[HN Gopher] More and more humans are growing an extra artery, sh...
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More and more humans are growing an extra artery, showing we're
still evolving
Author : donatzsky
Score : 60 points
Date : 2021-08-26 18:54 UTC (4 hours ago)
(HTM) web link (www.sciencealert.com)
(TXT) w3m dump (www.sciencealert.com)
| benkuhn wrote:
| I'm not an evolutionary biologist, but it seems to me that the
| claimed magnitude of the change is wildly implausibly fast from
| an evolutionary perspective. I'm confused that neither the
| article, nor the paper it cites, addresses this.
|
| To go from 10% to 30% in ~5 generations, the median-artery-having
| population would have had to expand by (30/10)^(1/5) = 25% more
| than the non-median artery population over each generation. It
| just seems totally implausible that median artery carriers could
| have that much more offspring.
|
| This makes me pretty suspicious that the paper may be wrong.
| sxg wrote:
| I really dislike these articles on pop-sci websites. It's
| basically just another clickbait news site except it has the word
| "science" displayed everywhere to give itself slightly more
| legitimacy.
|
| This artery is just another normal variant. There are tons and
| tons of normal variants throughout the body including major
| central arteries (eg aberrant right subclavian, retropharyngeal
| carotids). The changing prevalence is likely more an artifact of
| data collecting than anything meaningful, just like most of the
| articles on these sites that gain any traction.
| [deleted]
| ozarkerD wrote:
| Given that there's so much technology available to keep humans
| alive, will human evolution continue? It seems like it could give
| rise to a lot of negative traits propagating that would usually
| mean death before producing offspring a couple hundred years ago.
| nradov wrote:
| Evolution will continue. It just won't be heavily influenced by
| our ability to survive in the natural world.
|
| One evolutionarily change I predict is that certain forms of
| birth control will become less effective over the next
| generations. Hormonal birth control isn't 100% effective and
| there's probably a genetic component to that. So the women for
| whom birth control doesn't work as well will tend to have more
| offspring and pass those traits on.
| thunderbird120 wrote:
| Evolution is the propagation of traits of individuals who
| survived and reproduced and whose offspring survived and
| reproduced. In a modern developed country survival is less
| uncertain but reproduction of healthy individuals is actually
| more uncertain as can be seen by looking at the birth rates in
| essentially any developed country. As a result, traits that
| affect certain behaviors, such as underlying desire to
| reproduce, are likely under more intense selection pressure now
| than any traits in all of human history.
| thaumasiotes wrote:
| > will human evolution continue?
|
| This is a nonsensical question; it isn't possible to have
| reproduction without evolution.
| echelon wrote:
| > This is a nonsensical question; it isn't possible to have
| reproduction without evolution.
|
| It's possible to have reproduction without evolution.
|
| We have monoclonal immunocompromised mice with fixed genomes.
| We created them.
| thaumasiotes wrote:
| You say that like clonal organisms aren't out in the wild,
| evolving. It is not possible to have reproduction without
| evolution.
| echelon wrote:
| Monoclonal mice aren't out in the wild. But more
| importantly, some of the lines are incapable of breeding,
| yet we keep making them.
| jl6 wrote:
| In general it's hard to make value judgements about which
| traits are positive and which are negative. Natural selection
| cares only for survival advantage of offspring in the immediate
| environment.
|
| A good example is sickle cell trait, which provides a higher
| resistance to malaria, but a risk of a variety of other
| complications. In areas where malaria is a severe threat, the
| survival advantage of the higher resistance outweighs the other
| drawbacks. Medical intervention such as administering a malaria
| vaccine might reduce the threat of malaria such that there
| would be selection pressure against the sickle cell trait
| instead of for it.
| woleium wrote:
| right, so without external pressure we get diversification,
| making a more resilient pool of phenotypes.
| idiotsecant wrote:
| No, it's showing that we maintain the extra artery. There is no
| reason to believe this is an evolutionary change - there are
| plenty of hormonal and other environmental factors that could be
| contributing as well.
