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Quintessence of Dust

Quintessence of Dust explores science, society, and human nature, focusing on genetics, development, evolution, neuroscience, systems biology, and topics related to scientific literacy. I occasionally discuss intelligent design, creationism, science denial, and other political/social influences on scientific literacy. Additional topics: philosophy, baseball, scientific culture, and Shakespeare. My main theme is scientific explanation.
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IntroductionBiologiaInglese
Pubblicato
Autore Stephen Matheson

It's early January 2023, a little before sunset in Tucson. Live image below, showing the glorious Santa Catalina mountains (the snow on the upper reaches is more apparent earlier in the day) and my dinner preparations (shrimp and veggies on the grill). I've decided to start writing here at Quintessence of Dust , after another long hiatus. Here are some of my reasons.

BiologiaInglese
Pubblicato
Autore Stephen Matheson

Can a new protein-coding gene be born overnight? That's the theme of this series. The answer, remarkably, is yes, and the Arhgap11b gene is the recent case I'm considering. After surveying the ways that this could happen, I narrowed the possible mechanisms to three: Before looking at the details, let's take note of the fact that the genomes of animals and plants typically have gigantic amounts of DNA that does not code for protein.

BiologiaInglese
Pubblicato
Autore Stephen Matheson

In my previous post I attempted to identify all the ways that a new gene can come about, after defining what I meant by "new" and "gene." Two questions came up, one a comment on the post, and the other via Facebook. 1. What about exon shuffling? Isn't that a mechanism by which new genes are made?

BiologiaInglese
Pubblicato
Autore Stephen Matheson

What would it take to make a completely new gene? Interesting question, but first let's agree on roughly what we mean by a "new gene." Here is how I defined the topic when discussing unique human attributes: "Creation of Eve." Was she completely new? So you see we mean something a lot more "new" than, for example, the human-specific version of the FoxP2 gene, which I have discussed before. And we mean something that is born overnight.

BiologiaInglese
Pubblicato
Autore Stephen Matheson

The human brain is often described using literally cosmic superlatives. Here is V.S. Ramachandran, a renowned neuroscientist: That's some serious complexity there, yes, but hidden in the description is a mundane reality: the human brain is made of neurons which make synapses with other neurons, which means that it's made of the same stuff as the brain of a sloth or a goldfish or an earthworm.

BiologiaInglese
Pubblicato
Autore Stephen Matheson

Quintessence of Dust has been on hiatus for more than five years. It's time to resurrect it. Why now? Because it's 2017, and 2017 is not a time to be quiet. The first project involves some remodeling. Quintessence of Dust was built almost ten years ago, with a set of themes and goals that don't all fit in 2017.

DesignSelectionBiologiaInglese
Pubblicato
Autore Stephen Matheson

The folks at the Discovery Institute (DI) are engaged in an extensive attempt to rebut my friend Dennis Venema's critiques of Stephen Meyer's surprisingly lame ID manifesto, Signature in the Cell . There are several aspects of this conversation that I hope to address in the coming days and weeks, but one jumped out at me today: the consistent confusion about natural selection in depictions of evolutionary theory by design advocates.

Common DescentGeneticsMutationVariationBiologiaInglese
Pubblicato
Autore Stephen Matheson

Human evolution has been in the news quite a lot recently. New genetic data suggest that ancient humans included both Neanderthals and Denisovans, which colonized different parts of the world but subsequently interbred with so-called modern humans and left telltale traces of this history in the genomes of living humans.

Bad GenesDeleterious MutationsGeneticsGenomeMutationBiologiaInglese
Pubblicato
Autore Stephen Matheson

Genetic hitchhiking is thought to be an inevitable result of strong positive selection in a population. The basic idea is that if a particular gene is strongly selected for (as opposed to selected against), then the chunk of the genome that carries that gene will become very common in the population.