Human Population Bottleneck Admitted by Secular Geneticists

Secular scientists now claim that the
human population almost died out.
Does this match the Biblical record?

A headline in Science on Aug 31, 2023 shouted, “Did our ancestors nearly die out?

The Bible claims such a population bottleneck at the Flood of Noah, when only eight people survived to repopulate the earth. Secularists deny the Flood, and their new claim of a population bottleneck, based on genetic evidence, is far different. They believe it happened long ago among pre-human hominids. The new estimate by Hu et al. is significant, though, in changing opinion about the history of early humans.

The results suggest that our ancestors suffered a severe population bottleneck that started around 930,000 years ago and lasted for almost 120,000 years. This is estimated to have reduced the number of breeding individuals to ∼1300, bringing our ancestors close to extinction.

Theistic evolutionists, such as those in the Darwinism-affirming group Biologos, have denied the Flood bottleneck, arguing that eight people could not provide enough genetic diversity to prevent inbreeding and lead to a healthy human population. For that matter, they also argue that a single pair, Adam and Eve, could not have populated the earth. This new admission has raised discussion about whether or not population bottlenecks as small as those recorded in Genesis could allow them to “be fruitful and multiply, and fill the earth” as God commanded (Genesis 9:1-7).

Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition (Hu et al., Science, 31 Aug 2023). This is the paper raising the discussion. A reading shows many assumptions going into the calculations of dates and population sizes, which cannot be known without a time machine.

The ancient severe bottleneck was not detected in previous SFS-based analyses. This failure might be due to the use of predefined demographic models. In this study, we found that the likelihood must be accurately calculated to detect the severe bottleneck (fig. S1). The use of other methods such as Stairway Plot—which may not have sufficient resolution power for estimation of ancient population size history—is another possible reason for the failure.

Estimates like this depend on models with inputs that cannot be accurately known. The authors admit, “ancient population size history of the genus Homo during the Pleistocene is still poorly known, although it is essential for understanding the origin of the human lineage.”

The Table of Nations (Genesis 10) tells how descendants of Noah migrated in different directions after the Flood. The Tower of Babel dispersion is described in Genesis 11.

Evolutionists do, however, postulate “founder events” with few breeding pairs when animals migrated to new habitats, such as islands. Last year, UC Berkeley suggested that “bottlenecks that reduced genetic diversity were common throughout human history.”

Richard Buggs of Queen Mary University, a Christian who describes himself as an “evolutionary biologist and molecular ecologist,” asks if science is moving closer to Adam and Eve. His blog post the day after the Science paper describes how the findings are making the Genesis account more plausible. He also relates his discussions with interlocutors are Biologos who have denied the possibility of a single pair leading to the human race.

The methods used in the study published in Science yesterday are similar to the older methods in that they also cannot detect short sharp bottlenecks. They rely on the assumption that the human population size was stable over time windows lasting many generations, in order to calculate an effective population size for that time window. Thus, a bottleneck of two is not ruled out by their methods. In some ways, the single-couple hypothesis becomes more plausible given the new evidence for a prolonged bottleneck with an average effective population size of about 1280.

Caution is still advised, though, he says: “Such methods are not able to either prove or disprove the hypothesis of Adam and Eve.” In an embedded YouTube video, Dr Buggs gives more details on how limited genetic diversity can produce wide variation without becoming subject to inbreeding failure.

In the Journal of Creation in 2018, Robert Carter answered whether the eight people after the Flood could have led to all the genetic diversity in the human population today.