Wow, @Jpm , for a math slacker that was pretty good!
Say 7.5 million years since the last common ancestor, 25 years/generation in both species, that’s 300,000 generations.
Say 100 mutations/person/generation (mostly effectively neutral). Expect genetic drift to fix 100 mutations/generation. (That’s the standard assumption.) That’s 30 million mutations fixed by genetic drift per species.
3 billion base pairs in the genome (similar for both species) so that’s 1% in each species; 2% difference between species.
Please note, Richard Buggs is the expert, not me, so I’m accepting his figures.
The average is 88.9% so let’s round up to 90%. Neutral theory can account for about 1/5 of the genetic difference.
However since these are neutral mutation they probably have very little effect on the phenotypical differences between humans and chimps.
If we look at beneficial mutations ReMine has calculated that only 1670 beneficial mutations can have been fixed in 10 million years through natural selection. (ReMine’s paper was rejected by Nature not because of any error in his maths or conclusions but because the reviewers thought this was already well known.)
Perhaps some population geneticist can tell us how fixing of beneficial mutations would affect fixing of neutral ones. I assume some would ride on the coat-tails while others would be adversely affected.
I’m seeing major problems in this maths.
Royal blood lines are rarely if ever ‘pure’ and royal and noble males certainly ensured their genes ended up among the ‘commoners’. The creation of genealogies to support the ‘nobility’ or ‘royalty’ of one’s bloodline was well known. Also would you care to indicate what regions and groups have no genetic mixing (I’m not sure what you mean by ‘direct’ here). There are areas where there is less mixing (the caste system in India for instance in the last 1500 years) but never none.
I’m seeing major problems in your switching of units.
If a deletion–a single mutation–removes 50 bases of a 100-base sequence, what is the percent identity using
It’s good that you’re doing the math. It seems that your math makes the assumption that every mutation is a point mutation that results in a single, one base-pair difference in the genome.
This is not a valid assumption. Many single-event mutations result in differences of hundreds or thousands of base-pairs. Here are some examples:
- Copy number variation
- Gene duplication
Grace and peace,
That would be a total of 60 million mutations. The actual number is around 40 million mutations that separate the human and chimp genomes:
If we are talking about the number of fixed mutations then you have to count a single 500 base pair indel the same as you would a 1 base substitution. Don’t get your units mixed up.
From what I have read, Buggs has confused lack of orthology between the sequenced genomes and lack of orthology in the actual genomes. There are gaps in the sequenced DNA for both humans and chimps, and there are also chunks of DNA that are kept out of alignments because no one knows where that DNA fits into the larger genome.
Added in edit:
There was a thread a while back where Buggs himself discusses these numbers with other posters at BioLogos:
That is correct. Neutral mutations can can become fixed with the rest of the allele when a beneficial mutation occurs.
Even your own math puts the number of mutations at 60 million mutations which is 20 million more than actually exists, according to the chimp genome paper.
Glad to see someone else has noted this. I first learned that when I read this paper.
An average of 30 mutations per generation and fixing 100 how does that lead to progression it doesent. Most theoretical ranges for mutation rates anticipate 30 to 50 mutations per generation or in actuality depending on conditions .1 to 1 per year so with quicker development of progeny the effective rate decreases because of healthier cells and less probability of negative exposure. So 3 million years with only 1 in 4 shot of giving most mutations to offspring due to multiple chromosones and mutations not being present throughout all of your chromosones etc your tree falls apart. Also a population of a million people is an unreasonable hypothosis throughout almost the entire 3 million year time frame logical estimates would be drastically smaller and intermixing unlikely. So 300000 base pare mutations vs 40000000, genetic material does not and cannot conglomerate in the method you have proposed bc none of them would have the same mutation on both chromosones or from both parents. So likelyhood of passing on mutation to second generation at best 1 in 4 to 1 in 8 depending on the type of mutation. And that progresses throughout future generations as well which is like red hair passing down in background it can happen but is unlikely. None of youre calculations acxount for this. So at most on average you end up with same number of total mutations in a lineage equal to the mutations per year in a single lineage, they do not spread throughout a population as proposed above and are not typically selected for unless drastically benificial. The total number of mutations in a population gives it diversity yes but cannot be combined to form total genetic change. It cannot work that way. If it did then we would evolve that same amount now with every generation. In actuality a larger population eventually leads to stagnation and a virtual impossibility of genetic progression in mathamatical terms.
