fiction tropes wish for you to believe.

However, you claim that these people suffred a severe acute dose, and then moved away from that.

Well, we have studies for that too, from a couple of very known events:

The atomic bombings of Hiroshima and Nagasaki

The "Hiroshima and Nagasaki Survivor Studies" does — in short show — that...

  • Survivors of the event — hibakusha — do show genetic damage, such as increased risk of cancer and similar illnesses.

  • Offspring of hibakusha do not show any signs of damage.

So...

  • If you live in elevated levels of radiation, in such a manner that you can survive, you generally do not suffer any ill effects. And it does not carry over to future generations.

  • An acute high dose either kills you quickly, or later, or causes bad health... but it does not carry over to future generations.

Hence, if it happened over two centuriues ago...

It is all prejudice

Unfortunately, such prejudice — and associated discrimination — is very real. The aforementioned hibakusha have been living with this prejudice ever since the bombings took place.

Hence this prejudice, although unfounded, is very realistic.

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    $\begingroup$ Thank you! This makes sense. Probably, the social isolation could lead to some degree of inbreeding and the inbreeding to some birth defect, thus reinforcing the prejudice. $\endgroup$
    – Ilma2811
    Jan 30 at 19:05
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    $\begingroup$ And the horses that are in decline? Not radiation. POACHING. Very hard to enforce! $\endgroup$ Jan 31 at 5:09
  • $\begingroup$ A thought for you, adequate prejudice against marrying and having children with a group sustained over any sufficient time-frame could plausibly result in natural speciation ;) $\endgroup$
    – Pelinore
    Jan 31 at 17:37
  • $\begingroup$ "...makes you better at withstanding radiation and other DNA-damaging effects." Would higher resistance to DNA damage and oxidation essentially cause them to live longer? Oxidation by free radicals is pretty much the main source of ageing, and DNA damage the source of cancer (and thus, ultimately, death). is it plausible then than the offspring of nuclear survivors could become noticeably, if not inhumanly longer lived? $\endgroup$ Feb 1 at 10:32
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Unfortunately, most likely outcome is nothing. In Hirosima and Nagasaki, there is nothing. Of course, terrible things happened after the explosions, and even many decades later (babies with serious disabilities, increased canceer and so).

In our DNA, continuously are happening various duplication errors and so is the foetal DNA. Their majority remains always invisible - a funny thing of the DNA is that most of them does nothing (at least we have no idea, what is does).

The little minority causes a dead baby, most often earlier as mom would know, she is pregnant. Only very few has a visible effect on a way, which does not kill the baby yet in its little cell-ball state. Most of them kill the baby later. Only a very few of them results a born human.

The majority of the DNA damages causes mental retardation, disabilities, early death. Our DNA has "weak spots" very damages manifest much more often, these result well-known genetical sickness (Down-syndrome is yet a friendlier one, probably you do not want to google for the harder, like Edwards-syndrome or muscular amyotropy).

I do not know such things, which could have been interpreted as an inheritable improvement on any way. Or... maybe... this might be one (3%-12% of the women can actually see 4 different base colors, that is a genetical modification requiring two different X-chromosomes, we males have only one X, so tetrachromy can not happen to us, instead we happily get various color blindness).

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  • $\begingroup$ @Aron Flagged as unfriendly, step over. $\endgroup$
    – Gray Sheep
    Jan 31 at 8:55

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