2022 Nobel Prize in Physiology or Medicine
Reason for Award
for his discoveries concerning the genomes of extinct hominins and human evolution
Laureates
Sweden
Explanation
This prize is about reading very old DNA, the instruction book of life, from ancient bones to learn secrets about our distant relatives. DNA breaks over time, just like a letter’s ink that smears in the rain. Svante Pääbo invented careful ways to collect and read these broken pieces. He managed to read the DNA of Neanderthals and Denisovans—people who no longer live today. He also discovered that a small part of their DNA is mixed into modern humans. That means all of us are still connected to those ancient people like a giant family.
Related Keywords
Neanderthals
An extinct Homo lineage that inhabited Eurasia ~400,000–30,000 years ago. They had robust skeletons and brain volumes comparable to or slightly larger than modern humans. Pääbo’s genomic work showed that present-day humans share 1–2% of their DNA with Neanderthals. Genomes reveal small effective population sizes and signs of inbreeding bottlenecks. Several Neanderthal alleles related to immunity and skin biology were retained in modern humans due to adaptive advantage.
Denisovans
An unknown hominin first identified in 2008 from a finger bone in Siberia’s Denisova Cave. Sparse morphology but genomic data place them as a sister clade to Neanderthals, diverging ~400 kya. Melanesians and some Asian high-altitude groups inherit 4–6% Denisovan DNA; the EPAS1 gene variant aids hypoxia adaptation. Evidence suggests a geographic range from Southeast Asia to Oceania. Discovery of a first-generation Neanderthal–Denisovan hybrid confirmed interbreeding between the two archaic groups.
ancient DNA
DNA recovered from biological remains that are hundreds to tens of thousands of years old. It is highly fragmented and chemically modified by deamination and oxidation, typically 30–100 bp long. Distinguishing endogenous molecules from contamination and modelling damage patterns are critical for analysis. Innovations such as silica-binding extraction, single-stranded libraries, and UDG treatment have broadened its study. Ancient DNA now informs palaeontology, archaeology, and pathogen evolution.
introgression
The permanent incorporation of genetic material from one species or subspecies into another via hybrid offspring. In humans, 1–6% of the genome originates from Neanderthals or Denisovans. Beneficial alleles can rise in frequency by positive selection, whereas deleterious ones are purged, creating genomic ‘hotspots’ and ‘deserts’. These patterns inform adaptation and reproductive isolation dynamics. Introgression is detected with statistics such as D- or f4-tests and followed by functional assays to assess phenotypic impact.
next-generation sequencing
A collection of technologies that read DNA sequences far faster and cheaper than Sanger sequencing. For ancient DNA, it captures billions of short (<100 bp) reads in parallel. Shotgun data allow statistical assessment of contamination sources and damage patterns. Adapter tagging and barcoding let multiple samples run simultaneously and enable error correction. Pääbo’s work leveraged 454, Illumina, and single-stranded library methods to unlock archaic genomes.
human evolution
The process by which Homo sapiens, originating in Africa, dispersed ~70,000 years ago and adapted to diverse environments. Fossil and lithic studies now integrate genomic data, enabling high-resolution reconstruction of lineages, admixture, and population size changes. Interbreeding with Neanderthals and Denisovans provided genetic diversity and adaptive alleles. Catalogues of human-specific mutations offer clues to what makes us uniquely human. Climate shifts, cultural innovations, and pathogen pressures jointly shaped evolutionary trajectories.