Origin of Cytochrome C

I’m still not seeing any numbers.

Looking around, there are about 7.5 x 10^18 (i.e. 7.5E18) grains of sands on the Earth. reference

Now, let’s look at cytochrome c which is just one protein. It is estimated that there are 1E93 functional sequences for cytochrome c:

That’s just one protein. For just one protein there are more possible functional sequences than there are atoms in the universe. THAT’S JUST ONE PROTEIN. It is entirely possible that there are very different proteins that can serve that same function. We haven’t even arrived at the number of possible functions. I think your estimates are way, way low.


ok. but that is the same function. we are talking about different functions. the chance to get the same function is much higher than the chance to get a different function since if there are about 10^90 possible combinations to produce a single funtion it means that there is at max 10^40 different functions among that space (because there are 10^130 possible combinations for 100 amino acids). so as you can see the ratio for different function is much lower than for identical one.

The above fails immediately if there are proteins that perform multiple functions.

ok. so lets go with my first example: what make you think that there are more functional proteins than the number of sand grains on earth?

the second problem is with convergent evolution. if we will use the number from talkorigin (10^40) for a specific function then it means that to get the same function again by convergent evolution is extremely unlikely. so we need to expain it too.

1 Like

Yockey’s estinmate for cytochrome C is a good start.

You’re underestimating by more than 75 orders of magnitude.

That number isn’t from talk.origin, it’s yours. So the only necessary explanation is that your estimates of probability aren’t reliable.

1 Like

where? i never said that there is a single sequence that can function as cytochrome c.

yes it is. here:

" Importantly, Hubert Yockey has done a careful study in which he calculated that there are a minimum of 2.3 x 1093 possible functional cytochrome c protein sequences, based on these genetic mutational analyses (Hampsey et al . 1986; [Hampsey et al . 1988]"

Context restored and emphasis added:

The number in the talk,origins article is 2.3*10^93. Nowhere does it mention 10^40.

You are being untruthful, and no further response is necessary.

1 Like

simple calculation: if there are about 10^93 different sequences that can perform cytochrome c function (out of 10^130 possible combinations for 100 amino acids), it means that one in every 10^37 different sequences will perform cytochrome c function.

Has cytochrome c evolved de novo multiple times independently? If not, we don’t need to explain that. Also, there are functional cytochrome c’s known as short as 70 residues in length last I checked.

1 Like

not specifically the cytochrome c but many other complex structures. i gave it as an example.

interesting but i dont think that it will change the picture so much. as talkgorigin put it: " Furthermore, extensive genetic analysis of cytochrome c has demonstrated that the majority of the protein sequence is unnecessary for its function in vivo (Hampsey et al . 1986; [Hampsey et al . 1988]. Only about a third of the 100 amino acids in cytochrome c are necessary to specify its function."

so the core of the protein may be the same in both proteins. and even if not we are still talking about 70 aa compare with 100. so i dont think that it will change so much. remember that a tipical protein is much longer than 100 aa.

Interestingly, the increase in probability of generating by chance a 70aa protein rather than a 100aa protein (10^39) of which scd says “i dont think that it will change the chance so much” - is comparatively greater than the improbability he gives for re-evolving cytochrome C (10^37), which he says is “extremely unlikely”.

So not only is he misrepresenting his sources, he’s also mischaracterising the results that he would get if he could do the calculations.

And he’s using cytochrome C as an example of something he knows it’s not an example of.


But you can’t just extrapolate like that from one function to another. Some functional sequences are extremely abundant in sequence space, some are much more rare. In fact on this very website in another thread we have Bill Cole say:
“The evolutionists smoke and mirrors game is to show a single protein and say that is representative of all proteins.”

We noted the irony there, I will do so again here.

The total sequence space for a protein 70 amino acids in length is approximately 10^91. That means there are more functional cytochrome c sequences(of any size), than there are possible sequences of L=70.

So of course it matters. But obviously not every sequence in that L=70 space will then be a cytochrome c, that doesn’t follow. But it does highlight an issue with looking exclusively at sequence space of a given length. Which I will try to highlight below. It also highlights an issue with these estimates for the total number of functional sequences, as they are based on extrapolations from known functional proteins.

So the core of the protein may be the same in both proteins. and even if not we are still talking about 70 aa compare with 100. so i dont think that it will change the chance so much. remember that a tipical protein is much longer than 100 aa.

This is where we run into an issue with looking exclusively at proteins of some specific length, like 100 amino acids.

If there are 10^93 functional cytochrome cs, and we restrict sequence space to sequences of (say) length 80, then approximately one in every ten million sequences could be a functional cytochrome c.

Sequence space for L=100 is approximately 10^130. 10^130/10^93 = 10^37
So, the odds of finding a functional cytochrome c just by arbitrarily picking a 100 aa sequence is approximately 1 in 10^37. That’s the number you came up with above, for 100 aa space.

But what happens for 80 aa space?
Sequence space for L=80 is approximately 10^104. 10^104/10^93 = 10^7.

So moving from 100 amino acid to 80 amino acid sequence space potentially increases the odds of finding a functional cytochrome c by thirty orders of magnitude.

Moving down to 70 amino acid sequence space we get total sequence space of approximately 10^91. That’s FEWER sequences than there are total cytochrome cs. If we just looked exclusively at 70 aa space we would have to paradoxically conclude all sequences in 70 aa space are functional cytochrome cs. That obivously can’t be the case.

Now, the problem here is that we don’t know how functional cytochromes are distributed in sequences space in relation to size. It could be that most of the functional cytochrome cs are found in the 80-90 range, or the 90-100 range, or 100-120, or the 60-70 range. We simply don’t know, so you simply cannot pick a length, calculate the total size of sequence space, and then divide that space by the estimated total number of functional cytochromes to get a probability of obtaining one. It is logically not possible when you don’t know the relationship between size and density of function.

1 Like

This does not work until you know the functional space of the 80 or 70 AA cytochrome C. You cannot assume it is the same as the function may be concentrated at a specific AA group. The shorter protein may have just eliminated neutral sites. Also there is evidence that cytochrome C has developmental function in mammals along with electron transport.

I know, read further in my post. I explain exactly that problem.


Sure looks like Bill just admitted he has no idea what the functional space of any cytochrome C is and therefore his calculated FI value is worthless. :slightly_smiling_face:


Cytochrome C is not a highly preserved protein.

Which doesn’t change the fact you don’t know the functional space for any protein. That makes all your FI calculations worthless. :slightly_smiling_face:

1 Like

This is an even worse admission since you are admitting that FI can’t be calculated for newly emergent proteins. This also means that FI is simply a measure of how long ago a protein emerged.

1 Like

74 posts were merged into an existing topic: Origin of Proteins

indeed. so? remember that we only need few of the rare examples to challenge unguided process. and there are probably much more than just few rare examples in nature.

problematic assumption. remember that about third of the cytochrome c protein is crucial for its function. so only about 30 aa are needed theoretically. thus the chance is 20^33, very close to 10^37 (i guess that Yockey calculation might base on that). it means that the chance to get even a shorter cytochrome might be similar. alternative explanation is that a third of the shorter version of cytochrome c is needed. in that case we are talking about 23 aa, or 20^23. i think that this number is more realistic.

do you agree that as far as we make the space larger, the chance to get a specific function is getting smaller too?