Viewing a single comment thread. View all comments

iayork t1_ivd9jgu wrote

Genes associated with immunity are generally among the fastest-evolving genes, and this is because they are doing exactly what you ask about - reacting to changes in pathogens as they in turn react to changes in the host. This is one of the classic examples of the Red Queen’s Race (“running as fast as you can to stay in the same place”).

Just as one example: The poster children for rapid evolution are the genes of the major histocompatibility complex (MHC). These genes are critical for T cells to recognize pathogen antigens and they change very rapidly (see for example The rise and fall of great class I genes).

More generally:

> Adaptation is elevated in virus-interacting proteins across all functional categories, including both immune and non-immune functions. We conservatively estimate that viruses have driven close to 30% of all adaptive amino acid changes in the part of the human proteome conserved within mammals. Our results suggest that viruses are one of the most dominant drivers of evolutionary change across mammalian and human proteomes.

—Viruses are a dominant driver of protein adaptation in mammals

504

Kevin_Uxbridge t1_ivdeea4 wrote

Worth mentioning, this is also one of the stronger explanations for why sex exists at all. Reproducing sexually comes at a huge cost to your genome, as only half your genes will go into any particular offspring. A staggering cost evolutionarily, so why is it worth it? Because mixing your genome with others is a good way to keep pace with the many parasites trying to make a living off you. If it's either lose 50% or die, pay up.

312

Mugut t1_ivf7xry wrote

That "genome cost" only exists when considering the individual. But for a species, I see it more as a "genome remix" that expands the overall gene pool.

It also serves as a "gene wardrobe" where the species can host a particular gene as a recessive one, that might be harmful for the individual now but can save the species from extinction in the future.

I guess that what I'm getting at with all this rabble, is that succesful evolution caters to the whole species, with little regard for the individual.

54

Kevin_Uxbridge t1_ivf9ztk wrote

> That "genome cost" only exists when considering the individual.

A genome is the makeup of an individual, and can only be understood as such. Population genetics is the spread of genes but the mechanism, by necessity, acts on individuals with the genes. Your genes could be said to 'not care about you particularly' except as a vehicle for themselves, just as your genes in you don't give a crap about 'the species' except how it impacts your personal genome.

Not sure what you mean that evolution 'caters to the whole species'. Its effects can only be seen in these terms but the mechanism shapes the behavior of individuals to act on their own behalf. Sometimes this benefits the whole species, often it doesn't. That's just selection for you.

13

EmperorArthur t1_ivfe99l wrote

> A genome is the makeup of an individual, and can only be understood as such.

Nope. It's statistics that matter at the species level.

A recessive gene with madsive negative consequences will statistically become more and more rare, since at an individual level people who express it are more likely to not produce offspring.

However, if you then get a sudden change in environmental conditions which massively increases those people's survival chances or chances of increasing offspring, then the portion of the population with said gene is going to jump way up again.

8

fastspinecho t1_ivfdg5n wrote

> succesful evolution caters to the whole species, with little regard for the individual

Evolution is a phenomenon that acts on individuals, not species. It is manifested in the differences between an individual and its ancestors. "Species" is an artificial construct to help humans classify and describe individuals.

And evolution simply means "change", it is not "successful" or "unsuccessful" any more than gravity.

11

Roosevelt_M_Jones t1_ivfog3n wrote

.... individuals don't evolve. Individuals mutate, if the mutation is beneficial (or at least not highly detrimental) to thier survival they might pass it on, and eventually over enough gerations they might evolve into a new sprate species.

Your like half right in so many places, but have other things completely backwards.

https://www.pbs.org/wgbh/evolution/library/faq/cat01.html#:~:text=Individual%20organisms%20don't%20evolve,particular%20set%20of%20environmental%20conditions.

3

fastspinecho t1_ivfpz7b wrote

Evolution is much more than just the origin of species. It can be used to describe any individual with different traits than its ancestors, even within the same species.

It's true that an individual cannot evolve over the course of its lifespan. However, evolution fundamentally describes a relationship between multiple individuals (or if you prefer, a "population"), it is not necessarily acting on the entire species.

Elsewhere in the comments you can find a discussion of the sickle cell gene. This is an example of a relatively small population of individuals who evolved resistance to malaria (as well as a deleterious homozygous trait). They most certainly do not constitute a new species.

3

Roosevelt_M_Jones t1_ivfrgw3 wrote

"Evolution is change in the heritable characteristics of biological populations over successive generations."

https://en.m.wikipedia.org/wiki/Evolution

You're conflating mutation and Evolution. These are not the same thing. Just because a singular individuals is different from its ancestors dosen't meet the criteria of Evolution. It's a gradual and iterative process that takes generations and is very heavily intertwined with speciation.

1

fastspinecho t1_ivfs9rr wrote

Yes, it is related to speciation. But that does not mean it is acting to change an existing species. It is often acting at a much smaller scale.

In fact the definition you quoted doesn't even use the word species. It refers instead to generations, ie differences compared to one's ancestors.

