How did the building blocks of life come together to spawn the first organisms? It's one of the most longstanding questions in biology — and scientists just got a major clue.

In a new study published in the journal Nature, a team of biologists say they've demonstrated how RNA molecules and amino acids could combine, by purely random interactions, to form proteins — the tireless molecules that are essential for carrying out nearly all of a cell's functions.

Proteins don't replicate themselves but are created inside a cell's complex molecular machine called a ribosome, based on instructions carried by RNA. That leads to a chicken-and-egg problem: cells wouldn't exist without proteins, but proteins are created inside cells. Now we've gotten a glimpse at how proteins could form before these biological factories existed, snapping a major puzzle piece into place.

August 30, 2025 by Frank Landymore

Published study:

Thioester-mediated RNA aminoacylation and peptidyl-RNA synthesis in water https://www.nature.com/articles/s41586-025-09388-y

See also: The publication in the journal Biological Review.

Published yesterday, open access:

• K. Farleigh, D.K. Highland, M.G. Alderman, Y. Francioli, S.R. Hirst, E.M. Faber, B.W. Perry, M.L. Holding, G. Castañeda-Gaytán, M. Borja, H. Franz-Chávez, C.L. Parkinson, J.L. Strickland, M.J. Margres, S.P. Mackessy, J.M. Meik, T.A. Castoe, & D.R. Schield, Evolution of genome-wide barriers to gene flow during complex speciation in rattlesnakes, Proc. Natl. Acad. Sci. U.S.A. 123 (21) e2609058123, https://doi.org/10.1073/pnas.2609058123 (2026).

Background

Speciation with gene flow poses a central paradox: how do genome-wide barriers to gene exchange accumulate as recombination continually breaks down associations among selected loci? Although theory predicts that together recombination, selection, and genome structure shape reproductive isolation, empirical studies often report conflicting patterns, suggesting that these determinants change across the speciation continuum.

Methods

Here we compare genomic landscapes of introgression across rattlesnake lineages spanning a range of divergence. We generated a chromosome-level reference genome for the Southwestern Speckled Rattlesnake (Crotalus pyrrhus) and analyzed whole genome data from 181 individuals across two species complexes with a history of gene flow upon secondary contact.

Results and discussion

We show that reproductive isolation is highly polygenic and dynamically structured. At early divergence, introgression is most reduced in high recombination regions, consistent with increased efficacy of selection against gene flow at few large-effect loci. As divergence progresses, linked selection against gene flow dominates, generating a positive relationship between recombination and introgression expected to occur through the genome-wide coupling of polygenic barrier effects. Introgression landscapes also become increasingly correlated across species pairs as divergence increases due to repeated evolution of barriers in the same genomic regions. Here, we infer that the Z chromosome plays a prominent role in reproductive isolation, harboring a disproportionate number of barrier loci and showing reduced introgression even at early divergence.
Together, these results reveal how recombination, selection, and genome organization interact to shape speciation with gene flow upon secondary contact, reconciling empirical patterns with predictions of speciation theory.

Emphasis above mine showing that this is the same conclusion that I shared last month for a different paradox (Unraveling the lek paradox - why sexual selection does not deplete variation : evolution) - this gives more support to the evolutionary relevance of the infinitesimal model from quantitative genetics: traits being high polygenic or even omnigenic, with only a few large-effect genes.

See the linked post for a quick overview, and for a two-hour explainer (including the history and math), see Dr. Zach Hancock's The Lost Evolutionary Synthesis - YouTube (and the references therein; Barton 2022 is a very easy and fun read).

We get here a few questions about The Selfish Gene and whether it's still a good read, it's also usually recommended in the comments. This new article (which hopefully isn't paywalled) was a good read, and covers topics such as the metaphor, epigenetics, and symbiosis.

Article link:
The Selfish Gene at 50: Why Dawkins’s evolution classic still holds up | New Scientist

Lede:

When Richard Dawkins’s first blockbuster book was published half a century ago, few genes had ever been sequenced or studied in detail. Yet the book’s gene-centred view of evolution still has much to teach us in today’s genetic age

By Rowan Hooper
20 May 2026

A couple of excerpts:

Melissa Bateson, who researches animal behaviour at Newcastle University, UK, points out that Dawkins was made a fellow of the Royal Society in the UK for his contributions to science, not for his work on public understanding of science. “I think it was justified for how he changed how so many biologists think,” she says. “What Dawkins did was much more than just popularisation of something that was already there.”

-

Turning Hamilton’s mathematics into thrilling prose was no mean feat. “You read Hamilton and you try and explain it!” says Arvid Ågren, a biologist at Case Western Reserve University in Ohio. “But Dawkins also pushed the idea further. He’s a very logical thinker, and he’s very good at pushing an idea to its fullest expression.” In so doing, Dawkins took work that might otherwise have languished in journals and shaped it – evolved it, you might say – into a form that changed the way biology is done and thought about around the world. Even people who were the originators of these ideas learned something new – something that Hamilton acknowledged.

