Massive genetic study shows how humans are evolving
nature.com
nature.com
On more controversial lines, see this http://www.biorxiv.org/content/early/2017/09/06/184853.1 study (N=280,000) that correlates specific genes with IQ.
2) Making it impossible/unbearably expensive for people with genes that are correlated with higher risk of whatever conditions to get health care/insurance.
We need to be really careful with how we talk about genetic insights as we gain more and more understanding, as well as what uses of that information we allow, or we're going to get ourselves into another period of atrocities justified by what boils down to eugenics. Perhaps not on the scale of genocide of entire populations, but still bad enough.
It's only a matter of time before a nation state starts spending a not-so-insignificant amount of money on IVF + DNA-based screening to start picking good genetic offspring for their populace. It's only going to start becoming more and more plausible the cheaper we make this technology.
Very awkward and important questions/decisions await us in the near future.
Are gene-modded babies going to have genetic compulsions that make them predisposed to propaganda and suggestion? Biological kill-switches?
There's a lot of good and a lot of bad that is going to come out of these technologies.
This hypothetical doesn't make sense in the face of robotics. If people are around, they are because they are useful.
Unless one sees all governments as benevolent agencies that are truly "of the people, by the people, and for the people", this is a distinction to be wary of.
You don't need DNA tests, or even knowledge of the concept of DNA, to participate in a genetic arms race. DNA tests were not necessary to produce dogs that would rescue drowning humans or cows that would produce incredible amounts of milk. They also aren't necessary to produce "good genetic" humans.
https://www.nature.com/news/chinese-project-probes-the-genet...
It is worth remembering that China is a highly ideological society with blinders and "PC" of its own, and is not entirely uninfluenced by Western priorities.
Keep in mind that eugenics, the "old school" version of genetic manipulation, is widely considered a failure, and has a nasty association with certain unsavory leaders that loom large in European/American history (the most notorious one being, um, Hitler). One can say that eugenics has that nasty issue of raw tribalism clouding any potential good judgement. Personally, I would consider the sordid history of eugenics to be a warning sign to everyone in regards to genetic engineering.
The other angle to bring up regarding genetic manipulation of humans, is that genetic manipulation of animals and crops, whether through the old school "selective breeding" or more modern techniques, have not been without unexpected big problems. At the very least, specific health problems have popped up in certain purebreds, and certain bred crops are far more vulnerable to being wiped out by single parasites (eg: our "perfect bananas" have this nasty tendency to keep getting wiped out by the Panama disease). Biodiversity is also the reason that in-breeding of humans is widely looked down upon.
The other ties with the former: it is not impossible for some unsavory leader to take some research, bastardize the science through blinders of tribal instinct, say "Ah! Gene X is the key to IQ!", and do some nasty tribal things "justified" by science. And in the end, get it quite wrong in the end due to lack of biodiversity.
It doesn't take much imagination to think of this scenario. Creating artifical super children that grow up inside a lab and get killed off when convenient is the most common staple in scifi books and movies involving gene editing.
What's more important? Basic human rights for all humans or competitiveness?
I think the US constitution is silent on the subject of genetic research.
> What's more important? Basic human rights for all humans or competitiveness?
If a nation is uncompetitive, it won't matter in the long term what it thinks about human rights, as that nation will will be out-competed by other natinos that are more competitive.
To which the response could be: "You can't perform logical reasoning? Must not have gene B!"
At every step of the way it becomes slightly more acceptable to push the boundaries just so slightly.
[1] Been the case for many decades now in the case of sickle-cell anaemia, this affects partner selection. In the last decade selection against mutations in BRCA1 and BRCA2 i.e the "breast cancer genes", has lead to searches for egg donors. Also, some people with history of severe depression that runs in the family are self selecting against child bearing (this selection is more common among females).
[2] This could even be pseudo-science at the beginning.
[3] Sperm and egg banks already allow for a crude version of this.
[4] Either natural or synthetic.
I'm not a biologist, but reading this sounds more like a few years till mass market, not the ominous "30 years" you hear when people really have no clue how long it's going to take :-)
If we define beautiful as having blue eyes and blonde hair, of course beauty is genetic! That's equally analogous to how we define intelligence and find it similarly heritable. More work needs to be done on the former before we can for sure talk about the latter.
Twin and adoption studies have never been reliable. They have ranged from dubious methodology to outright fraud such as in the case of Cyril Burt.
