Evolution of KRAB Zinc Finger Proteins vs. the Law of Large Numbers
There are patterns in biology that violate the law of large numbers, and thus suggests Intelligent Design or at the very least statistical miracles. The pattern involves KRAB-ZnF proteins that have multiple zinc finger domains side by side that are inexact copies of each other and would require a scenario of co-evolution of their DNA binding partners with every additional zinc-finger insertion — a scenario indistinguishable from a miracle.
The role of a zinc finger can be something like a clamp or a lock. Each zinc finger in a KRAB-ZnF protein is fine-tuned to connect with a DNA much like a lock (the zinc finger) can receive a key (like DNA). Here is a depiction of a KRAB-ZnF protein with 4 zinc fingers as part of a large chromatin modifying complex. The four zinc fingers are marked “ZN” and connect to DNA:
The evolutionary explanation of side-by-side repeated patterns of zinc fingers such as in KRAB-ZnF proteins shows a severe lack of critical thinking by evolutionary biologists who pretend “phylogenetic methods” are adequate explanations of mechanical feasibility of common descent.
To illustrate the problem, consider the KRAB-ZnF protein known as ZNF136. For reference, this is the amino acid sequence of ZNF136:
This is an amino acid fragment contained within the ZNF136 protein
This short sequence is called a zinc finger domain which in 3D looks like this:
Wiki gives a description of the function of zinc fingers in proteins that have them:
A zinc finger domain requires two “C” amino acids and two “H” amino acids placed in the right positions. It requires a few other things too…
There are 13 zinc fingers in the ZNF136 protein and these are their sequences:
For completeness, there is a degenerate zinc finger in ZNF136 with the sequence “YGEKPDTRNQCWKPFSSHHSFRTHEIIH”
Why are the Zinc Fingers so different in sequence (except for the conserved amino acids)? To target a section of DNA, the zinc finger must be tuned to target it. Think of the zinc finger like a lock and DNA as a key that fits into the lock. In fact, for both the study of biology and medical applications, humans have a desire to make their own zinc fingers — like lock smiths. To bind a large segments of DNA, side-by-side zinc-fingers have to be tuned to their respective side-by-side DNA partners such as illustrated here:
By the way, there is a website that helps researchers construct the right amino acid sequence to make a zinc finger for a particular DNA target:
Now, to visualize the critical/conserved amino acids, see the protein sequence here with highlights on “C” and “H” amino acids.
Note one of the lines is not exactly like the other lines in that it is missing a “C”. This is the degenerate zinc finger mentioned above. So there is 1 degenerate zinc finger and 13 functional ones.
From this diagram it is apparent that the regular appearance of “C” and “H” is a violation of the law of large numbers, hence this pattern is not due to random point mutation alone. To “solve” this problem, Darwinist explain the pattern through segment duplication followed by some point mutation and natural selection, but this is not mechanically feasible either!
To understand why, let the reader first ponder the alignment I made of the Zinc Fingers in the ZNF136 protein using MEGA 6.0/MUSCLE software:
Then let the reader, consider the distance matrix generated by MEGA 6.0 which measures the number of nucleotide and percent differences between the zinc fingers.
(All of the above results are reproducible, so I leave it to interested parties wanting to confirm the results to do so.)
For the duplication to work, at a bare minimum the right 84 nucleotide segment must be chosen, and then perfectly positioned for insertion so as not to break a pre-existing zinc finger. But supposing the duplication succeeds, why are the zinc finger’s conserved features involving “C” and “H” and other amino acids preserved and not eventually erased by point mutation given we obviously see the zinc fingers are different from each other. To preserve the “C” and “H” and other necessary amino acids in a zinc finger, the new zinc finger needs to be under selection. But in that case one is simply concocting a “just so” story for those newly minted zinc fingers without any respect for the difficulty of such a “just so” story being probable — and it is not probable!
To understand the problem of such a “just so” story, recall zinc fingers bind to DNA regions. Btw, this includes DNA regions such as ERVs! And ERVs are indicated to participate in the Stem Cell Pluripotency regulatory network:
Further, the KRAB-ZnF protein is part of an incredibly complex machine that does chromatin modification (as shown above) by often attaching to ERV targets. But this would require that ERVs (or whatever DNA target) needs to co-evolve with the KRAB-ZnFs that attach to them!
Do these researchers even consider the fact such evolution would have to be instantaneous otherwise it would degrade function and not let the genome have the opportunity to adapt to the new accidental copy of the zinc finger because the duplication would immediately be selected against!
The above KRAB-ZnF complex is like a read/write head acting on Chromatin. Chromatin itself is an amazing mind-boggling design akin to computer ROM and RAM in one.
Again, the difficulty of evolution via random insertion/duplication mutations followed by point mutations is that such events would disrupt the binding of an already operational set of zinc fingers. For example, suppose we have an array of 10 zinc fingers side-by-side that collectively bind to a target DNA. Suppose one zinc-finger is duplicated and the number of zinc fingers is increased from 10 to 11. Oh well, the binding ability is broken or at best compromised, much like adding a single letter to a pre-existing password!
In sum, there is a violation of the law of large numbers in KRAB-ZnF proteins which is not explained by random mutation, nor random segment duplication followed by some point mutation and fixed by natural selection. Some other mechanism for the emergence of such proteins is indicated and would likely be indistinguishable from a miracle. Given the importance of such zinc finger proteins in the control of ERVs which are important in the stem cell pluripotency regulatory circuits, the origin of KRAB-ZnFs is even more miraculous.