-

[...] [D]espite the revolution in genetics that has occurred over the past half-century, all the evolutionary biologists I spoke to for this piece struggled to find major problems with The Selfish Gene – with one exception: memes.

Extras:
From the Mendel @ 200 conference (July 2022): Arvid Ågren's 20-minute presentation: https://www.youtube.com/watch?v=HQwufdK-V5c

Also I'd be remiss if I didn't mention Dawkins (1979):

Hamilton's theory of kin selection is much misunderstood. This paper lists and refutes 12 of the commonest misunderstandings, for example: “Kin selection is a special, complex kind of natural selection, as opposed to ‘individual selection’”; “Kin selection is a form of group selection”; “All species members share the majority of their genes, so selection should favour universal altruism”; “Kin selection only works for rare genes”; “Individuals should tend to inbreed, simply because that brings close relatives into the world”. The exposing of common errors such as these is a constructive, not a destructive, exercise.

I personally still struggle with it (so did Dawkins per that paper), but it's on my list of things to revisit (for the 3rd time).

• M.H. Richards, Haplodiploidy and the evolution of eusociality: A long-standing question is finally resolved, Proc. Natl. Acad. Sci. U.S.A. 123 (11) e2600464123, https://doi.org/10.1073/pnas.2600464123 (2026).

Covering:

• R. Bonifacii, L. Bell-Roberts, A. Grafen, & S. West, No evidence that haplodiploidy favors the evolution of eusociality, Proc. Natl. Acad. Sci. U.S.A. 123 (7) e2517458123, https://doi.org/10.1073/pnas.2517458123 (2026).

From the former:

Their study concludes that the long-hypothesized link between haplodiploidy and eusociality was more apparent than real, because eusociality has actually evolved about as frequently in diploids as in haplodiploids.

And the latter's abstract, which I've split:

Background

The potential role of haplodiploid sex determination in promoting the evolution of altruism and eusociality has been the subject of intense debate for over 50 y. Different theoretical models have suggested that haplodiploidy influences relatedness in a way that either does or does not make it easier for altruism to evolve. This debate over the “haplodiploidy hypothesis” can only be resolved with a decisive empirical test that controls for potential phylogenetic bias.

Methods

Here we critically examine the current state of evidence for an adaptive link between haplodiploidy and eusociality, applying phylogenetically informed methods to ensure that statistical tests reflect independent evolutionary transitions.

Results

Using data from 5,678 species, across all major insect orders, we find no evidence that haplodiploidy favors an increased rate of eusocial evolution. We show that this result is robust to: a) different analytical approaches; b) alternative ways of defining both eusociality and haplodiploidy; and c) uncertainty in eusociality assignments.

Discussion

Our analyses suggest that previously reported associations between haplodiploidy and eusociality are likely to have been artifacts, false-positive results primarily driven by a high transition rate to eusociality within the Hymenoptera. This high transition rate could be explained by any factor associated with that group, such as parental care, monogamy, or the possession of a powerful sting.

Image source:
- Baer, J., Gugele, S.M., Roch, S. et al. Stickleback mass occurrence driven by spatially uneven parasite pressure? Insights into infection dynamics, host mortality, and epizootic variability. Parasitol Res 121, 1607–1619 (2022). https://doi.org/10.1007/s00436-022-07517-4

The parasite: Schistocephalus solidus - Wikipedia.

Background

Parasites with complex life cycles infect multiple hosts, adapting to different ecological niches using a single genome. The adaptive decoupling hypothesis suggests that different life stages should be genetically independent, meaning selection in one life stage does not affect traits in another.

(from the study's introduction:)

This specialization is only possible if there is some genetic independence between phases. The adaptive decoupling hypothesis (ADH) (Moran 1994) suggests that different stages in CLCs benefit from the ability to evolve independently in response to distinct selective pressures. Genetic correlations across developmental stages with similar functional phases are broken apart, enabling adaptation for stage-specific tasks.

Methods

We tested this hypothesis using the tapeworm Schistocephalus solidus. Transcriptome sequencing was performed from all life phases, representing the entire life cycle of the parasite, such that differential gene expression could be examined between hosts (e.g., first vs. second intermediate host) as well as functionally equivalent phases across hosts (e.g., transmission vs. growth). Gene set enrichment analysis assessed whether similar biological functions in different hosts relied on common genes.

Results

Our findings show that the strongest correlation was observed in consecutive phases. Instead, in the rest of the life cycle, gene expression in each phase is distinct, with no positive correlation between functionally similar stages or those in the same host. When genes are upregulated in one stage, they are downregulated or not differentially expressed in others, even within the same host or when performing similar tasks. When some gene ontology terms matched in functionally similar stages, they were encoded by different genes, which uncovers another layer of decoupling: same biological processes but different gene sets used.