But this study takes a snapshot of a population, and looks at gene prevalence as a function of age. So what you see are not effects of reproduction, but rather on survival. It finds the Alzheimer's gene less in 70 year olds, because those with the gene are more likely to have died earlier, and thus not appear in the study.
Thus your statement "APOE-Alzheimer-propensity gene is a new gene" is likely not true. It is likely just as prevalent in the current generation as two generations before; just those individuals from two generations before who had it are more likely to be already dead.
So the study looks at how genes influence survival rates -- something that is very obviously related to evolution if it occurs before reproduction. If survival rates only depend on some genes in higher age, they have only small, second-order effects on reproduction (like a child being more likely to survive if it has healthy grandparents or parents).
(Disclaimer: I'm not a biologist, so take this with a grain of salt).
So wouldn't the study be: "Those carrying genetic disease have a tendency to die early(er)"? What does evolution have to do with it?
BTW, it's perfectly possible for a gene to be wildly successful from the evolutionary point of view, while at the same time killing its owner invariably by the age of 50. How would this study have classified such a gene?
Agree the study does look at genes influencing survival rates. I still don't see the link to the headline 'humans are evolving!'. Small second-order effects, okay, sure. So how about, 'Massive Genetic Study shows genetics affect mortality rates, plus maybe there's a small secondary effect on reproduction, who knows?'.
[1]. 83,000 (i) or 3,349 (ii) Alzheimer's deaths per year out of 2mm deaths (iii) => 1-3%
i) http://www.nydailynews.com/life-style/health/alzheimer-kills...
ii) http://www.alz.org/mglc/in_my_community_60862.asp
iii) https://www.cdc.gov/nchs/fastats/deaths.htm
[2] See graphs in paper.
But to demonstrate evolutionary change, they'd need data on occurrence of these alleles as a function of birth date, stratified by age. It'll take some time to get such data. Probably at least a few decades.
When considered in a population, mortality is a feature, not a bug. Actually, it seems like aging is an additional feature, not a constraint of our bodies. There are animals that seem to have "accidentally" deactivated it: Galapagos giant turtles, some species of shrimps and, I think, some naked mole rats. These animals seem to have enough causes of mortality to keep evolving, without the need of a timer.
This seems like a lot of speculative leaps to me.
1. assuming that they should necessarily find many of these correlations, absent evolutionary elimination (maybe the effects of individual groups of genes just aren't that strong?)
2. assuming that the lack of them indicates that they existed before and were eliminated (maybe they never existed at all?)
3. more generally, assuming that evolutionary selection is a determining factor in the data they're studying at all (I don't often see noticeable changes in a few generation in highly-contrived genetic algorithms I play with, let alone real-world data which has way, way more noise)
* tested more than 8 million common mutations, and found two that seemed to become less prevalent with age. A variant of the APOE gene, which is strongly linked to Alzheimer’s disease, was rarely found in women over 70. And a mutation in the CHRNA3 gene associated with heavy smoking in men petered out in the population starting in middle age. People without these mutations have a survival edge and are more likely to live longer, the researchers suggest.
* certain groups of genetic mutations, which individually would not have a measurable effect but together accounted for health threats, appeared less often in people who were expected to have long lifespans than in those who weren't. These included predispositions to asthma, high body mass index and high cholesterol.
* Most surprising, however, was the finding that sets of mutations that delay puberty and childbearing are more prevalent in long-lived people.
So the article and paper seem to be arguing that a low frequency of late-acting genes indicates ongoing evolution, but acknowledge that this raises questions about why natural selection would act on them.
The relevance of the decrease of the prevalence of these genes with age is apparently that survivorship bias is being used to distinguish causation from mere correlation.
So having healthy grandparents gives a survival advantage.
At that age, the effect should be reversed as people often need care themselves rather than caring for grandchildren (who may be adults by that time anyway)
I suppose the "grandmother theory" originally only explained why women live beyond menopause, not into their 70s, 80s or 90s.
Maybe even more importantly, though, 100 years ago other, unrelated diseases of old age were likely to get you well before Alzheimer's really got bad.
When resources get scarce, there are a lot of ugly realities.
http://newsroom.ucla.edu/stories/jared-diamond-on-aging-1505...
"Mostafavi and his colleagues tested more than 8 million common mutations, and found two that seemed to become less prevalent with age"
Old people are less likely to have this gene than young people. This can have two possible explanations: old people with this gene are more likely to are already dead (and thus not show up in the study), or the gene is becoming more prevalent in the younger generations. The statement "People without these mutations have a survival edge and are more likely to live longer" favors the first explanation.
