David: I was specifically looking for remnants of metazoan-specific genes in protozoa, not the rare example of a functional form of a gene. Where are the remnants? Perhaps my example of RTKs was not the best as there appears to be an example of an RTK in tetrahymena, but there are many other examples of metazoan-specific genes, or vertebrate-specific genes. Again, where are the remnants of these genes in protozoan and bacterial genomes.

Given the way so many people engage in revisionism, it was refreshing to see one scientist acknowledge that the “evolutionary perspective” is (was) that tyrosine kinases are “a distinctly metazoan innovation.” But why dismiss the RTK example after bringing it up? His example wasn’t a good one, I suppose, because it turned out that I had the “sort of evidence that one would have to produce for the idea of front-loading to be taken seriously.” And there is a growing list of genes that were once thought to be distinctly metazoan innovations, co-evolving into existence along with the origin of metazoan. But as this blog has been documenting, more and more of these genes appear to be present in unicellular organisms, just as we would expect if evolution was front-loaded. Are we also supposed to ignore all these other examples?

Mike Gene’s response (see ping-back) to my question regarding genomic remnants predicted by front-loading of genetic information was to identify a rare example of a functional protozoan gene once thought to be metazoan-specific. This was not an honest engagement of either my question, or the prediction made by front-loading. It was just a diversionary tactic. Again, I ask, where are the remnants of metazoan genes within the genomes of protozoa? The question speaks to the issue of genomic decay that we know occurs in the absence of functional selection.

As anyone who has read The Design Matrix knows, I dismiss the notion that you can front-load useless genes that will only become useful hundreds of millions of years later. And I do so for the very reason David cites - the issue of genomic decay that we know occurs in the absence of functional selection. The whole idea is how a designer would get around this problem and I outline the logic and solutions in chapter 7.

Why would anyone dismiss actual genes or domains, crucial to metazoans and previously thought to be metazoan innovations, and instead search for fragments of useless of pseudogenes? Remember that when we sequence the genomes of protozoa today, we are not sequencing the genomes of ancient, primitive organisms. We are sequencing the genomes of the evolved descendents of ancient ancestors. For example, metazoans are thought to have originated around 800 million years ago. If a unicellular organism from 800 million years ago had genes that can only be useful in a metazoan state, those genes would be pseudogenes in any protozoan and pseudogenes are completely erased over a time span of ca. 50 million years. What this means is that any remnants of metazoan-only genes in the lineage of Tetrahymena, for example, would have disappeared hundreds of millions of years ago.

On a final note, it is disappointing that Levin would mischaracterize my honest engagement as being dishonest. There is no need for this type of personal attack.