Forearm artery reveals human evolution continues? • Hacker News Board

Re: Forearm artery reveals human evolution continues?

#11

Post by tronbabylove » Sat, Oct 10, 2020, 7:31 PM UTC

iheartblocks wrote: post #2

This seems rather dubious to me; what selection pressure exists that's increasing fitness for people with three arteries? The fact that it's progressing so rapidly suggests that this is either bad data, or environmental changes

I also find this shocking - 10% -> 30% seems like a massive change in ~100 years in the context of human evolution.

Why does increased blood supply create such a large selection pressure? And what type of surgical procedure uses the median artery as a replacement part?

I have zero training in biology, so I think my mental model must be very off.

Re: Forearm artery reveals human evolution continues?

#12

Post by fs_tab » Sat, Oct 10, 2020, 7:32 PM UTC

iheartblocks wrote: post #2

This seems rather dubious to me; what selection pressure exists that's increasing fitness for people with three arteries? The fact that it's progressing so rapidly suggests that this is either bad data, or environmental changes

If you're interested in the study or its methodology, you can request the paper directly from the authors at: https://www.researchgate.net/publication/344230933_Recently_...

According to the abstract, there has been a significant (p-value of under 0.001) increase in the prevalence of mid-arm arteries over time, which has been corroborated by multiple studies.

After removing studies that focus specifically on the evolutionary aspect of this change, the p-value is 0.018, which still suggests a correlation.

Re: Forearm artery reveals human evolution continues?

#13

Post by Someone » Sat, Oct 10, 2020, 7:32 PM UTC

dghughes wrote: post #4

ceejayoz wrote: post #3

Earlier quoted context omitted.

Right from the article: > Senior author Professor Maciej Henneberg who is also a member of the Institute of Evolutionary Medicine at the University of Zurich, Switzerland, says the median artery offers benefits because it increases overall blood supply and can be used as a replacement in surgical procedures in other parts of the human body.

>because it increases overall blood supply But that's what I want explained why is more blood beneficial for a person's forearm? I don't feel like I am lacking blood flow during my daily tasks in life. Can "extra arm artery mutant guy" out-compete me in a specific task so critical it means his genes are more likely survive than mine are?

I would guess extra blood flow could somewhat prevent people from suffering of cold fingers. I couldn’t find evidence for that, though.

Worse, Wikipedia claims it’s easier to commit suicide by slashing your wrists if you have this artery (https://en.wikipedia.org/wiki/Median_artery), and https://radiopaedia.org/articles/persistent-median-artery-of... says it can be a cause of carpal tunnel syndrome.

I don’t see how either could be an evolutionary advantage.

Re: Forearm artery reveals human evolution continues?

#14

Post by Retric » Sat, Oct 10, 2020, 7:33 PM UTC

carbocation wrote: post #10

The selection pressure on three versus two arteries feeding the hand has to be so incredibly small (in terms of survival to reproduction in humans) that I am having a hard time imagining how this story has any causal plausibility. Edit to be more clear about what in the article I'm responding to, it's this: > Dr Teghan Lucas from Flinders University says ... “This increase could have resulted from mutations of genes…

DNA isn’t so neat as to cleanly separate every change. Thus this could be related to a host of changes that collectively represent a noticeable advantage. With circulatory issues being the #2 killer in the US it’s likely for the circulatory system to be undergoing rapid change.

Increased blood flow to the hand may mean a more efficient circulatory system increasing athletic performance and lowering disease risks etc.

Re: Forearm artery reveals human evolution continues?

#15

Post by drbojingle » Sat, Oct 10, 2020, 7:33 PM UTC

Why would it stop?

Re: Forearm artery reveals human evolution continues?

#16

Post by Ericson2314 » Sat, Oct 10, 2020, 7:34 PM UTC

> Humans haven’t developed mutations or superpowers just yet, but a new study shows our species is still evolving in unique ways and changes in natural selection could be the major reason.