This is not the effect of natural selection on gene prevalence. (And it would be weird for Alzheimer's, which usually occurs at an age where reproduction is often finished, and maybe even raising the kids is done already).
Note that they are not suggesting these genes have been the subject of selection; it is the hypothesized number of such late-acting genes that were not found that are assumed to have been selected against.
At least with smoking, we've been experiencing exactly that decrease for generations. Smoking has become vastly unpopular compared to how prevalent and socially accepted it used to be. Social factors had been one of the main driving forces, but that doesn't mean it has to be the only driving force.
As people live longer and safer lives, they can afford to have children later. And child mortality has been seriously reduced, so the children they have are comparable to thise among people from previous centuries who had many children younger.
Having children takes a toll on an organism, and having many children takes a larger toll, presumably. I wouldn't be surprised if there is a correlation between lifespan and number of children, among women.
So - people live longer and have children later. The children grow up richer and bigger and in turn have children later, as well.
I bet there is a correlation between age of having children and lifespan.
It stands to reason that postponing reproduction for as long as reasonably possible would contribute to selection for longevity. From evolution's perspective, you have to survive at least that long, or else you're not good for anything. If humanity collectively decides to postpone having children, evolution may begrudgingly allocate more of its resources toward the welfare of individuals, rather than viewing our early deaths as an acceptable loss in a cold utilitarian calculation about long-term gene proliferation.
(edits)
You could imagine a graph showing the percentage of pregnancies that occur at each age. The strategy would be to gradually move the percentages over time so that some percentage of sixteen year old pregnancies get shifted over into seventeen year old pregnancies, some seventeen year old pregnancies become eighteen year old pregnancies, and so on.
The goal is that, over time, there is escalating pressure to solve health problems that occur at later ages, problems that evolution currently has little incentive to address.
But dows that mean some sort of Lamarckian evolution is taking place after all?
Sexy son hypothesis is also similar. Is it related?
There is (at least for women).
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4270889/
> A significant association for later maternal age was found whereby women who had their last child beyond the age of 33 years had twice the odds of survival to the top 5th percentile of survival of their birth cohorts compared to women who had their last child by age 29 (OR=2.08, 95%CI 1.13; 3.92 for age between 33 and 37 years and OR=1.92, 95% CI 1.03; 3.68 for older age).
It's important to know though that delaying childbirth among women is associated with all sorts of other "healthy" factors like high education, high income, stable marriage, etc.
https://www.ncbi.nlm.nih.gov/m/pubmed/16510865/
But this study is contradicted by many studies
https://www.scientificamerican.com/article/having-sons-can-s...
Do children at 20-30 increase or decrease life span?
Obviously people who live longer may have more children, especially the men. I am talking about the other way.
Sometimes it's good sometimes it's bad. ¯\_(ツ)_/¯
From my own observations in middle school and high school, those that mature earlier are far more likely to get into drugs, forgo education, etc... all things that are measures of success in our current society
Smart people delay, wait and then end up not... "dumb" people just hook up and go to town...
I think the fact that Evolution is still spreading "successful" genes and "unsuccessful" genes become less prevalent is obvious.
What isn't obvious, is as Idiocracy so succinctly puts it, is that gene that are "successful" doesn't necessarily translate to intelligence, good decisions, stable lifestyle, etc.
This is a pretty clear social structure in humans. I understand not all or even most animals have that same social structure. Can someone explain to me why they would assume remaining alive after you dump off your genetic material would be neutral? (from an evolutionary perspective)
Why these late-acting mutations might lower a person’s genetic fitness — their ability to reproduce and spread their genes — remains an open question.
The authors suggest that for men, it could be that those who live longer can have more children, but this is unlikely to be the whole story. So scientists are considering two other explanations for why longevity is important. First, parents surviving into old age in good health can care for their children and grandchildren, increasing the later generations’ chances of surviving and reproducing. This is sometimes known as the ‘grandmother hypothesis’, and may explain why humans tend to live long after menopause.
Also "researchers scoured large US and UK genetic databases"- well, I wouldn't be too sure that the biggest part of evolution happening in the human species can be seen inside the UK and US genetic databases.
Considering the extraordinary amount of time it takes for evolution to do anything at all, that they can quantify it in what is relatively zero time in the span of life on Earth, seems to remarkable to be true.
http://discovermagazine.com/2015/march/19-life-in-the-fast-l...
As I understand, the simplest explanation for species being so stable over millions of years (like, say, sharks) is that while evolution can happen quite fast, it "averages itself out" - there's a kind of regression-to-the-mean effect.
