The 7 Best Things I Learned in 2025

2025 brought us many advances, and some new findings to inspire optimism.

My top 7 are pretty biology-heavy, both because there were many breakthroughs, and because I fell in love with the field this year.1

Here they are, in no particular order:

Few questions are as significant as whether life exists outside of Earth. 2025 started off strong with an announcement in January that every nucleotide (letter) of DNA and RNA was found on samples retrieved from the asteroid Bennu. They also found 14 of the 20 amino acids that we use to create proteins. This, and other findings, make it seem like the building blocks of life are plentiful in outer space. If life is rare, it probably isn’t because space lacks the right ingredients.

Then, NASA announced that the best explanation they have to explain these circles of iron on the Martian “Cheyava Falls” rock is previous microbial life. WHAT!?

It’s possible they’re wrong, but the current best explanation for these geological formations is the metabolisms of microbes converting rust to iron phosphate and iron sulfide via redox reactions.

In another year, this may have been the biggest story of all, not just in science. Someone famous getting shot on the same day as the NASA announcement had a bit of a chilling effect on the news.

2025 marked the first year that a human baby was saved because of our ability to edit the genome in multiple body cells. There have been other gene editing successes, but they can’t claim this title because the disease wouldn’t have been fatal.

The treatment edited a single nucleotide (DNA letter) in many of the baby’s liver cells, successfully restoring his ability to produce an enzyme (CSP1) that breaks down protein, and prevents ammonia from accumulating in his blood.

Energy transitions are slow, so the rough shape of an economy’s emissions in the near-term isn’t too difficult to forecast. However, China’s emissions peaking in 2025 is roughly the earliest estimate that climate scientists had just 10 years ago.2

Emitting over 30% of all emissions, China is a bit of a paradox. They export 70-80% of clean energy tech, yet continue to use coal for ~60% of their own electricity, though this is decreasing. Picture The Great Pyramid of Giza made of coal, and then over 1,000 more lined up behind it. That’s how much coal China uses in a year, and yet China has done more for the global shift towards renewables than any other country.

China has a vested interest in continuing to lead on climate. Solar panels and wind turbines are lucrative export markets for them, and they could be uniquely hurt by climate change due to its impact on rice farming (though another discovery this year could offset this impact).

They have a running history of beating their climate goals and deadlines. For the planet’s sake, I hope they continue to do so, while supplying the world with the cheapest clean energy tech available.

Scientists have searched for decades for a treatment for Hungtington’s disease, and came up empty-handed. This year, results of a novel therapy that was injected into the brains of 12 people slowed symptom progression by 75%!

Huntington’s disease results from a mutation in the HTT gene that produces the Huntingtin protein.

This gene therapy is seriously cool - it uses a virus that’s been emptied of its DNA to deliver a DNA loop into neurons. This sequence isn’t actually edited into the genome, but rather sits inside the nucleus, next to the existing DNA.

The new DNA encodes for something that binds to the bad mRNA sequence from the existing bad HTT gene, and prevents the bad mRNA sequence from constructing the malformed protein. Since adult neurons don’t divide and reproduce, this separate loop of DNA doesn’t get diluted down, offering long-term protection against malformed Huntingtin proteins despite it being a one-time shot.

We’re getting good at the RNA-side of biological engineering, which is neat since it means we can deliver medicines that act like a gene therapy would, without actually needing to gene edit! A rough analogy is that we can change the factory’s instruction manual without having to alter the machines.

This year, I feel like we got a glimpse into the future with two new blood tests.

One test came out that had a greater than 90% chance of correctly predicting Alzheimers, though it is only effective in patients which already showed a sign of cognitive decline. Nonetheless, it is evidence that blood tests have the potential to warn of Alzheimer’s earlier and less invasively than existing methods. More details here:

And there was an even more promising result for cancer! GRAIL’s Galleri test caught 7x the number of cancers in 25,000 people when paired with existing screening methods (mammograms, colonoscopies, and pap smears) compared to just existing screening methods alone. This fell to 3x when patients also underwent prostate exams, but a 300% increase is still wild!

Its false-positive rate isn’t perfect, and it still can’t detect 100% of cancers early, but existing methods can’t either! More details here:

Sidenote: There’s a heuristic in journalism called “Betteridge’s Law of Headlines”, which states "Any headline that ends in a question mark can be answered by the word no." The above is an exception.

These tests aren’t yet good enough for national-adoption at annual checkups, but they show the path forward is promising. I’d wager it’s not just promising, it’s inevitable, and will arrive in the next decade.

This finding still blows my mind. A new word was invented to describe it: xenoparity.

Scientists in France realized that M. Ibericus ant queens could give birth to male clones of another ant species - M. Structor - that they rely on to create hybrid worker ants, allowing them to colonize regions that don’t have existing M. Structor populations. That is straight out of sci-fi!!

I covered more details here:

The impact of GLP-1s is difficult to overstate. However, since most people that use them also lose a lot of muscle mass, there’s a big profit incentive for pharma to create drugs that prevent muscle-loss. Existing anabolic steroids have a ton of downsides, so something more gentle is needed that adds or preserves muscle without being a global androgen receptor agonist, as anabolic steroids are.

A new class of drugs is showing real promise, called myostatin-inhibitors. Myostatin prevents the growth of new muscle, and in large amounts, breaks down existing muscle. Inhibiting it results in more muscle mass. Of course, none of these drugs are approved yet, so this still has time to crash and burn if unforeseen side effects pop up as it’s tested in a more diverse group of patients. But early results are promising - in an earlier trial, one drug had patients lose weight and gain muscle at the same time. Bonkers.

We’ll have a better idea in April 2026 when early results from a phase 2 combo trial with tirzepatide are announced. More details here:

Thanks for a great year! After 100 newsletters released every Sunday, I trailed off in December for some R&R. In 2026, the release cadence will be more erratic as I work hard to bring you more video essays and interviews with experts.

The 7 above are my favorites, but so much more happened!

• We may have found a way to reverse some of the effects aging has on the immune-system

• The Clinton Health Access Initiative (CHAI) arranged a deal to provide Lenacapavir, the first 100% effective HIV prevention medication to low-income nations for $40

• Researchers discovered a naturally occurring gene variant that protects rice from heat waves

• Colossal Biosciences edited woolly mammoth genes into mice

• The largest mosquito factory opened in Brazil to combat Dengue and other arboviruses

• Two more antibiotics were approved to treat gonorrhea, which is particularly good at developing resistance to existing ones

As always, restacking and sharing this newsletter is the best way to support me, and help imperfect, but improving! grow.

Edited by my wife Minttu!