Kellis, Manolis

professor at MIT, head of the MIT Computational Biology Group; his second appearance on the podcast

Manolis Kellis: Origin of Life, Humans, Ideas, Suffering, and Happiness

Lex Fridman Podcast · Sep 12, 2020

• Manolis Kellis
• epigenome
• origin of life
• RNA world
• natural selection
• extraterrestrial life
• meaning of life
• suffering
• Greek philosophy
• MIT

Core ideas

Kellis opens with the engineering marvel of the human epigenome — two meters of DNA per cell compacted a millionfold, with the "epigenome" (chemical modifications like methylation, layered on top of the DNA "score") acting like a conductor that lets each cell's identical genome play only the "sheet music" relevant to its role, coordinating thousands of genes per cell out of ~20,000 total. He extends this into a discussion of multi-level natural selection — nucleotide, gene, gene-regulatory-element, cell, tissue, organism, and ultimately ecosystem — arguing altruism and inter-species symbiosis emerge because nakedly hostile organisms and ecosystems tend not to survive, and that gene "context" matters as much as gene identity (illustrated by incompatibilities between Neanderthal gene variants and the modern human genome that were harmless in their original genetic context). Asked what drove Neanderthal extinction, Kellis suggests human tribalism and a instinctive drive to eliminate anything "almost human" but not quite, while noting extensive interbreeding occurred alongside the conflict — and laments that of many parallel hominid and animal lineages, only the "boring" tetrapod body plan survived to dominate, calling underwater invertebrate life staggeringly more diverse by comparison.

A long section addresses the origin and definition of life, organized around three necessary ingredients: metabolism (taking in energy/nutrients and making them "self"), compartmentalization (a lipid-bilayer boundary establishing self vs. non-self, without which there's no unit for selection to act on), and replication (not necessarily self-replication — any reinforcing cycle, like A helps make B helps make C helps make A, suffices to ignite evolution). He walks through the sequence of an "RNA world" preceding DNA and protein — RNA self-folding into functional 3D shapes, self-replicating enzymatically, then delegating information storage to the more stable double-stranded DNA and most actuation to the more versatile 20-amino-acid protein toolkit — calling the ribosome (RNA that translates RNA into protein) one of life's greatest inventions, understood as the survivor of many competing "software infrastructures" for self-preservation. He argues abiogenesis is probably inevitable wherever the ingredients exist (citing Europa's ice-shielded, tidally-heated ocean as a plausible independent site) and prefers hydrothermal deep-ocean origins over "seeded from space" (which just relocates the same unanswered question) or surface origins (given how comparatively harsh, low-diversity life above the waterline is). Given the likely biochemical strangeness of alien life, he predicts contact would probably be safe rather than mutually infectious, since organisms evolved for wildly different chemistries and energy sources likely couldn't metabolize or attack each other at all — and that detecting alien life wouldn't require DNA sequencers, since life's key signature is that it visibly "fights against" and locally reverses simple physical entropy/diffusion, creating chemical patterns no random reaction would produce.

Kellis frames a philosophical arc of "transformations" running from bare biological life (Alexander the Great's "to zên," mere living) toward a fuller, examined human life ("to eu zên," living well) — eukaryotic compartmentalization, germline specialization in multicellular animals (where, bluntly, "the rest of your body" exists only to get the germline to the next generation), the emergence of centralized nervous systems as decision-making "operating systems" running on a slower genetic-expression timescale beneath fast millisecond behavior, and finally the human brain's capacity to override evolutionary programming entirely (choosing not to reproduce, eat, or survive). He connects this arc to his own "meaning of life" symposium, sparked by turning 42 and recognizing he'd completed the academic "rat race" (a metaphor borrowed from his mentor Christos Papadimitriou) only to realize there is no finish line — proposing instead a "path, not destination" view of life (via Cavafy's poem "Ithaka") and an "all-inclusive resort" reframe in which he treats his demanding professional obligations as activities he'd choose even if wealth removed all necessity.

On suffering, Kellis argues modern culture — via relentlessly happy-ending media — leaves people unprepared to cope with life's inevitable hardship, contrasting this with the deliberately devastating Greek folk songs and children's stories he grew up with (a woman ordered by the Virgin Mary to choose which soldier dies instead of her brother; two children who die at the end of a four-page bedtime story), which he says exist to expand emotional range and calibrate gratitude rather than glorify misery. He resists framing gratitude as comparative ("better than the Joneses"), instead describing how children in war zones and his own young daughter (recovering cheerfully from a serious burn) demonstrate a capacity to simply accept present circumstances and still find real joy — concluding that the goal of life isn't happiness but fulfillment through struggle, and that detaching self-worth from others' opinions (a lesson he learned by realizing colleagues judged him only by his visible achievements, not his private awareness of his own flaws) frees a person from needing validation or status. He describes his own path — moving countries and schools almost yearly from ages 11 to 19 — as an accidental but valuable mechanism for repeated self-reinvention, and closes with two poems he wrote as a teenager (on lost love and impending high-school graduation), using them to illustrate his etymological point that "passion" derives from the Greek word for suffering — meaning love is inseparable from willingly accepting emotional vulnerability ("birds who love are birds who cry").

Excerpts