That is part of what makes the report hard to believe, even if it is a novel idea and has some other merits.
Not to say it couldn't be true, but as I expressed, it seems remarkable that such evidence was found in a single generational study.
Either way my comment certainly wasn't intended as a critique aimed at you!
Also, thinking about it some more, it's not that strange that the idea of slow evolution hasn't died out yet, because it's not so much wrong as that reality more complicated and really counter-intuitive than what you think if you only look at fossils[0]:
> In the 1950s, the Finnish biologist Björn Kurtén noticed something unusual in the fossilized horses he was studying. When he compared the shapes of the bones of species separated by only a few generations, he could detect lots of small but significant changes. Horse species separated by millions of years, however, showed far fewer differences in their morphology. Subsequent studies over the next half century found similar effects — organisms appeared to evolve more quickly when biologists tracked them over shorter timescales.
> Then, in the mid-2000s, Simon Ho, an evolutionary biologist at the University of Sydney, encountered a similar phenomenon in the genomes he was analyzing. When he calculated how quickly DNA mutations accumulated in birds and primates over just a few thousand years, Ho found the genomes chock-full of small mutations. This indicated a briskly ticking evolutionary clock. But when he zoomed out and compared DNA sequences separated by millions of years, he found something very different. The evolutionary clock had slowed to a crawl.
(I have to apologise for not remembering this article yesterday, it would have made things more clear)
So in retrospect my "very stubborn idea" assessment is probably a bit unfair.
But, back to what we were taught in school. Caveat: I'm not a biologist, let alone evolution expert, just a nerd who is into this topic. There are a number of issues with the description you gave (which, for the record, fits with how it was taught to me in high-school)
It is true that evolution is not linear, but being taught that evolution is a stair step is just as bad. It (implicitly) assumes evolution is a form of progress. It's not, it's just adaptation. The simplest of life forms that exist nowadays are just as successful as we are, in the sense that they also didn't go extinct and will continue to thrive in the future. On the other end of the spectrum you actually can have runaway adaptation, especially when there's a kind of "arms race" between predator and prey. The cheetah is so hyper-specialised for catching its prey by speed alone that it's a kind of evolutionary dead-end; it can't zig-zag like the gazelle can. Anyway, the stair-step attitude originates from outside of biology, from Platonic thinking that there are "higher" ideal forms.
And the sudden changes turn out not to be "few and far between", they just don't seem to stick. Most adaptations average out, because they're highly contextual to their short time periods. As mentioned, since we based our first ideas about evolution on fossils, we only noticed the slow evolution. Sex actually seems to play a large part in the filtering process[1]:
> For a species whose numbers show no signs of collapsing, humans have a shockingly high mutation rate. Each of us is born with about 70 new genetic errors that our parents did not have. That’s much more than a slime mold, say, or a bacterium. Mutations are likely to decrease an organism’s fitness, and an avalanche like this every generation could be deadly to our species. The fact that we haven’t gone extinct suggests that over the long term, we have some way of taking out our genetic garbage. And a new paper, recently published in Science, provides evidence that the answer may be linked to another fascinating procedure: sex. (...) As the number of nasty genetic errors in a population rises, natural selection will sweep large rafts of them out of the genome together. And in sexual organisms, because of the ways that mutations from each parent can recombine randomly onto the same chromosomes, the synergistic elimination of bad mutations can happen even faster.
Anyway, hope this addresses some of your understandable scepticism!
[0] https://www.quantamagazine.org/evolution-runs-faster-on-shor...
[1] https://www.quantamagazine.org/missing-mutations-suggest-a-r...
I'm a little frustrated to point that out. However my frustration isn't enough to motivate my next question. What did you hope to accomplish, in light of these problems, by criticizing these scientists' work with what is ostensibly, cursory popular science knowledge?
I guess I just want to understand why there is a mistrust for professional scientists even on a site as technologically inclined as HN.
I think you are new to HN. There is a long history of healthy skepticism by the readers here of studies posted in a wide range of fields. Healthy skepticism, or at least, pointing out remarkable and hard-to-believe aspects of a reported study (as I did here), is quite commonplace all over HN.
In fact, if you read any of the nearly hundred other comments in this thread, you will see equal amounts of skepticism, some more verbose, some more terse, than what I expressed. Fortunately, you did not go and criticize those commenters also.
In the case of evolution, I was taught years ago in school that evolution is not a gradual and linear process, and that often very long stretches occur with zero evolutionary action, then a single evolutionary event causes a gigantic leap of changes in a species, a single spike, which then plateaus again for a long time another spike.