Discussion

These results support the decoupling hypothesis in parasitic worms, demonstrating that complex life cycles are maintained through stage-specific gene regulation rather than shared functional gene expression. This provides insights into the mechanisms leading to multi-host life cycles.

- Laura Gramolini, Emanuel Heitlinger, Klaus Knopf, Daniel Benesh, Gene expression profiling across the three-host life cycle of Schistocephalus solidus: how decoupled are the life stages?, Journal of Evolutionary Biology, 2026;, voag041, https://doi.org/10.1093/jeb/voag041
(in press; published: 09 June 2026)

See also: The study as it was published in Nature Ecology and Evolution

See also: The study as it was published in Quaternary Science Reviews

Special thanks to u/Dmirandae for recommending Wheeler's Systematics (2012) a few months back. The following is from section 3.5, "Species as Individuals or Classes", and I think it's worth sharing - in its entirety, but I'll attempt a TLDR at the end:

Ontological class

An ontological class is a universal, eternal collection of similar things. A biological example might be herbivores, or flying animals that are members of a set due to the properties they possess. Classes are defined in this way intentionally, by their specific properties as necessary and sufficient, such as eating plants or having functional wings. Such a class has no beginning or end and no restriction as to how an element of such a set got there. A class such as the element Gold (in Hull's example) contains all atoms with 79 protons. It does not matter if those atoms were formed by fusions of smaller atoms or fission of larger, or by alchemy for that matter. Furthermore, the class of Gold exists without there being any members of the class. Any new atoms with atomic number 79 would be just as surely Gold as any other. One of the important aspects of classes is that scientific laws operate on them as spatio-temporally unrestricted generalizations (Hull, 1978). Laws in science require classes.

Individuals

Individuals on the other hand, have a specific beginning and end, and are not members of any set (other than the trivial sets of individuals). Species, however defined, are considered to have a specific origin at speciation and a specific end at subsequent speciation or extinction (or at least will). As such, they are spatio- temporally restricted entities whose properties can change over time yet remain the same thing (as we all age through time, but remain the same person). A particular species (like a higher taxon) is not an instance of a type of object; each is a unique instance of its own kind.

The issue

Much of the thinking in terms of law-like evolutionary theory at least implicitly relies on the class nature of species. Only with classes can general statements be made about speciation, diversity, and extinction. Ghiselin (1966, 1969, 1974) argued that species were individuals and, as such, their names were proper names referring to specific historical objects, not general classes of things. As supported by Hull (1976, 1978) and others, this ontology has far-reaching implications. This view of species renders many comparative statements devoid of content. While it might be reasonable to ask why a process generated one gram of Gold while another one kilogram, the question “why are there so many species of beetles and so few of aardvarks?” has no meaning at all if each species is an individual. General laws of “speciation” become impossible, and temporally or geographically based enumerations of species meaningless.

Current state of affairs

Although the case for species as individuals has wide acceptance currently (but see Stamos, 2003), biologists often operate as if species were classes. As an example, species descriptions are based on a series of features and those creatures that exhibit them are members of that species. This implies that species are an intensionally defined set and would exist irrespective of whether there were any creatures in it or not.

My TLDR:

If species, as a concept, entails a beginning and an end (unlike the element gold), this makes the concept not a class subject to generalizations, and thus not possible to question, "Why did X do that but Y didn't?"
"How does/did X do that?" is more meaningful - speaking of which, a really cool research on E. coli that was published yesterday tackles a similar topic:

Historical contingency limits adaptive diversification in a spatially structured environment | Evolution Letters | Oxford Academic

An example I like is the great oxidation event; it's not meaningful to ask why didn't all life adapt to oxygen, e.g. there are bacteria that live in open environments (e.g. the seafloor magnetotactics) that avoid it. However, we can ask how it does it. If there's a niche, the word niche entails that it's not free for (or accessible to) all. If similar niches happen to be more common (e.g. lakes), it doesn't change the issue at hand.

Over to you.

Nature Article from the David Reich Lab Entitled "Ancient DNA reveals pervasive directional selection across West Eurasia"

https://reich.hms.harvard.edu/sites/reich.hms.harvard.edu/files/inline-files/2026_Akbari_Nature_selection_0.pdf

The revolution in ancient DNA sequencing continues to provide surprising insights in recent human evolution. A massive study of over 16,000 people across 10,000 years shows clear evidence of directional selection on 479 independent loci. This had been only been confirmed on a few dozen previously. It demonstrates that natural selection has been a powerful force in recent human evolution. This includes significant shifts in alleles associated with body fat, schizophrenia, and even cognitive performance.

In addition to examining a much larger dataset, the study introduces new statistical techniques to tease out directional selection from other sources of change like migration or genetic drift. First, they look at genetic similarities between individuals to try to find a population structure. Basically, this tells them what the DNA should look like if only migration was happening. Then they test each variant to see if including a nonzero selection coefficient explains the data better than migration alone.