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Thursday, October 29, 2026

Defining a gene: the selfish Mendelian gene and the molecular gene

I recently commented on an article in Nature by Nathaniel Comfort where he criticized Dawkins' book The Selfish Gene. I also criticized Jerry Coyne's response because he (Coyne) failed to mention the most serious issue with Dawkins' book; namely, his (Dawkins) failure to give adaquate coverage to neutral theory and random genetic drift. [The Selfish Gene: a critic and a defender are both wrong!

Coyne quickly corrected that omission with a post the next day: The Neutral Theory: a genuinely important supplement to evolution’s “Modern Synthesis”.

Comfort made many mistakes but one of them was praising Philip Ball's book How Life Works. This prompted Ball to respond to my blog post by giving us a link to his own review on the Scientific American website: The Selfish Gene, revisited.

Tuesday, October 27, 2026

The Selfish Gene: a critic and a defender are both wrong!

Richard Dawkins published The Selfish Gene in 1976 and in 2017 the Royal Society conducted a popular poll that voted it the most inspiring science book of all time.

I don't think that book is a good representation of modern evolutionary thinking and I've expressed that opinion many times on this blog [The selfish gene vs the lucky allele] ["The Selfish Gene" turns 40] [The "selfish gene" is not a good metaphor to describe evolution] [Die, selfish gene, die!].

The issues are complicated—here's how Dawkins described his book in the 1989 edition.

The selfish gene theory is Darwin's theory, expressed in a way that Darwin did not choose but whose aptness, I should like to think, he would instantly have recognized and delighted in. It is in fact a logical outgrowth of orthodox neo-Darwinism, but expressed as a novel image. Rather than focus on the individual organism, it takes a gene's-eye view of nature. It is a different way of seeing, not a different theory.

My objections are that the book is far too adaptationist and too "Darwinian." It fails to convey the complications of evolution to the general public, including the dominance of chance, accident, and contingency. It misrepresents some views of evolution, especially punctuated equilibria. It focuses too much on genes (alleles) as the unit of selection (evolution?) at the expense of individuals, groups, and species. (Species sorting may not be important but it deserved more than passing dismissal.) It focuses too much on the evolution of animals, especially animal behavior and that feeds into the biases of the general public who know very little about the vast majority of species outside of the animal kingdom.

"Atheism of the gaps" or how to misrepresent atheism and abuse philosophy

I am an atheist. That means I don't believe in god(s). I also don't believe in Santa Claus, the tooth fairy, Bigfoot, the Loch Ness monster, or leprechauns.

When I say that I don't believe in leprechauns it means that I don't devote any time at all to the idea that leprechauns might exist and I don't alter my life in any way to allow for that possibility. If you ask me in casual conversation, I might say that leprechauns don't exist.

But I will give you a different answer if you are a philosopher or someone steeped in philosophical musings. In that case I will be careful not to say that lepechauns don't exist because I'm well aware of the fact that you can't prove a negative.

Sunday, October 11, 2026

Can DNA fingerprints distinguish between identical twins?

The other day we were watching one of our favorite British crime shows where science and forensics plays a prominent role in catching the criminal.

This one involved a complicated story line with three identical triplets who impersonated each other.1 DNA was present at one of the crime scenes and it matched the DNA of the triplets but the investigators weren't able to distinguish between the three triplets. I knew that monozygotic twins and triplets had identical DNA fingerprints but I also knew that it was possible to tell them apart if you had more DNA sequences.

A typical DNA fingerprint consists of amplifying selected regions of the genome using PCR. These regions contain short tandem repeats (STRs) consisting of multiple stretches of identical sequences such as AGGCCT or CGCGAT. Individuals differ in the number of these repeats and hence the length of DNA that contains them and this length can be easily detected. The best DNA fingerprint techniques look at about 30 different STR regions and the chance that all 30 will be identical in size in unrelated individuals is extremely low.