Pseudogenes and the Origin of Humanity: A Response to the Venema Critique of the RTB Human Origins Model, Part 6
For over a month, I have been responding to biologist Dennis Venema’s criticisms of the RTB human origins model. (See: part 1, part 2, part 3, part 4, and part 5] to read my previous responses.) Venema recently issued another challenge to our model, this time focusing on the pseudogene evidence cited in favor of human evolution.
As Venema points out, when biologists compare the genomes of organisms they often find that the same pseudogenes appear in corresponding locations of genomes, juxtaposed to the same genes. Evolutionary biologists make use of shared pseudogenes to construct evolutionary trees, and, thus, take them as evidence for common descent. After all, why would an all-powerful, all-knowing, all-good Creator design the same nonfunctional, junk DNA sequences in seemingly related organisms? According to evolutionary biologists, the pattern observed for the distribution of pseudogenes makes better sense if life-forms evolved from a common ancestor.
I pointed out last week that this argument comes with a number of assumptions. For the pseudogene evidence to have potency: (1) pseudogenes must lack function; (2) their origin must be due to rare, random events; and (3) their juxtaposition to other genes must be arbitrary.
As it turns out, the latest discoveries raise questions about the validity of the assumptions necessary to conclude that shared pseudogene sequences evince biological evolution. But, as Venema notes in his critique, researchers have yet to discover function for unitary pseudogenes. According to Venema, this creates devastating problems for RTB’s human origins model. But is that the case? Can the RTB model make sense of shared junk DNA sequences that do not appear to have function?
The RTB Creation Model for Genomics
To address this question it’s necessary to first develop a model to account for the features of genomes from a creation perspective. What follows is the framework for RTB’s genomics model. The assumption that undergirds our model is that a Creator is responsible for life’s origin and history. As such, the genomes of organisms have been created via God’s direct intervention. But once created, genomes are subjected to physical, chemical, and biochemical events that can induce changes in their structure.
The RTB genomics model explains the similarities among organisms’ genomes in one of two ways:
- Reflecting the work of a Creator who deliberately designed similar features in genomes according to: (1) a common function; or (2) a common blueprint.
- Reflecting the outworking of physical, chemical, or biochemical processes that (1) occur frequently; (2) are nonrandom; and (3) are reproducible. (Go here and here to read articles defending this mechanism.) These processes cause the independent origin of the same features in the genomes of different organisms. (Along these lines, it is also interesting to note that researchers have discovered that horizontal gene transfer mimics the genomics signature for common ancestry. (Go here and here to read articles about this phenomenon.)
RTB’s model also explains genomes’ differences in one of two ways:
- Reflecting the work of a Creator who deliberately designed differences in genomes with distinct functions.
- Reflecting the outworking of physical, chemical, or biochemical processes.
In other words, the RTB model can account for similarities and differences in the genomes of organisms as either the deliberate work of a Creator or via natural-process mechanisms that alter the genomes after creation.
Next week, I will apply this model to the GLO unitary pseudogenes found in humans and chimps.
|Part 1 | Part 2 | Part 3 | Part 4 | Part 5 | Part 6|