I am not an evolutionary scientist of course, but I was leaning on that, and layman's perception of evolution, in my comment.
I'm frustrated to have to point this out. What did you hope to accomplish by criticising my reaction to the article? Are we not all here to comment on our opinions and reactions to the items posted? Just because you do not agree with my particular reaction to the article does not mean you should make such wide assumptions about my own motivations (or those of any other reader you choose to attack in the future).
Imagine one that causes someone to be infertile. The balance of genetics changes (evolution) in a generation.
Africa went from 1/2 the population of Europe in 1950 to 1.6x the size today. The gene frequencies on those two continents are different - thus there has clearly been differential fitness (in the hundreds of millions in a lifetime)
A single isolated event with no impact on the species is not the definition that most would use for evolution. And even if it had an effect on that individual family, evolution is about nature selecting that particular mutation, which may not happen at all. So I don't support the premise of your argument.
I think what you are trying to describe is "novel fitness increasing mutations" - these won't be detectable for ages as it takes time to spread through a population.
Single isolated events matter - All mutations start off in an individual, they then increase or decrease in frequency.
Unless you have specific education in this area, this is contrary to the classes I took in university on the topic of animal biology. There is no "natural time period" for evolution, as you say. Meaningful change usually does not happen over any arbitrary period. It is typically a random event that spikes rarely in a species, and usually there are long periods of zero change until such spikes occur between these changes.
I suspect you are postulating on what evolution is without actually knowing how it most often emerges.
You are confusing two different but related issues, and may have misunderstood your professor. The timing of large effects (speciation, for example) is unpredictable, and there are long periods in the history of any given line of descent during which no speciation-level evolution occurred (note that the article is about evolution at a much smaller scale than speciation. These events are unpredictable in detail, but occur much more frequently.)
As for the process by which it happens - variation and natural selection - the generation is, to a first approximation, a characteristic unit of time. A mutation occurs at a point in time, but it is only subject to being selected by natural selection if and when it is passed in the next generation, and natural selection works by creating more of the next generation on account of it.
This is somewhat complicated by the appearance of neutral mutations, which do not have effects that are selected for or against. These take the genome on a continual but evolutionarily directionless random walk, for which the characteristic time period is the generation. There is the possibility that, as a consequence of these random walks, any given allele's frequency in the population will drop to zero, after which it will not reappear unless it is recreated by another mutation.
While neutral mutations, by definition, have no evolutionary effect at their inception, they may become significant either as a consequence of a change in the environment or through the allele's interaction with, or modification by, a subsequent mutation. Whenever that happens, however, natural selection still works by changing the occurrence of the allele from one generation to the next.
On reflection, my phrase "meaningful change must occur over that sort of period, or it is not going to happen at all" is inaccurate; to express what I was thinking, I would now write that "when evolution occurs, it is manifest from one generation to the next."
I see that you are aware that evolution has a tendency to occur in spikes, so it seems odd that you would write, in your initial post, "Considering the extraordinary amount of time it takes for evolution to do anything at all..." There is no requirement for there to be long periods of stasis between events.
This is not usually true and not typically how many species have evolved. Typically a long sequence of generations will exist with zero change, and then individual evolutionary events occur to create very rapid change in a very short period of time before stabilizing with long periods of no change again.
A lot of people here are expressing what they seem to think evolution is without apparently having ever actually studied it; that is my take-away anyway.
> But if that were the case, there would be plenty of such mutations still kicking around in the genome.
So does that mean the gene is less common in children than parents? If so, what does it matter that older people don't have the gene? Why does age factor into this at all?
This.
We want to live more (and more). But that's not the main point of life, as science (and most religions) say.
We are in our best form when we reproduce and give our best to our children (and family). So they can do the same in the future.
Today's society tries to sell the idea of small families (or no family at all ) and long lives as the best option. But maybe it's not the case.
Everything I've experienced and felt since youth indicates that my seed is unwanted by humanity, and it's clear suicide helps evolution by eliminating bad genes. I think about suicide constantly and have done so since youth. This is my brain telling me to help humanity by leaving. Hoping to complete that mission ASAP.
Anyway, it's too dangerous a topic for you to work things out without a bit of "peer review". So I strongly recommend to contact a counsellor.
People who don't survive aren't around anymore to discuss whether they are satisfied with their decision. Why would I waste my time talking to someone who intends to talk me out of something that isn't a debate to me? It's a personal decision.
Isn't it really about wanting to escape suffering?
Natural selection cannot.