| edgyquant wrote:
| I mean, how is that not potentially evolution?
| evancox100 wrote:
| Agreed, pretty clearly an epigenetic or environmental change,
| not an evolutionary DNA change.
| crazygringo wrote:
| Exactly -- if the rate of change is as high as they state --
| from 10% to 30% of people in a little over a century -- it
| seems it would be essentially impossible for it to be the
| result of natural selection or genetic change.
|
| As you say, the obvious explanation is hormonal/environmental
| factors.
| gpsx wrote:
| Yes - in order to have a change be that fast it would have to
| be something that makes those people dramatically better at
| surviving, like X-men type mutations, or reproducing. I don't
| think the change of this blood vessel is really turning the
| tables between survival and death, or making these people
| that much more successful at reproducing. But with the
| prevalence of online dating these days, maybe it is a big
| help by allow people to navigate faster? /s
| Osiris wrote:
| A mutation will also stick around if it doesn't prevent the
| person from reproducing.
|
| That can still be considered evolution even if it doesn't
| provide an obvious benefit.
| enkid wrote:
| What do you mean by environmental factors? The environment
| drives evolution, so changes in the environment would change
| who survives, which would lead to evolution. If it is an
| environmental factor that led to selection of individuals
| having this vein being more likely to propagate, that would
| still be evolution. This also some very simple scenarios that
| could lead to such a pressure, like the artery having some
| minor benefit in reproduction, but a disease we eradicated
| would disproportionately kill people with the artery.
| [deleted]
| OJFord wrote:
| They mean within a lifespan factors, like pollution, diet,
| lifestyle, etc.
| TrispusAttucks wrote:
| Evolution is of a change in the genes. Environmental
| factors can influence the expression of a gene (think
| Testosterone or Estrogen) without a change of genetics.
|
| The change in expression over time and participant count
| the study highlights is not compatible with a natural
| selection driven evolution.
| mrkramer wrote:
| Evolution is constant since environment we live in is always
| changing and we need to adapt to it. Extra artery is an
| anatomical variation[1] because in order to evolve random
| mutations are happening and whatever works is passed to
| offspring.
|
| For example this article[2] explains Alan Turing 's Turing
| pattern[3] and pattern variation of denticles, the toothlike
| protrusions that cover the skin of sharks.
|
| The article says "Nature tends to invent something once, and then
| plays variations on that theme." That's true because variation is
| a way for nature to trial and error certain solutions until good
| enough solution is found.
|
| [1] https://en.wikipedia.org/wiki/Anatomical_variation
|
| [2] https://nautil.us/issue/68/context/how-alan-turing-
| deciphere...
|
| [3] https://en.wikipedia.org/wiki/Turing_pattern
| jacquesm wrote:
| Of course we are still evolving. It's just that the selection
| pressures applied are different now than they were in the past,
| and this doesn't look like something subject to selection
| pressure so I doubt it is an example of evolution in progress.
| aksss wrote:
| This is about a condition called Persistent Median Artery or PMA,
| and it's a bit of a rabbit hole. Evidently having this condition
| is associated with increasing your odds or the impact of carpal
| tunnel syndrome.
|
| PMA can manifest in a few different configurations, like depth to
| which it extends in the hand, thickness, etc. Here's an
| interesting read with pictures of dissected forearms showing PMA
| variants. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6327784/
| kafkaIncarnate wrote:
| More and more people are also getting heart attacks. Coincidence?
| I think not! Evolution is selecting humans out!
| dylan604 wrote:
| I think human diet is selecting humans out. Nature didn't
| create food products, humans did. We took food, and created a
| product. How absolutely mind boggling dumb that just sounds to
| me. Food doesn't have ingredients; food are ingredients.
| bserge wrote:
| Only those who can live on a diet of McDonald's and soft
| drinks will survive!
| dylan604 wrote:
| I honestly wouldn't want to live in that world. Eating is
| something to be enjoyed not just to survive.
| [deleted]
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