Lesson 9 — What Comes Next?
What Is Evolution Really?
Learning Material
1 pagesLesson 9 — What Comes Next?
Understanding the Complex: What Is Evolution Really?
In 2010, Svante Pääbo's team sequenced the Neanderthal genome. In 2012, they sequenced the Denisovan genome from a fragment of finger bone — and identified an entirely new human relative nobody had known existed. By 2022, they had sequenced genomes from dozens of ancient humans, pushing back further and further into the past.
The pace of paleogenomics has been extraordinary — partly because the technology is improving rapidly, and partly because the questions it can answer keep expanding. We can now recover meaningful genetic information from bones 400,000 years old. We can sequence not just human remains, but ancient plant DNA, animal DNA, even environmental DNA extracted from permafrost — traces of organisms that lived and died without leaving anything so intact as a bone.
Where does this go?
Deeper into the human past
The most obvious frontier is recovering older and older genomes. The practical limit for ancient DNA recovery is around one to two million years — beyond that, the DNA degrades beyond recovery, even in cold conditions. That still covers most of the genus Homo: we can recover DNA from Homo heidelbergensis, from Homo naledi, potentially from Homo erectus.
What those genomes will show is unclear. But they'll fill in a human family tree that is far more branched and interconnected than we thought twenty years ago. Recent work has already suggested that multiple archaic populations interbred with early modern humans at different points — Neanderthals in Europe and western Asia, Denisovans in Southeast Asia and the Pacific, and possibly other populations we haven't identified yet. Those encounters left traces in the genomes of living people that affect health, immunity, and disease risk today.
Understanding that history isn't just academic. The Neanderthal-derived alleles associated with increased COVID-19 severity were identified because we had the ancient genome to compare against. As we identify more archaic-derived alleles, we'll be better positioned to understand why different populations have different disease susceptibilities.
Directed evolution at scale
Frances Arnold's directed evolution — using artificial selection to evolve proteins in the lab — is already transforming biotechnology. The next frontier is extending the process to whole genomes, and to systems more complex than individual proteins.
The possibility is directed evolution of microorganisms toward specific capabilities: bacteria that can degrade specific pollutants, yeast engineered to produce specific pharmaceuticals, photosynthetic microbes optimized to capture carbon more efficiently. Unlike traditional genetic engineering, which inserts specific modifications, directed evolution uses evolutionary search itself to find configurations that work — often producing molecules and systems more sophisticated than any a human designer could specify.
The intersection with synthetic biology is rich. Synthetic biologists build new biological systems from characterized parts; evolutionary biologists understand how to use selection to improve them. Together, these fields are beginning to produce organisms that never existed in nature, shaped by evolutionary processes but steered by human goals.
Evolution and extraterrestrial life
If we find life elsewhere in the solar system — in the oceans beneath the ice of Europa or Enceladus, in the Martian subsurface — the question of whether it evolved by Darwinian mechanisms will be immediate.
The argument that it likely would: natural selection is not a biological process; it's a logical consequence of any system with heritable variation and differential reproduction. If life exists in another environment, it presumably exists there because it survived and reproduced — which means selection has been acting. The specific mechanisms of inheritance might be different (not necessarily DNA-based), but the logic of evolution would apply.
If we found life with different biochemistry, operating by evolutionary principles but through a different molecular implementation, it would be the most profound scientific discovery in human history — because it would establish that evolution is not just a fact about life on Earth, but a universal feature of any living system anywhere.
Gene drives: intentional evolution
Perhaps the most consequential near-term application of evolutionary thinking is the development of gene drives — genetic elements that spread through wild populations faster than Mendelian inheritance would predict.
Malaria kills around 600,000 people per year, almost all children under five in sub-Saharan Africa. The disease is transmitted by Anopheles mosquitoes. A gene drive could, in principle, suppress or eliminate Anopheles populations in specific regions, eliminating malaria transmission there.
This is being actively developed. Field trials are being planned. The ethical and governance challenges are significant: who consents on behalf of an ecosystem? What if the drive spreads beyond the target region? What are the ecological consequences of eliminating a mosquito species? These are being worked through in real time, with researchers, ethicists, regulatory bodies, and affected communities in conversation.
The point is that evolution is no longer something that only happens to us. We are beginning, with CRISPR gene drives and synthetic biology, to be actors in the evolutionary process — not just organisms that result from evolution, but agents who can influence where it goes.
Next lesson: What if — three evolutionary thought experiments that push the boundaries of what we know.
Reading time: approx. 9–10 minutes