−1

Roosevelt_M_Jones t1_ivgcqhm wrote

Look, just click on the link and read up on evolution, both that I have provided are reputable sources with the latter having a bunch of good citation of even more sources. Your clearly not understan some very fundamental parts of the theory of evolution or aren't clearly communicating what you mean, so you can either provide sources that back up what your saying or read what I've shared with you and further your understanding.

I mean the book in which the theory of evolution was first published is called "the origin of species" for Darwin's sake, you'd think that might be a good hint to the interconnection between the two concepts.

0

fastspinecho t1_ivgdije wrote

I read both sources, and I found nothing to support the contention that "successful evolution caters to the whole species with little regard for the individual".

Quite the opposite in fact. Evolution always begins at the level of individuals, and does not always affect the whole species.

> Sometimes, individuals inherit new characteristics that give them a survival and reproductive advantage in their local environments; these characteristics tend to increase in frequency in the population

3

Roosevelt_M_Jones t1_ivgelb8 wrote

Cool, not the point I was making and still not citing anything.

"The main difference between evolution and speciation is that evolution is the change in the heritable characteristics of a population over successive generations whereas speciation is the formation of a new, distinct species during the process of evolution."

https://pediaa.com/difference-between-evolution-and-speciation/

My point was that individuals do not evolve, period, that is not how evolution works. I will admit that speciation isn't the only way things evolve, and I was interlacing the concepts a bit, though this still only strengthens my main point the individuals do not evolve.

0

fastspinecho t1_ivgi3b0 wrote

> still not citing anything.

I cited the first paragraph of your linked article.

> The main difference between evolution and speciation

So, they are related concepts but not the same. Like I wrote earlier.

> individuals do not evolve

If you mean that a single individual cannot evolve over the course of its lifespan, then I'm glad you agree with what I literally wrote earlier.

If you mean individualS - plural - cannot evolve, then you are wrong. A group of individuals can evolve, even if the rest of the species does not. Which is why I wrote "evolution acts on individualS, not species". And why I didn't write "evolution acts on an individual".

0

Roosevelt_M_Jones t1_ivgx5ok wrote

Yes, you add that has I was writing my reply, hence me calling you out on that.

And your still not grasping that just because you make individual a plural that dosen't change that it takes gerations, that still be mutation. If you had read any of the links this wouldn't be an argument, but you just can't seem to grasp that evolution is a larger pheromon, not applicable to the minute scale of individuals. Yes, individuals do change, but for those changes to actually be evolution takes many gerations. You are just not able to understand the difference between mutation, adaptation, and evolution. You're clearly at least a little educated so I don't understand why you can't grasp this simple basic principle but at this point I'm just done trying explain it to you. You can plant your feet firmly on this common misconception.

Peace ✌️

0

fastspinecho t1_ivhyypy wrote

> evolution is a larger pheromon, not applicable to the minute scale of individuals. Yes, individuals do change, but for those changes to actually be evolution takes many gerations.

You mean like when I wrote that evolution "is manifested in the differences between an individual and its ancestors"? What do you suppose "ancestors" means?

All your arguments have been aimed at a straw man.

0

morderkaine t1_ivft4pw wrote

I would say that is not so - an individual doesn’t evolve, evolution is the change over time of a gene pool of a population of breading individuals. An individual human didn’t evolve the ability we have to sweat glands all over, but the slow change of offspring with better sweating abilities was selected for over a long time giving us the endurance advantage we have over most other mammals.

The change in an individual compared to parents would be more of a variance or mutation depending on what it is, it is only evolution when that change continues on in the population.

3

fastspinecho t1_ivfug13 wrote

My point is that not all evolutionary changes occur throughout a species, so it is wrong to say that evolution "caters to the whole species" with "no regard" for individuals.

In the comments, you can find a discussion of the evolution of the human sickle cell gene. It evolved in a relatively small group of individuals to provide those individuals protection against malaria. Those individuals are not a separate species, and if evolution were actually catering to the species as a whole then the gene would never have evolved.

1

__shamir__ t1_ivfomqp wrote

> successful evolution caters to the whole species, with little regard for the individual.

Actually, the opposite is true. See: "The Selfish Gene" or works along the same lines. Evolution occurs at the level of the individual alleles, even though actual survival/reproduction is at the level of the individual. Any species-wide evolutionary patterns observed are just a zoomed-out observed result of that individual evolution.

3

[deleted] t1_iveq8fx wrote

[removed]

14

MrZepost t1_ivevynm wrote

Minor inconvenience by comparison. More modern diseases like HIV not withstanding.

4

Mollusc_Memes t1_ivfnv3g wrote

Interesting. As a follow up question, is this fast evolution of immunity genes the reason why immunity to different diseases is one of the few significant differences between ethnic groups?

2

__shamir__ t1_ivfp4ij wrote

I think it's less about the speed of the evolution per se versus the different selection pressures. For example black people are far more likely than other races to have alleles for sickle cell anemia, because while two recessive copies produces sickle cell anemia, a single recessive allele produces only minor impairments in blood cell efficiency but massive improvements in malarial resistance.

(Note I prefer using the term race rather than ethnicity when talking about these thinks, because the concept of race correlates a bit better to genetics than ethnicity. Both are arbitrary social constructs, as everything in life is, but ethnicity has more to do with identity than it does raw physical similarity)

3