Literalists deny evolutionary science is a thing. They don’t realise there is far more than this one branch of science stacked against them. Genetics is not as simple as peas in a pod, but even a basic understanding rules out Adam and Eve as the universal ancestors. It’s all to do with gene variations (called alleles), which we get at most two copies of one from Mum and one from Dad (sometimes the two are the same). Dennis Venema has provided a readily accessible explanation of why genetic variation cannot work with the literalist story.
In a highly recommended and simple article, Dennis is responding to a young earth creationist critiquing Venema & Scott’s book “Adam and the Genome”. Part of the blog post is reproduced below:
one individual can only have at most two alleles of any gene. A population reduction to one breeding pair would mean that at most, four alleles of a given gene could pass through the bottleneck – in the case where both individuals are heterozygous, and heterozygous for different alleles. The population would then have to wait for new mutation events to produce new alleles of this gene – a process that will take a significant amount of time. Since this would happen to all genes in the genome at the same time – a reduction to a maximum of four alleles – we would notice this effect for a long time thereafter as genetic diversity was slowly rebuilt across the genome as a whole.
So, a bottleneck to two individuals would leave an enduring mark on our genomes – and one part of that mark would be a severe reduction in the number of alleles we have – down to a maximum of four alleles at any given gene. Humans, however, have a large number of alleles for many genes – famously, there are hundreds of alleles for some genes involved in immune system function. These alleles take time to generate, because the mutation rate in humans is very low. This high allele diversity is thus the first indication that we did not pass through a severe population bottleneck, but rather a relatively mild one (estimated, as we have discussed, at about 10,000 individuals by current methods).
Another effect that a bottleneck to two individuals would produce is that there would be no rare alleles after the bottleneck. All alleles would have a frequency of at least 25%. As the population expanded after such an event, those alleles would stay common, and only new mutations would produce less common alleles. What we observe in humans in the present day is that many alleles are rare – even exceedingly rare. The distribution of alleles in present-day humans looks like it comes from an old, large population – not one that passed through an extreme bottleneck within the last few hundred thousand years, which is when our species is found in the fossil record. Thus the observation that we have many alleles of certain genes and the distribution of allele frequencies both support the hypothesis that humans come from a population, rather than a pair.
Now I am a creationist. So is Venema. However the evidence within our own bodies, bodies created by God, disputes the so called literalist reading of Gen 1-3. This evidence is not some pie in the sky or blackboard scratchings. The genetic evidence links straight into observable medical phenomena, it even directly links us to human remains up to 15,000 years old. Nor is this evidence alone. Archaeology has comprehensively disproved the 6,000 or even 10,000 year old reading of Gen 1-3 through Australian aboriginal sites as well as natural wonders.
Rather than deal with the facts, too many creationists reject any evidence but their tradition and preferred interpretation of the biblical record (no matter that their methodology is inconsistently applied). Responding to reality with threats and disfellowshipping actions is damaging. Already a number of Christadelphian meetings have been severely damaged by those with a zeal for God which is not according to knowledge. Rather than accepting the Lord’s counsel about handling a situation when WE there are wheat and tares present, they have executed judgment.
Christ had room for honest doubters (“Lord help thou mine unbelief” surely some of the sweetest words in Scripture) and explorers. Evolutionary Creationists – despite the rhetoric – are not even that troubled. There is room in the house of Christ for graciously allowing space for those who accept God’s ways are seen in His Word and works and who try to reconcile the two. Such questions and explorations are no threat to Aunty Mavis sitting up the front of the hall each Sunday – provided so called literal creationists cease preaching fire and brimstone against their brethren and sisters from pulpit and magazine.
Like it or not, the evidence from many different fields points inevitably to one conclusion. This evidence is no longer hidden in a dusty academic corner but is increasingly part and parcel of modern life with a myriad of practical applications. The sooner people accept God’s reality the better.