That’s 50 mutations PER PERSON per generation. I think you forgot to take that into account.
You are forgetting that each offspring also has 50 new mutations all their own.
“For a diploid population of size N and neutral mutation rate u, the initial frequency of a novel mutation is simply 1/(2N), and the number of new mutations per generation is 2Nu . Since the fixation rate is the rate of novel neutral mutation multiplied by their probability of fixation, the overall fixation rate is 2Nu x (1/2Nu) = u. Thus, the rate of fixation for a mutation not subject to selection is simply the rate of introduction of such mutations.”
(Note: @pevaquark did some light editing aiming to make a few paragraphs to see where one idea stops and the next one starts)
In actuality there is not neccessarrily 50 mutations per generation, in fact its a yearly progression of depending on circukstances .1 to 1 bp per year so 25 year old having offspring would be between 2.5 and 25 bp mutations however only approximately 1 in 2 chance of those being passed at best however correction lowers that to 1 in 4 , remember chromosones are in sets of 2 and you only pass one so mutation on non paased sequence is meaningless so on average less than half of mutations are passed to offspring due to correction. Secondarily even the number of 50 mutations already takes in to account both parents and average age. So 50 per generation witha persistance rate of 50 percent into the following generation which again perpetuatis itself. Incomplete math is a pet peve of mine. 300000 generations and 50 per would yield only 15 million events in a lineage remember both parents are considered and the larger the population the less likely a full adoption of genomic change is to take place. And if we are talking distinct species a bottleneck event has to take place to seperate it. Now with the persistance generation to generation you can figure at most 7.5 of those 15 million to make it through the lineage if its a small population and vastly less if its a larger population simce more unaltered pairs exist to fix the error expecially with non advantageous pairings. This does not yield under any circumstance a 40 million base pair change over 7.5 million years. Alot of our genomic change expectations are based on currently observed mutation rates which are in a much more mutagenic environment with many more dietary variables and airborne toxins than would have been present at the supposid time of "evolution’ people who eat healthier less processed food and live in cleaner environments average closer to the .1 bp per year mark remember its a continuum not a constant. Also succesfull mutations on active sequences are almost always fatal and there are many points of transition between the species that would not have been servivable.
Also there is evedince lf more human like footprints pre dating some of th supposid common ancestors. Most of the radioactive dating methods have lots of evidence proving them unreliable. Radiometric dating for pompei as an example puts it at several million years old. And mount saint helens as well the valley created by it dates at over 2 million years. We have alot of chronology problems we need to fix obviously with those 2 there is an order and not only age issue since most tests show the more recent event to pre date the older one. This is a problem with many of the radiometric tests even tests of different parts of the same strata come up with different ages drastically different even we know they were formed together.
More of the differences are in active dna sequences and when you rate the probability of change in a certain dna sequence and work it out there is an even more definitive andswer as to simple random genetic mutation not being possible in the time frame. A speckfic utterance of the so called common ancestor equal distant from both prevailing species has not been found only proposed due to a mathmatical calculation based on the differences between the species. It for all the instances i have directly looked into has had many major errors in the calculation methodologies not sound genetically speaking. Propogation of genomic change throughout generations cannot be boiled down as simply as many mathmaticians have pre supposed. I like how einstein put it of all that is true of mathmatics nothing is true of reality.
Would you be interested in learning more about how radiometric dating is done? Like what kinds of rocks can be dated, how can your results be cross checked, how can any assumptions be tested and eliminated, what is the underlying Physics and how do we even know the half-life of various radiometric elements? It is an extremely reliable technique with limitations- you appear to be reporting some of the intentionally misleading misapplications of the method- not how geologists actually use the technique to date anything.
Looks good. Matthew Bates wrote a book called “Salvation By Allegiance Alone,” which talks about “pistis” a lot, as well; Scot McKnight wrote an endorsement. It really does broaden my understanding of “faith.”
Current estimates for the human mutation rate range roughly from 1.0 to 1.7 x 10^-8 mutations per bp per generation. Note that these estimates are almost always for the single-base substitution rate; the total mutation rate, including insertions and deletions, will be something like 20% higher. That translates into 30 to 50 single-base substitutions per genome copy per generation. If human-chimpanzee speciation occurred 7 million years ago, from an ancestral population size of 50,000, and if mean generation time was 25 years, then a human and a chimpanzee genome should be separated by ~380,000 generations (280,000 generations back to the speciation time, and another 100,000 generations for chromosomes within the ancestral population to coalesce). With the range of mutation rate estimates from above, that means we should expect to see between 23 million and 39 million single-base substitutions when comparing human and chimpanzee genomes. We actually observe 35 million. Where’s the problem, exactly?
