A Facebook friend from time to time posts links to the Discovery Institute’s Evolution News blog. Much thanks. I need to keep up.
Evolution News has a number of authors, mostly notable creationists. These would include Stephen C. Meyer, Michael Behe, John West, and Jonathan Wells. This item was posted by Ann Gauger:
Ann Gauger is a zoologist with a BS in biology from MIT and a 1989 PhD from the University of Washington. As a post-doctoral fellow at Harvard she cloned and characterized the Drosophila kinesin light chain. Her research has been published in Nature, Development, and the Journal of Biological Chemistry. She also has a number of years of experience as a homeschool teacher.
From Evolution News:
Is There a First Human Couple in Our Past? New Evidence and Arguments
Dennis Venema is associate professor at Trinity Western University. His book Adam and the Genome is under active discussion here and over at BioLogos. The central question implied in the title of that book is: does our genome rule out Adam? Could humanity have had its origin in a first pair, or did it have to come from a population of at least several thousand?
This question has been addressed by numerous scientists in the past, ever since human genetic data began to roll in. And all of them, as far as I know, have said that yes, our genome rules out Adam. We are the product of common descent. We are descended from an ape-like population of at least several thousand. This we have heard before.
Now here’s where it gets interesting. There has been a debate going on over at BioLogos for a number of months that was triggered by Venema’s book. The debate is about whether there could have been a bottleneck of two at some time in the human past. This discussion was started when Richard Buggs, Senior Research Leader (Plant Health) at Royal Botanic Gardens Kew, and Reader in Evolutionary Genomics at Queen Mary, University of London, challenged Dennis Venema about what Venema wrote in Adam and the Genome. Venema had argued:
As our methodology becomes more sophisticated and more data are examined, we will likely further refine our estimates [of human population size] in the future. That said, we can be confident that finding evidence that we were created independently of other animals or that we descend from only two people just isn’t going to happen. Some ideas in science are so well supported that it is highly unlikely new evidence will substantially modify them, and these are among them. The sun is at the center of our solar system, humans evolved, and we evolved as a population.
Put most simply, DNA evidence indicates that humans descend from a large population because we, as a species, are so genetically diverse in the present day that a large ancestral population is needed to transmit that diversity to us. To date, every genetic analysis estimating ancestral population sizes has agreed that we descend from a population of thousands, not a single ancestral couple. Even though many of these methods are independent of each other, all methods employed to date agree that the human lineage has not dipped below several thousand individuals for the last three million years or more — long before our lineage was even remotely close to what we would call “human.” Thus the hypothesis that humans descend solely from one ancestral couple has not yet found any experimental support — and it is therefore not one that geneticists view as viable. [Emphasis added.]
The image above appears at the head of Gauger’s Evolution News posting. It’s a painting from centuries ago titled “Adam and Eve” or something close to that.
I have previously reviewed the book Adam and the Genome by Dennis R. Venema and Scot McKnight. The summary of the book is that the creationists have it all wrong, the human species did not descend from a single pair of humans, but is the most recent of a lineage stretching back billions of years. However, God does exist, and God is responsible for all this.
Update: I am adding some material of interest.
Gauger mentions she has previously discussed this point.
So TSP is not validated for these highly polymorphic genes, HLA-DRB1 in particular, and convergent evolution (or original diversity) is validated. I addressed, by the way, the question of HLA-DRB1’s polymorphism and TSP, and a first human pair, in the book Science and Human Origins (2012). That book was written after I discovered that Francisco Ayala’s argument against the possibility of a first pair based on HLA-DRB1 did not stand up. My hypothesis about a first pair was based on what I saw in papers about HLA-DRB1, most notably this and this, but the hypothesis was more suggested than demonstrated. I am glad to see that some of what I wrote has been substantiated.
See below for an expansion of TSP. The book in question has five parts, written separately by Gauger, Douglas Axe, and Casey Luskin. Gauger contributed chapters 1 and 5. Chapter 5 relates to the topic of her posting:
THE SCIENCE OF ADAM AND EVE
Using population genetics, some scientists have argued that there is too much genetic diversity to have passed through a bottleneck of just two individuals. But that turns out not to be true.
IN CHAPTER 1, I ARGUED THAT OUR SIMILAR ANATOMY AND DNA sequences are not sufficient to demonstrate that we share a common ancestor with chimps. Using peer-reviewed scientific literature about transitional fossils, and what is known about current chimp and human anatomy, I concluded that there are too many anatomical changes and too little time for neo-Darwinian processes to have accomplished the supposed transition from our last common ancestor with chimps to us.
But the current challenge concerning our origins involves more than fossils, anatomy, and improbable Darwinian scenarios. Now that DNA sequencing has become relatively simple and cheap, researchers are gathering vast amounts of human sequence data. They use the genetic variation they find to reconstruct past events in our genetic history. They derive evolutionary trees, estimate ancestral population sizes, and even calculate when and where our ancestors migrated out of Africa. Based on this kind of work, some have argued that we cannot have come from just two first parents.
[Location 2102 in the Kindle edition]
Gauger wants to take exception to the first part. Evidence that points to human origins from a collection of a few thousand individuals is not conclusive. The original pair of humans is not ruled out by modern research. The sum total of the piece is a glaring heap of wishful thinking, as would be evident to people knowledgeable of the subject and taking time to run down all Gauger’s arguments. And that I will leave to others, since it is beyond the scope of my expertise to critically evaluate the opposing arguments. I will just get to Gauger’s concluding statement:
So let me restate: the best explanation for the similarity among alleles is convergent evolution (or possibly original diversity), and not TSP. Finally, this analysis is strong evidence that TSP does not rule out a bottleneck of two.
To sum up, it’s very simple.
- A bottleneck of two that is older than 500,000 years ago cannot be ruled out. That does not mean such a bottleneck ever existed, but rather that the possibility cannot be excluded. Future models may change that number of 500,000 years, up or down.
- This is based on an analysis of the genetic data run by Drs. Schaffner and Swamidass, themselves evolutionary biologists and not ID supporters.
- In addition, the bottleneck hypothesis stood up to a test using TSP (trans-species polymorphism). The test showed TSP was due to convergent evolution. This was a surprise to Dr. Swamidass.
- A bottleneck of two, or a first pair at our origin older than 500,000 years, is possible.
- Evolutionary biologists, including Dennis Venema, can no longer say we had to come from a population of 10,000 at any time over the last 3 million years.
Obviously, there is no rigorous science being argued here. This amounts to a special pleading for religious belief, particularly for biblical truth. Along that line, Gauger is not attempting to sell the full load. The Bible recounts the origin of the human race from two people. Gauger stops there. She lets slide the remainder of the story—that all this happened little more than 6000 years ago. Lady, if you’re in for a penny, you need to be in for a pound.
It’s an interesting twist we are observing. In days gone by—actually, in decades gone by—those people at the Discovery Institute sought to sell Intelligent Design as legitimate science, devoid of religious indoctrination. They seem to have thrown that notion over and have now gone full Monty pushing for the Abrahamic religions, particularly Christianity. At times the openness can be refreshing.