Ewwww. Why is university press the worst? If we are still evolving and this isn't just about genetic recombination then by definition mutations are involved.

Also the publicist writes

> This evolutionary trend will continue in those born 80 years from today, with the median artery becoming common in the human forearm.

Wat. "Evolutionary intertia" probably has been defined by someone, but it's not that.

It looks like this is a doubl-wammy misinterpration of the following quote, also from the press release:

> “This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually. If this trend continues, a majority of people will have median artery of the forearm by 2100.”

It could involve mutations and the trend could continue.

Re: Forearm artery reveals human evolution continues?

#17

Post by eecc » Sat, Oct 10, 2020, 7:35 PM UTC

carbocation wrote: post #10

The selection pressure on three versus two arteries feeding the hand has to be so incredibly small (in terms of survival to reproduction in humans) that I am having a hard time imagining how this story has any causal plausibility. Edit to be more clear about what in the article I'm responding to, it's this: > Dr Teghan Lucas from Flinders University says ... “This increase could have resulted from mutations of genes…

Well, Natural Selection doesn’t necessarily mean that only advantageous genes survive the Darwinian hustle, it can also mean that in the absence of negative external pressure also neutral variations are not systematically culled.

It’s like living in a civilized society; you don’t have to worry of starving tomorrow so you take on making art...

Re: Forearm artery reveals human evolution continues?

#18

Post by carbocation » Sat, Oct 10, 2020, 7:37 PM UTC

eecc wrote: post #17

carbocation wrote: post #10

The selection pressure on three versus two arteries feeding the hand has to be so incredibly small (in terms of survival to reproduction in humans) that I am having a hard time imagining how this story has any causal plausibility. Edit to be more clear about what in the article I'm responding to, it's this: > Dr Teghan Lucas from Flinders University says ... “This increase could have resulted from mutations of genes…

Well, Natural Selection doesn’t necessarily mean that only advantageous genes survive the Darwinian hustle, it can also mean that in the absence of negative external pressure also neutral variations are not systematically culled. It’s like living in a civilized society; you don’t have to worry of starving tomorrow so you take on making art...

Yes, I agree. I'm mostly responding to the authors' speculation:

> “This increase could have resulted from mutations of genes involved in median artery development or health problems in mothers during pregnancy, or both actually. If this trend continues, a majority of people will have median artery of the forearm by 2100.”

Re: Forearm artery reveals human evolution continues?

#19

Post by carbocation » Sat, Oct 10, 2020, 7:38 PM UTC

Retric wrote: post #14

carbocation wrote: post #10

The selection pressure on three versus two arteries feeding the hand has to be so incredibly small (in terms of survival to reproduction in humans) that I am having a hard time imagining how this story has any causal plausibility. Edit to be more clear about what in the article I'm responding to, it's this: > Dr Teghan Lucas from Flinders University says ... “This increase could have resulted from mutations of genes…

DNA isn’t so neat as to cleanly separate every change. Thus this could be related to a host of changes that collectively represent a noticeable advantage. With circulatory issues being the #2 killer in the US it’s likely for the circulatory system to be undergoing rapid change. Increased blood flow to the hand may mean a more efficient circulatory system increasing athletic performance and lowering disease risks etc.

I agree. There are plenty of reasons why this could be happening, including reasons that have nothing to do with any sort of selection at all. I've updated my comment to clarify what I'm responding to.

Re: Forearm artery reveals human evolution continues?

#20

Post by lehi » Sat, Oct 10, 2020, 7:46 PM UTC

> "Other examples of human anatomy changing over time, include the prevalence of spina bifida occulta (opening of the sacral canal), abnormal connections of two or more bones in feet, increasing absence of wisdom teeth, thyroidea ima artery (branch of the aortic arch) – decreased over time, disappeared completely by the end of the 20th century) and fabella (small bone in the back of the knee joint – increased over time)."

Many of these, and the headline artery, appear to be newly retained neotenous traits and/or atavisms. It reads similarly to a list of physical differences between domestic dogs and wolves.