No, there need be no bottleneck in speciation.
I don’t know what you’re trying to say here, but it doesn’t seem to have anything to do with the calculation you’re trying to do. Population size is irrelevant if you’re calculating the difference between two genomes – you’re just counting how many mutations have occurred in the two lineages since the two copies were identical.
I know of no evidence that this is true. If anything, modern chemical exposure might have increased the mutation rate, not decreased it.
In recent studies of actual generations of 78 family lines in iceland showed an average of 60 mutations accumulated per generation for 30 year average generations so about 2 per year which should remain fairly constant no matter the genration timespan, it could be argued that in the past the rates would have been lower due to less processed food and less poluted environment but we can ignore that for now. This over 7.5 million years would only lead to 15 million base pair changes, and the closest "related species is 40 million bp 3 million years apart, so even if you double up the spread patern it only yields 12 million changes and there is not enough time so either of these being common ancestors os completely disproven because there is only 1/3 of the time that would be necessarry even under perfect conditions. Secondarily from all that we have observed with the frequency of benificial mutations to have so many benificial mutations accumulate over such a period of time is not mathmatically sound.
Additionaly 40% of these were fixed within three generations by genetic controls in replication and none of them observed were possitive and less than 10 percent did anything.
@Clint_Goolsby please provide sources to your claims.
For your particular claim regarding Icelanders, here is the source:
Okay. Note that this again is for single-base substitutions only.
15 million single-base substitutions in the human lineage. Add another 15 million in the chimpanzee lineage. That’s 30 million, compared to the 35 million actually observed. Now add some extra time because the ancestral population was probably large, and the observed number looks just about spot on.
Note chimp commonancestor supposidly 3 million years ago and the mutation rate of 2 per year on average includes all mutations, single bp is about 1 per year, between ape is said to be 7.5 but thats over 80 mill bp, now these common ancestors that supposidly exist have not been found. They are postulated by reverse engineering mutations taking an average and putting the point at where equa distant with similar mutation time scale range. Now only 50% of mutatioms get passed in lineage to second generation remember we dont pass all our chromosones so the total divergence between species of 15 million bp over 7.5 million years and 6 million bp over 3 million years is the most likely. Due to the scale of divergence i believe the common ancestor computation to be flawed if there is one it would have to be farther back. Like 20 million years between us and chimp and 40 to 60 for ape, now the presence of other species and cross breeding proves not distinct species, in other words neanderthals if capable of breeding with us are not a different species, a different lineage maybe but not species remember genetic differences does not make 2 things different species they are only different if they cannot yield multiple generations of viable offspring. Thus the recent discovery that we have over 2 percent neanderthal intact genome proves they were not a seperate species and until you can reverse engineer a common ancestor for ape and chimp with neanderthal as well their so called common ancestor is false since we were obviously the same “species” as neanderthal just mostly a different lineage with only some of theirs being maintained over the generations. All mutations fade in a similar manner at one point there had to have been half neanderthal people as well, some sort of bottleneck just weeded out most of that lineage. The common ancestor with anything other than neanderthal must have taken place before neanderthal because they were not a distinct species.
I posted the calculation of the expected number of mutations earlier today. If you have any questions about what I posted, please ask, and please make it specific. Simply repeating yourself is not accomplishing anything.
Just a moment ago you said it was 7.5 MYA:
What made you lop 4.5 million years off the estimate? Would you care to provide some documentation for the dramatically lower estimate? Everything I have read is in agreement with what a leading expert in the field stated in this very thread:
Unless you can provide some documentation for your assumptions, I can’t verify your argument. And if I can’t verify it, I can’t trust it.
I suggest Richard Buggs calculations from 2017/18 are more up to date than those done in 2005, that is probably >10% difference. I’m not sure how much “approximately thirty-five million single-nucleotide changes, five million insertion/deletion events” would add up to but since most indels are quite small, <10bp, I doubt the total will reach that. If you want to argue that neutral theory could explain 10% difference (or more) you should provide references where size, frequency, and rate of being fixed is fully taken into account for both neutral and selectable mutations.
None of that explains orphan genes or the differences between humans and chimps. Neutral mutations are by definition, well, neutral; they have no selectable affect.