Assessing the Ross-Rana Model

Assessing the Ross-Rana Model

Reasons to Believe (RTB) is among the most important organizations in the origins conversation. It is led by a wise leader, whom I deeply respect, Dr. Hugh Ross. I had the privilege of sharing the stage with him this last January, asking Are Humans Special?

Recently, I invited Dr. Fazale Rana from RTB into dialogue about their model of human origins. I made the claim that the recent work in population genetics we had done “falsified the RTB model.” The RTB model, also, has come up several times on the Peaceful Science Forums.  Several RTB supporters identify with Peaceful Science, and have been asking questions about it.

Retracting My Error

It turns out that I was wrong. That claim is retracted here. We did not falsify the current RTB model. Please accept my apology for an confusion my prior statements have caused. I was in error.

We did not falsify the current RTB model, just their first model, which was already falsified. I was able to begin conversations with Dr. AJ Roberts and Dr. Rana this last week, both before and at the Dabar Conference. It is not clear from the outside, but there is currently a range of RTB models, some of which might possibly comport with the genetic data. This story here is important, because even many RTB supporters do not know the progression here.

What is the RTB Model?

In the first RTB model, published in the first edition of Who Was Adam? in 2005, Dr. Ross and Dr. Rana lay out their first model. Among other details, they define “humans” as Homo sapiens, and insist there was no interbreeding between “humans” and other lines. This is a sole-genetic progenitor model, with Adam placed less than 100,000 years ago. Reading Scripture largely literally, they infer there is a lost record of agriculture over this time too. This model is what is commonly understood to be the RTB model, and we can say that this does not match with population genetics.

This, however, is not the current RTB model. In 2015, they published the second edition of Who Was Adam?, with several updates to the model. To their credit, they acknowledged and accepted the growing evidence for interbreeding between Neanderthals and Sapiens. They adapt their model, in light of this evidence, to acknowledge “bestiality” that arises in our lineage as a consequence of the fall. We might call of this an “Out of Africa and Hybridization” model of origins, where the hybridization is deemed against God’s wishes.

Not Sole-Genetic Progenitors

This model, whatever we call it, is not a sole-genetic progenitor model. Humans arise as a single couple, and the main trunk of humanity begins without genetic input from others. However, eventually, Adam’s offspring interbreed with Neanderthals and Denisovans. Now, we all descend from them as well. Some of us, maybe even most of us, have their DNA in our genomes alongside Adams. We all genealogically descend from Adam, but we are not entirely his genetic offspring. That means that we do not expect to see a genetic bottleneck in population estimates in the RTB model. To conclude that evidence against a single couple genetic bottleneck is against the single couple origin of Homo sapiens (and therefore against this model), is an example of the Ecological Fallacy or the Fallacy of Division.

It is entirely possible that the RTB model could be plausible in light of genetic evidence. Or, at the very least, it has not yet been tested. It might survive a careful test. Moreover, we are positioned now to test the RTB model by measuring the time to most recent 4 alleles (TMR4A) in the Homo sapiens specific lineage. I have the data now, and am looking forward to picking up the conversation with Dr. Rana at the end of summer. This is a really interesting question, of high importance in the origins debate. I’m very curious to see what the data will tell us.

I am holding off testing the model too soon. I want to do with this with Dr. Rana and Dr. Roberts. They are honest scientists, and want to bring them along with this. This is, after all, an effort of peace. In the end, also, I hope their model stands.

That Which Lies Ahead

I plan to look at the evidence myself. Will the RTB model stand? Or will it fall?

The more options available to others, the better. I commend Dr. Rana and Dr. Roberts for, without hesitation, wanting to see what the data shows. In the coming season, we might have some very interesting results to share. RTB, also, includes a range of views on Adam. So even if this specific model fails, it is possible another might work. This is a great moment for the RTB community. Help us understand at Peaceful Science what is the full range of views at RTB. Come tell us on the Forums how you imagine Adam. How large, exactly, is the RTB zoo of Adam models?

Several old earth creationists, including RTB supporters, hope that RTB “steals” the Genealogical Adam model too. They are more than welcome to include it as one option among many in their tent. Response from conservative theologians across the spectrum was positive. Maybe our insight into genetic vs. genealogical ancestry broadens the tent at RTB. After all, a Genealogical Adam does give them a way to affirm sole-genealogical progenitorship without bestiality, in the same timeline of a plain reading of Genesis.

RTB, also, already acknowledges that there were people outside the garden with whom Adam’s offspring eventually interbreed. Maybe this was not bestiality, but what God intended in the first place. So, in the coming year, let us consider together a Genealogical Adam and the current RTB model.

Come walk with us as we dream of Adam.

S. Joshua Swamidass

I am an assistant professor at Washington University in Saint Louis where I run a computational biology group. I'm also part of the dialogue between science and religion, through my work at BioLogos, the AAAS Science for Seminaries Program, and Veritas Forums.

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