# Does neutral evolution explain the genetic differences between humans and chimpanzees

**URL:** <https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271>\
**Category:** Conversation\
**Tags:** Science\
**Created:** [February 27, 2021, 2:24pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271 "2021-02-27T14:24:45Z")\
**Posts on this page:** 20\
**Page:** 1

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 2:24pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/1 "2021-02-27T14:24:45Z")

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I watched the following video where Dr. Swamidass tries to explain the genetic differences between humans and chimpanzees using the concept of Distance = Rate x Time, neutral evolution.

[![](https://us1.discourse-cdn.com/flex016/uploads/peacefulscience/original/2X/3/3e286cc0d681cbd7f757b0fcd97f5a0d0f7b7d31.jpeg "Dr. Joshua Swamidass Explains Why He Changed His Mind on Evolution") ](https://www.youtube.com/watch?v=cQEinFT6gSY)

(41min).

There is a flaw in this argument. What that flaw concern is the meaning of beneficial, neutral, and detrimental mutations. Those adjectives for the word mutation concern reproductive fitness. A beneficial mutation increases reproductive fitness, a neutral mutation does not change reproductive fitness, and a detrimental mutation reduces reproductive fitness.

At this time, there are about 7.1 billion humans on earth.

> **[How Many People Have Ever Lived on Earth?](https://www.prb.org/articles/how-many-people-have-ever-lived-on-earth/)**
>
> The global population milestone of 8 billion people represents nearly 7% of the total number of people who have ever lived on Earth.

At this time, there are about 300,000 common chimpanzees on earth.

> **[How Many Types Of Chimpanzees Are There?](https://www.worldatlas.com/articles/how-many-types-of-chimpanzees-are-there.html)**
>
> Chimpanzees are extant great apes that are one of the two species of the genus Pan, the other being the bonobo.

The chimpanzee population size is about 0.0042% of the size of the human population size. Therefore, humans have vastly greater reproductive fitness than chimpanzees. If you want to claim that humans and chimpanzees evolved from a common ancestor, humans must have gotten some beneficial mutations along the way to give that vastly greater reproductive fitness. How exactly are these adaptive mutations accumulated to give this vastly greater reproductive fitness that humans demonstrate over chimpanzees?

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [February 27, 2021, 3:50pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/2 "2021-02-27T15:50:20Z")

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> [@kleinman](#):
>
> If you want to claim that humans and chimpanzees evolved from a common ancestor, humans must have gotten some beneficial mutations along the way to give that vastly greater reproductive fitness.

What do you mean “if you want to claim”? How can you possibly ignore all the evidence that this is true? And of course humans have fixed some beneficial mutations. How many do you think there have been? Certainly it’s not any significant fraction of the approximately 20 million fixed changes in the human lineage, or would you disagree? If these beneficial mutations are relatively few, how can that affect @swamidass’s argument?

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 4:17pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/3 "2021-02-27T16:17:08Z")

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How many beneficial mutations does it take to get a more than four-order of magnitude increase in reproductive fitness (300,000 vs \>7billion)? If you can, tell us how beneficial mutations accumulate on a lineage. If you have trouble with that math, you can find it here:  
[The Kishony Mega-Plate Experiment, a Markov Process](https://www.researchgate.net/publication/344353730_The_Kishony_Mega-Plate_Experiment_a_Markov_Process_Running_Title_The_Kishony_Mega-Plate_Experiment)

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [February 27, 2021, 4:49pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/4 "2021-02-27T16:49:55Z")

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Nice to see you again @kleinmar. I think you were last here two years ago ([Kleinman: Four Questions About Evolution](https://discourse.peacefulscience.org/t/kleinman-four-questions-about-evolution/4847)).

You are a legitimate scientist who has published in adjacent areas, though you do hold a minority position. Out of respect for you, and to keep this conversation on track, [@moderators](https://discourse.peacefulscience.org/groups/moderators) will limit this thread to qualified scientists prepared to engage with you with respect and substance.

