(For part 1 in the series, click here)
If macroevolution occurs, it must do so at the biochemical level. Additional genetic information is needed to build the new proteins and biological systems required for large-scale changes. Where does the new biological information come from? Mutations? No. Point mutations such as inserting, inverting, or substituting nucleotides in existing genes cannot increase the information content of DNA even if they occur in protein-coding regions, and even if the mutations are beneficial to the organism. At best they can only replace existing information/function with different information/function, so that the overall information content is merely preserved. For macroevolution to occur a net increase of information is required, not just a change in existing information.
The origination of new genetic information requires new proteins, which requires hundreds of additional nucleotides arranged in a highly specified order. How likely is it that chance processes can get the job done? Next to none. The chances of producing a functional amino acid sequence of a mere 150 nucleotide bases (which would sequence one of the smallest proteins) is 1:10164. To put this number in perspective, consider that there have only been 10139 events in the entire universe since the Big Bang. So even if every event in the history of the universe was devoted to building a single functional protein, the number of sequences produced thus far would be less than 1 out of a trillion trillion of the total number of events needed to give it even a 50% chance of success! Any reasonable person must conclude, then, that it is beyond the reach of chance to create even the smallest amount of new biological information in an organism. Add to this the fact that many new proteins are needed to produce new biological systems, and the scenario becomes all the more fantastical. If chance alone cannot produce the gene for even one protein—yet alone many—macroevolution becomes impossible.
While single point mutations cannot get the job done, what about whole gene duplication (when a gene is copied twice, thus becoming two identical genes)? Can this account for new biological information? No. The reason is simple: Duplicating a gene does not increase the net information content of the cell; it simply repeats existing information. Here is another reason: Duplicating a gene does not increase the net information content of the cell; it simply repeats existing information. Do you want more proof? Here’s a third reason: Duplicating a gene does not increase the net information content of the cell; it simply repeats existing information.
If you are paying any attention at all, surely you are saying to yourself, “That’s not three reasons, but one. You simply repeated yourself three times.” Exactly. That’s my point. Duplicating information cannot produce additional information. Saying, “gene duplication does not provide additional genetic information” two times does not double the information content of the sentence. It just repeats the same information twice. No new information is created. Likewise, duplicating a gene cannot increase the information content of the cell, and thus gene duplication cannot help an organism perform some new function. Trying to get new biological information/function by duplicating an existing gene is like thinking you can obtain an engine for your car by making a second steering wheel!
Gene Duplication + Point Mutations
While neither gene duplication nor point mutations can independently increase the information content of DNA, could they do so together? Some suggest that new information could be gained by gene duplication followed by numerous single point mutations over a long period of time, so that eventually the duplicated gene spells out a different biological message than the original.
There are numerous problems with this suggestion. It is highly unlikely that all point mutations will be beneficial. Consider something as simple as HTML code. If one randomly inserts, inverts, and deletes various characters in the code, what are the chances that every change will be beneficial? The chances are extremely low. The chances are overwhelmingly greater that most changes will be deleterious to the integrity and function of the code. Likewise, as soon as one or more harmful mutations accumulate in a critical region of the gene, the gene will either cease to function or function sub-optimally, affecting the organism’s fitness. And because energy is required to preserve this broken gene in subsequent generations, the organism’s overall fitness will decrease, or natural selection will eliminate the broken gene.
But what if – by chance – every mutation was a beneficial one? Over time, couldn’t the gene evolve to form new genetic information? Apart from the extremely unlikely possibility that the duplicate gene would experience beneficial – and only beneficial mutations – is it reasonable to think new genetic information could be gained through such a process? No, because the gene would need to remain functional throughout the evolutionary process (i.e. it must always convey a biologically functional message) if it is to provide a survival advantage to the organism nature can select for. How could this be done by changing one nucleotide at a time? While small amounts of information could conceivably maintain function while undergoing slight, successive evolutionary changes, it is inconceivable that the same could happen for large amounts of biological information. For example, we could evolve WORD into GENE one letter at a time and preserve meaning throughout the process:
But what if we had to evolve “gene duplication does not provide additional genetic information” into “we have to consider the fact that double point mutations are highly improbable” one letter at a time? How could the sentence retain some comprehensible meaning throughout the evolutionary process? It is impossible, and my analogy only contains 66 characters. Most genes contain hundreds of genetic characters! And yet for macroevolution to occur, this process would need to repeat itself millions of times over.
On a purely conceptual level alone, it seems inconceivable that random mutations could be responsible for macroevolutionary changes in organisms. Ultimately, however, it is the empirical data that must decide the matter. What does scientific research reveal about the power of random mutation to create biological novelties? How much biological change can it account for? We’ll take up this question in the next post.
If the mutations are harmful to the organism, they will result in a loss of information.
To make this number more meaningful, it is equivalent to 100 trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion trillion. Written out, it looks like this: 100,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,
William Dembski calculated this figure by multiplying together the number of elementary particles (1080), the number of seconds since the Big Bang (1016), and the number of particle interactions per second (1043).