Sunday, 26 August 2018

Hybrid Hominins! An individual with a Neanderthal mother and a Denisovan father

A letter [1] published 22nd August 2018 in Nature reports on the discovery of a bone fragment from a young female hominin whose mother was Neanderthal and whose father was Denisovan. That hybridisation between hominin species occurred in the past is no longer in question, but this discovery provides evidence of a first-generation cross between two different hominins, something which in itself is remarkable. Studies like this are no longer necessary to falsify creationist assertions about human origins as the evidence against universal human descent from two people living six thousand years ago is overwhelming, but to have evidence of a first-generation cross between two different hominin groups further underscores how human origins is far more amazing and complicated than the special creationist can imagine.

Monday, 13 August 2018

A flat Earth? That's what a literal reading of the Bible reflects...

One common strategy fundamentalists employ is an appeal to a literal reading of the first creation narrative to prove that the universe was really created in six literal consecutive days. [1] Of course, as we've known for quite some time, the universe is nearly 14 billion years old, the Earth is 4.6 billion years old, and the sequence in which life appeared on Earth contradicts the sequence in Genesis 1, so a literal reading is falsified by hard evidence.

Fundamentalists however are determined not to let something as trivial as hard facts get in the way of a literal interpretation of the Bible elevated to the status of dogma, so the usual response is to retreat to hard fideism, and simply ignore the facts. Science is after all merely the 'wisdom of men' and can routinely be ignored when inconvenient. Where things become problematic for the YEC literalist is that they are almost always [2] believers in a spherical earth and a heliocentric cosmology. As has been stated many times, a truly consistent reading of the Biblical references to the nature of the universe would require the fundamentalist to believe in a flat, fixed earth. I have yet to encounter a YEC who is able to defend heliocentrism and a spherical Earth purely from the Bible, which of course means the non-flat earth, non-geocentrist YEC is placing science above the literal word of the Bible. [3]

Sunday, 8 July 2018

The genetic scars of our insect-eating, egg-laying past - the powerful genomic evidence of common descent

The earliest mammals are believed to have been insect-eaters, which means that they would have had the genes for chitinase, an enzyme that digests chitin, the polysaccharide which is the main component of insect exoskeletons. Given this, common descent would predict that non-insectivorous mammals, which no longer need to digest chitin, would no longer have functioning chitinase genes, but instead have chitinase pseudogenes as inherited remnants of their insect-eating past.

Recently, Christopher Emerling, Frédéric Delsuc, and Michael Nachman published a paper in Science Advances in which they showed that in all the carnivorous and herbivorous animals whose genomes they examined, they found not only chitinase pseudogenes, but in animals previously known to share common ancestry, they found exactly the same mutations in some of the chitinase pseudogenes.

Regular readers of the website will be well-aware of the power of this argument; shared identical genomic 'errors', be they pseudogenes, endogenous retroviral elements, or retrotransposons are some of the strongest lines of evidence confirming common descent. Just as shared identical sections in exam papers confirm copying and cheating in students (identical independent errors are of course so unlikely an explanation as to be readily dismissed out of hand), so do shared identical genetic errors confirm the inheritance of a 'broken' genomic elements from a common ancestor of the species examined.

Similar evidence can be found from examples such as broken egg yolk protein genes in placental mammals, broken olfactory receptors in aquatic mammals such as whales, broken tooth-enamel genes in toothless animals, and the broken vitamin C synthesising gene GULO in humans and primates. These previously-mentioned examples made the case for common long ago, but papers such as this are invaluable if only to show the power of evolutionary theory in its ability to make predictions, and explain facts.

Sunday, 1 July 2018

Removal of Francisco Ayala book from "Recommended Reading" List

Geneticist Francisco J. Ayala's book "Darwin's Gift to Science and Religion" was in my list of recommended reading, but after an investigation found he had sexually harassed both faculty and graduate students, I have removed it from the list. Citing articles written or co-written by Ayala - who prior to this was a highly-respected geneticist - is one thing, but I don't feel comfortable recommending a book he has written in the light of this revelation.

Sunday, 17 June 2018

"Ken Ham made me an atheist" - yet more reaons why evolution denialism erodes faith

Former young earth creationists who lose their faith after critically examining the tenets of YEC and finding them wanting are sadly numerous, with their stories depressingly alike. They were devout fundamentalist Christians whose loyalty to their community was unquestioned, whose faith began eroding when they began looking into YEC, and found that the standard fundamentalist anti-evolution arguments were unconvincing, pathetic, and intellectually dishonest. This, I have to point out, is without looking at a single mainstream scientific source attacking creationism.While there will always be people who will blindly follow the claims made by the elders in their faith tradition, what fundamentalists consistently fail to grasp is that there will always be curious, intellectually honest members who will critically examine the foundations of YEC and find them non-existent.

Thursday, 24 May 2018

No, hominin fossils are not all the same.

Given that anti-evolutionists in our community are invariably extremely poorly informed on even the basics of palaeoanthropology, I am not surprised to see sweeping statements such as "there is no evidence that Neanderthal man existed", uncritical repetition of creationist aphorisms such as "all life breeds after its own kind" or even "there are no different species of humans, only different races." Anyone who makes these assertions is positively shouting the fact that they know nothing of the subject at all. The morphological differences between humans and Neanderthals are clear and unmistakable. Furthermore, we now have the Neanderthal genome, which is clearly distinct from that of the human. Both anatomy and genetics confirm that Neanderthals existed, and were clearly different from us. In this post, I will summarise this information.

Wednesday, 23 May 2018

A million years of hominins in the Middle East

In my last post, I pointed out that as a medical professional educated in the genomics era, evolution denialism is simply not an option. The evidence against universal human descent from two people a mere six thousand years ago and for human-ape common ancestry just from human genetics is overwhelming.  This is however not something exclusively restricted to believers who are medical or life sciences professionals. Anyone who studies science at high school or takes an interest in natural history will be well aware of the evidence for human antiquity stretching back far beyond six thousand years. While a parental scrawl of "Not True!" in the "Human Evolution" section of the family copy of the Junior World Encyclopaedia may have been enough forty years ago, given the widespread availability of material on human evolution today [1-8], the fundamentalist battle to censor palaeoanthropology has been lost before it even starts.

Fundamentalists assert, based on a highly literal reading of the creation narratives, that the human race began 6000 years ago in south-west Asia. However, what the archaeological and palaeoanthropological data from this area show is that not only does evidence of human settlement in this area extend back well before 4000 BCE without any evidence of discontinuity, human fossils can be found back well over 100,000 years ago, with hominin fossils appearing in Turkey around one million years ago. It is impossible to dogmatically assert that no human was alive more than six thousand years ago, Adam was the first human being to exist or that every human who has ever lived descended exclusively from Adam. Just the fossil evidence from the near East flatly refutes these dogmatic assertions, and pretending they do not exist or threatening to excommunicate people who point out these facts will not make them go away.