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**Author:** ![CrisprCAS9](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/crisprcas9/32/9145_2.png) [@CrisprCAS9](https://discourse.peacefulscience.org/u/CrisprCAS9)\
**Post date:** [February 27, 2021, 4:50pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/5 "2021-02-27T16:50:22Z")

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> [@kleinman](#):
>
> How many beneficial mutations does it take to get a more than four-order of magnitude increase in reproductive fitness

At least one. Possibly several.

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**Author:** ![Timothy\_Horton](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/timothy_horton/32/9410_2.png) [@Timothy\_Horton](https://discourse.peacefulscience.org/u/Timothy_Horton)\
**Post date:** [February 27, 2021, 4:50pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/6 "2021-02-27T16:50:29Z")

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The huge increase in human population didn’t all come directly from beneficial mutations. There were a few beneficial mutations which increased our intelligence and thereby our tool making capability. This extra capability allows humans to be the first species to manipulate their environment on the scale we do, a manipulation which led to the explosion in population.

Fixed typo

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [February 27, 2021, 4:50pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/7 "2021-02-27T16:50:33Z")

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> [@kleinman](#):
>
> How many beneficial mutations does it take to get a more than four-order of magnitude increase in reproductive fitness (300,000 vs \>7billion)?

You answer a question with a question? Also, you would appear to misunderstand even the concept of absolute fitness. Wouldn’t that be the per-generation increase rather than the total increase over millions of years?

> [@kleinman](#):
>
> The Kishony Mega-Plate Experiment, a Markov Process

Have you even submitted that anywhere?

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**Author:** ![swamidass](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/swamidass/32/3_2.png) [@swamidass](https://discourse.peacefulscience.org/u/swamidass)\
**Post date:** [February 27, 2021, 4:52pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/8 "2021-02-27T16:52:48Z")

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> [@kleinman](#):
>
> How many beneficial mutations does it take to get a more than four-order of magnitude increase in reproductive fitness (300,000 vs \>7billion)?

Population size is not correlated with fitness. Instead, fitness is relative to environment and other members of the population. It is not, therefore, a fixed quantity.

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:07pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/9 "2021-02-27T17:07:57Z")

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> [@John\_Harshman](#):
>
> > [@kleinman](#):
> >
> > How many beneficial mutations does it take to get a more than four-order of magnitude increase in reproductive fitness (300,000 vs \>7billion)?
> 
> You answer a question with a question? Also, you would appear to misunderstand even the concept of absolute fitness. Wouldn’t that be the per-generation increase rather than the total increase over millions of years?
> 
> > [@kleinman](#):
> >
> > The Kishony Mega-Plate Experiment, a Markov Process
> 
> Have you even submitted that anywhere?

Define fitness any way you want but clearly, humans have vastly out-replicated chimpanzees.

And yes, the paper is in peer-review at this time. If you read this paper, do you understand the problem with the Jukes-Cantor (and derivative) model(s) of DNA evolution?

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:08pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/10 "2021-02-27T17:08:03Z")

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> [@Timothy\_Horton](#):
>
> The huge increase in human population didn’t all come directly from beneficial mutations. There were a few beneficial mutations which which increased our intelligence and thereby our tool making capability. This extra capability allows humans to be the first species to manipulate their environment on the scale we do, a manipulation which led to the explosion in population.

So, how many replications does it take for a beneficial mutation to occur, and how does a lineage accumulate a set of beneficial mutations?

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [February 27, 2021, 5:08pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/11 "2021-02-27T17:08:08Z")

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> [@swamidass](#):
>
> Population size is not correlated with fitness.

Kleinman refers to absolute fitness, not relative fitness, though he uses even that term incorrectly.

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:08pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/12 "2021-02-27T17:08:17Z")

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> [@CrisprCAS9](#):
>
> > [@kleinman](#):
> >
> > How many beneficial mutations does it take to get a more than four-order of magnitude increase in reproductive fitness
> 
> At least one. Possibly several.

So, how many replications does it take for a beneficial mutation to occur?

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:08pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/13 "2021-02-27T17:08:36Z")

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> [@swamidass](#):
>
> You are a legitimate scientist who has published in adjacent areas, though you do hold a minority position. Out of respect for you, and to keep this conversation on track, [@moderators](https://discourse.peacefulscience.org/groups/moderators) will limit this thread to qualified scientists prepared to engage with you with respect and substance.

