Eradicating all disease is a laudable goal and understanding the genetic basis for disease is an important part of this effort. However i think it is extremely unlikely that this would be achieved by making people more genetically similar. On the contrary a high degree of genetic diversity in a population gives greater robustness against disease. Biology is a complex system and there are normally several ways by which it can compensate for any given problem (multiple pathways that do similar jobs and can take over if one fails).
The question, “if people become more genetically similar would they become less unique?” is very interesting, I think this is true to some degree, i.e. if all peoples genome were exactly the same, they would likely look rather similar and have similar baseline susceptibility to certain diseases etc, but there is proportion of phenotypic variability (peoples characteristics) that have an environmental component. This is the so called G x E (Genetic times Environment) effect and different genes (or variants in genes) are influenced more or less by environmental changes (some genes/variants are effected more than others by a change in environment). This is an active area of research, but is rater hard to study in humans (you can not control the environment in humans).
There would still be plenty of differences, I think, but this is really a question that we need to answer together as a society. There are plenty of genetic diseases that I can’t imagine anyone wanting to keep, but where do we want to draw the line between ‘diversity’ and ‘in need of a cure’?
I don’t see that eradicating disease would make people more similar. If anything it would have the opposite effect. Disease is a potent agent of natural selection which acts to reduce the genetic diversity in a population.
Interestingly, humans are very genetically non-diverse population compared to many animals. This is because modern humans originated from an African population only a few hundred thousand years ago and haven’t changed much since then. We do see some differences since then like skin colour, but not many compared to most animals.
One interesting thing here is that humans are pretty genetically similar. We’re quite a young species, and as we spread through the world there were always a few people moving between groups and finding mates in a new place. Obviously there are some genetic differences between us, like the genetic diseases which the question alludes to – or differences in hair or eye colours, or natural selection for paler skin in populations who moved to Europe. But on the whole we haven’t had a lot of time to diversify, and we’ve kept gene flow going between different populations. There’s more genetic variation between chimpanzees than there is between humans.
But as Tomas said, we probably wouldn’t want to be genetically *identical*, because we’d all have the same susceptibility to infectious disease, so one outbreak of a particular bug could kill us all. This has been a big problem for crop plants which we’ve bred to be genetically identical. Check out how worried banana growers are about a fungal disease called Panama wilt – most of our bananas belong to a single clone and if the fungus can kill one plant, it can kill them all.
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Freya commented on :
One interesting thing here is that humans are pretty genetically similar. We’re quite a young species, and as we spread through the world there were always a few people moving between groups and finding mates in a new place. Obviously there are some genetic differences between us, like the genetic diseases which the question alludes to – or differences in hair or eye colours, or natural selection for paler skin in populations who moved to Europe. But on the whole we haven’t had a lot of time to diversify, and we’ve kept gene flow going between different populations. There’s more genetic variation between chimpanzees than there is between humans.
But as Tomas said, we probably wouldn’t want to be genetically *identical*, because we’d all have the same susceptibility to infectious disease, so one outbreak of a particular bug could kill us all. This has been a big problem for crop plants which we’ve bred to be genetically identical. Check out how worried banana growers are about a fungal disease called Panama wilt – most of our bananas belong to a single clone and if the fungus can kill one plant, it can kill them all.