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Caesarean births 'affecting human evolution'

bbc.com

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Re: Caesarean births 'affecting human evolution'

#11

Post by ptaipale »

bambax wrote: post #7

> Historically, these genes would not have been passed from mother to child as both would have died in labour. How do we know that? As the name implied, Caesar was born this way, a little over 2000 years ago. It's likely the procedure is much much older, too. So what timeframe are we talking about? What we didn't know how to do 100 years ago was how to save mother and child once birth had begun and the baby's head ha…

It is probably just a myth that Caesar was born this way.

At the time, the mother most likely couldn't survive a section, because the resulting infections would kill anyone who had such surgery performed. And Caesar's mother lived to old age.

Re: Caesarean births 'affecting human evolution'

#12

Post by ptaipale »

3131s wrote: post #10
bambax wrote: post #7

> Historically, these genes would not have been passed from mother to child as both would have died in labour. How do we know that? As the name implied, Caesar was born this way, a little over 2000 years ago. It's likely the procedure is much much older, too. So what timeframe are we talking about? What we didn't know how to do 100 years ago was how to save mother and child once birth had begun and the baby's head ha…

> Also, from an evolutionary perspective it doesn't matter if the mother survives birth; it only matters whether the baby lives. Wouldn't it though? A mother that lives can go on to give birth to more children. Not to mention that a mother's survival might affect her child's chance of survival.

The previous comment was probably written in an extremely patriarchal context... a king's offspring would be taken care of even if the mother died. Though even there, the chances of being stabbed in the back might have been increased without motherly protection.

Re: Caesarean births 'affecting human evolution'

#13

Post by gambiting »

ptaipale wrote: post #11
bambax wrote: post #7

> Historically, these genes would not have been passed from mother to child as both would have died in labour. How do we know that? As the name implied, Caesar was born this way, a little over 2000 years ago. It's likely the procedure is much much older, too. So what timeframe are we talking about? What we didn't know how to do 100 years ago was how to save mother and child once birth had begun and the baby's head ha…

It is probably just a myth that Caesar was born this way. At the time, the mother most likely couldn't survive a section, because the resulting infections would kill anyone who had such surgery performed. And Caesar's mother lived to old age.

People have performed all sorts of surgeries for thousands of years, and while yes, the percentage of them getting infected and resulting in death was probably very high, it doesn't mean that every single surgery ended that way - in the end, people have been amputating limbs or getting wounded on the battlefield and surviving without any sterilization. So while it's rather unlikely, it's possible that Caesar's mother survived the operation.

Re: Caesarean births 'affecting human evolution'

#14

Post by SocratesV »

Going to potentially be controversial, but we need (might be a strong word here) genetic manipulation with strong ethical and humanist values attached to it (and a lot more knowledge).

If we are to deny natural selection its role, then we might want to still prevent people from passing on genes which effectively handicap them when they don't have access to certain facilities and technology. Prevention in this case is not eugenics, but gene manipulation/therapy.

Having said this, what we most certainly don't want is genetic standardisation (good path for extinction) and even the manipulation of genes, that seem to cause "problems" (today's problems might be tomorrow's cure), needs a deep understanding of implications, which at the moment we probably don't have.

P.S.: Hold the similar view regarding GMO in food.

Re: Caesarean births 'affecting human evolution'

#15

Post by gnud »

bambax wrote: post #7

> Historically, these genes would not have been passed from mother to child as both would have died in labour. How do we know that? As the name implied, Caesar was born this way, a little over 2000 years ago. It's likely the procedure is much much older, too. So what timeframe are we talking about? What we didn't know how to do 100 years ago was how to save mother and child once birth had begun and the baby's head ha…

Things I learned from QI: The word Caesarian does not come from Caesar, but from Cadere, meaning to cut.

Re: Caesarean births 'affecting human evolution'

#16

Post by Grangar »

SocratesV wrote: post #14

Going to potentially be controversial, but we need (might be a strong word here) genetic manipulation with strong ethical and humanist values attached to it (and a lot more knowledge). If we are to deny natural selection its role, then we might want to still prevent people from passing on genes which effectively handicap them when they don't have access to certain facilities and technology. Prevention in this case is…

I'm no evolutionary scientist, but haven't we as a species already denied natural selection long ago?

For evolution you need physical separation. With our level of globalisation that's not going to work.

Re: Caesarean births 'affecting human evolution'

#18

Post by curun1r »

throwawygybj wrote: post #5
tn13 wrote: post #2

Main stream journalists can not get science right. In the normal course of evolution women with narrower pelvis die a painful death while delivering a baby (or the baby dies). Thus the genes that give women a narrower pelvis do not get passed on. We can not let these women die this horrible death. This is a good outcome.

There's two sides to this coin. By allowing normally lethal genes to be passed on were likely to cause more death in the future. This is definitely something that should be screened and prevented, whether through gene editing, surrogacy, or just selecting for embryos that are either male or lack the undesired trait. Nobody has to die to voluntarily select this out of the population. The Jewish community has been on t…

Why should we avoid those genes? We have the technology to deal with the situation when it arises. What would be the problem with, eventually, all women giving birth by Caesarean?

There are plenty of other instances where our advancements have likely influenced our evolution. For one, the ease at which we can today travel between continents means that there's far more breeding between different races than we've ever had in human history. Should that be stopped? We also don't run/walk nearly as much as we used to thanks to harnessing hydrocarbons...should we continue to try to select for the long-distance running abilities that helped our ancestors kill animals for food during persistence hunting? And I'm betting that certain people are genetically more predisposed to catching measles, polio or any of the other diseases for which we've developed effective vaccines...would we want to make sure that those genes don't get passed on?

In short...why optimize for a world that doesn't exist? Unless you subscribe to a belief in a post-apocalyptic future where modern technology regresses and mankind is forced to live in a more primitive state, there's really no need for us to actively do anything...the magic of evolution is that it just happens naturally. Now, evolution can be an uncaring bitch to individuals, so there's plenty of reason why an individual would want to screen their offspring for certain genetic traits, but at the societal level, it's just swimming against a really strong current.

Re: Caesarean births 'affecting human evolution'

#19

Post by nitrogen »

Grangar wrote: post #16
SocratesV wrote: post #14

Going to potentially be controversial, but we need (might be a strong word here) genetic manipulation with strong ethical and humanist values attached to it (and a lot more knowledge). If we are to deny natural selection its role, then we might want to still prevent people from passing on genes which effectively handicap them when they don't have access to certain facilities and technology. Prevention in this case is…

I'm no evolutionary scientist, but haven't we as a species already denied natural selection long ago? For evolution you need physical separation. With our level of globalisation that's not going to work.

For speciation you need some kind of separation, which does now sometimes happen within a generation (e.g. one social group refusing to date another social group), but is very unlikely to persist across many generations.

Evolution by natural or sexual selection within a single species can still occur.

Re: Caesarean births 'affecting human evolution'

#20

Post by m_eiman »

Grangar wrote: post #16
SocratesV wrote: post #14

Going to potentially be controversial, but we need (might be a strong word here) genetic manipulation with strong ethical and humanist values attached to it (and a lot more knowledge). If we are to deny natural selection its role, then we might want to still prevent people from passing on genes which effectively handicap them when they don't have access to certain facilities and technology. Prevention in this case is…

I'm no evolutionary scientist, but haven't we as a species already denied natural selection long ago? For evolution you need physical separation. With our level of globalisation that's not going to work.

haven't we as a species already denied natural selection long ago?

No, how could we? We have influenced external pressures such as predators on our selection, at most.

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