I appreciate that. And I don’t mind holding the minority view.

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [February 27, 2021, 5:10pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/14 "2021-02-27T17:10:54Z")

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> [@kleinman](#):
>
> And yes, the paper is in peer-review at this time.

Where?

> [@kleinman](#):
>
> If you read this paper, do you understand the problem with the Jukes-Cantor (and derivative) model(s) of DNA evolution?

I understand that you are sorely mistaken. If you have submitted it to a legitimate, on-topic journal, the reviewers will doubtless inform you.

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**Author:** ![CrisprCAS9](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/crisprcas9/32/9145_2.png) [@CrisprCAS9](https://discourse.peacefulscience.org/u/CrisprCAS9)\
**Post date:** [February 27, 2021, 5:11pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/15 "2021-02-27T17:11:00Z")

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> [@kleinman](#):
>
> So, how many replications does it take for a beneficial mutation to occur?

At least one. Possibly several. Obviously.

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<div class="post-metadata">

**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:21pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/16 "2021-02-27T17:21:23Z")

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> [@swamidass](#):
>
> Population size is not correlated with fitness. Instead, fitness is relative to environment and other members of the population. It is not, therefore, a fixed quantity.

Then, why do you assume you can calculate evolutionary distance = rate x time? Clearly, humans could and do live in the same environment that chimpanzees do and achieve far larger populations. In fact, one of the reason that chimpanzees might go extinct is human encroachment on the chimpanzee environment. That is classic Darwinian competition. So, how many beneficial mutations do you think it required for humans to get in this evolutionary position?

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**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:21pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/17 "2021-02-27T17:21:32Z")

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> [@John\_Harshman](#):
>
> I understand that you are sorely mistaken. If you have submitted it to a legitimate, on-topic journal, the reviewers will doubtless inform you.

We’ll see. Why don’t you see if you can find any error in that paper?

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**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [February 27, 2021, 5:30pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/18 "2021-02-27T17:30:53Z")

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> [@kleinman](#):
>
> We’ll see. Why don’t you see if you can find any error in that paper?

Have you in fact submitted it to a legitimate, on-topic journal? What journal?

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<div class="post-metadata">

**Author:** ![John\_Harshman](https://sea2.discourse-cdn.com/flex016/user_avatar/discourse.peacefulscience.org/john_harshman/32/1121_2.png) [@John\_Harshman](https://discourse.peacefulscience.org/u/John_Harshman)\
**Post date:** [February 27, 2021, 5:31pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/19 "2021-02-27T17:31:10Z")

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> [@kleinman](#):
>
> Then, why do you assume you can calculate evolutionary distance = rate x time?

Because that’s how neutral evolution works, and the overwhelming majority of the mutations separating humans and chimps are evolving neutrally. Have you yet accepted that neutral evolution exists?

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<div class="post-metadata">

**Author:** ![kleinman](https://avatars.discourse-cdn.com/v4/letter/k/b3f665/32.png) [@kleinman](https://discourse.peacefulscience.org/u/kleinman)\
**Post date:** [February 27, 2021, 5:31pm UTC](https://discourse.peacefulscience.org/t/does-neutral-evolution-explain-the-genetic-differences-between-humans-and-chimpanzees/13271/20 "2021-02-27T17:31:28Z")

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> [@CrisprCAS9](#):
>
> > [@kleinman](#):
> >
> > So, how many replications does it take for a beneficial mutation to occur?
> 
> At least one. Possibly several. Obviously.

So, how many replications of a variant does it take to have a reasonable probability of a beneficial mutation occurring? If you have difficulty doing that math, I can show you how to do it. If you want to see an evolutionary experiment that demonstrates this process, watch this video:

[![](https://us1.discourse-cdn.com/flex016/uploads/peacefulscience/original/2X/2/26e14c196be56e33e05efc768c800290d13592fe.jpeg "EXTRA MINUTES - SUPERBBUGS (Harvard Experiment explained)") ](https://www.youtube.com/watch?v=Irnc6w_Gsas&t=2s)

Try to explain how this evolutionary process is working.

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