Landmark Experiments in Biology
Twenty-nine classic papers. Four threads through modern biology.
A physicist’s reading list of classic biology. The selection is deliberately incomplete. Each entry gives the original paper, the central idea, and the observation or argument that made it decisive.
For current work on molecular machines, biological information, and living matter, see Research and What Is Life?.
Evolution
Selection, heredity, origins, and evolution made experimental.
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Darwin C, Wallace A — On the tendencies of species to form varieties; and on the perpetuation of varieties and species by means of selection · J Proc Linnean Soc Zool 3, 45–62 (1858).Natural selection
Variation, inheritance, and differential survival became a mechanism for adaptation without a designer.
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Mendelian inheritance
Counting offspring exposed discrete hereditary factors beneath the continuous appearance of organisms.
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Miller SL — Production of Amino Acids Under Possible Primitive Earth Conditions · Science 117, 528 (1953).Prebiotic chemistry
The origin of life became an experimental chemistry problem: simple gases and energy produced amino acids.
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Eigen M — Self-organization of matter and the evolution of biological macromolecules · Naturwissenschaften 58, 465–523 (1971).Molecular evolution
Replication error became a quantitative limit on how much genetic information an evolving molecular population can preserve.
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Kimura M — Evolutionary rate at the molecular level · Nature 217, 624–626 (1968).Neutral evolution
Molecular evolution could proceed rapidly even when many substitutions were selectively neutral.
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Mills DR, Peterson RL, Spiegelman S — An Extracellular Darwinian Experiment with a Self-Duplicating Nucleic Acid Molecule · Proc Natl Acad Sci USA 58, 217–224 (1967).Experimental evolution
RNA replicated and evolved in a test tube, reducing Darwinian evolution to a stark molecular experiment.
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Dubertret B, Liu S, Ouyang Q, Libchaber A — Dynamics of DNA-Protein Interaction Deduced from in vitro DNA Evolution · Phys Rev Lett 86, 6022–6025 (2001).DNA–protein evolution
Evolution in vitro became a probe of the physical interaction between a DNA sequence and its binding protein.
Development
How form emerges: morphogenesis, lineage, patterning, and induction.
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Turing A — The chemical basis of morphogenesis · Phil Trans R Soc Lond B 237, 37–72 (1952).Morphogenesis
Diffusion, normally a smoothing process, was shown to create spatial pattern when coupled to reaction.
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Brenner S — The genetics of Caenorhabditis elegans · Genetics 77, 71–94 (1974).Genetic model organism
A transparent animal with a small nervous system became a tractable object for connecting genes to development and behavior.
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Sulston JE, Horvitz HR — Post-embryonic Cell Lineages of the Nematode, Caenorhabditis elegans · Developmental Biology 56, 110–156 (1977).Cell lineage
The history of every cell could be followed: development became a reproducible branching genealogy.
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Lewis EB — A gene complex controlling segmentation in Drosophila · Nature 276, 565–570 (1978).Homeotic genes
Genes were shown to specify positional identity along the body, revealing a genetic logic of anatomical form.
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Nüsslein-Volhard C, Wieschaus E — Mutations affecting segment number and polarity in Drosophila · Nature 287, 795–801 (1980).Segmentation
A systematic mutant screen uncovered the hierarchy of genes that divides an embryo into an ordered body plan.
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Spemann H, Mangold H — Induction of Embryonic Primordia by Implantation of Organizers from a Different Species · Arch Mikroskop Anat Entwicklungsmechanik 100, 599–638 (1924).Embryonic induction
A transplanted patch of tissue reorganized its neighbors and induced a second body axis: development depends on instructive interactions.
Molecular Biology
From chromosomes to DNA, the genetic code, replication, and regulation.
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Sturtevant AH — The linear arrangement of six sex-linked factors in Drosophila, as shown by their mode of association · J Exp Zool 14, 43–59 (1913).Genetic mapping
Recombination frequencies became distances, turning gene order along a chromosome into a measurable map.
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Creighton HB, McClintock B — A correlation of cytological and genetical crossing-over in Zea mays · Proc Natl Acad Sci USA 17, 492–497 (1931).Crossing-over
Genetic recombination was tied directly to physical exchange between homologous chromosomes.
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Avery OT, MacLeod CM, McCarty M — Studies on the chemical nature of the substance inducing transformation of pneumococcal types · J Exp Med 79, 137–158 (1944).DNA as genetic material
Purified DNA transferred a heritable trait, identifying DNA as the transforming principle.
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Luria SE, Delbrück M — Mutations of bacteria from virus sensitivity to virus resistance · Genetics 28, 491–511 (1943).Mutation by fluctuation
The distribution of resistant colonies showed that mutations arise before selection rather than because organisms need them.
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Lederberg J, Cavalli LL, Lederberg EM — Sex compatibility in Escherichia coli · Genetics 37, 720–730 (1952).Bacterial genetics
Genetic recombination in bacteria established that bacterial heredity need not be purely clonal.
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Pauling L, Corey RB, Branson HR — The structure of proteins: two hydrogen-bonded helical configurations of the polypeptide chain · Proc Natl Acad Sci USA 37, 205–211 (1951).Protein structure
Chemical geometry and hydrogen bonding predicted the alpha helix before a complete protein structure was known.
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Watson JD, Crick FHC — Molecular structure of nucleic acids · Nature 171, 737–738 (1953).DNA structure
Complementary base pairing made molecular structure itself suggest a mechanism for copying genetic information.
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Matthaei JH, Nirenberg MW — Characteristics and stabilization of DNAase-sensitive protein synthesis in E. coli extracts · Proc Natl Acad Sci USA 47, 1580–1588 (1961).Genetic code
A synthetic RNA of one repeated letter produced one repeated amino acid, opening the dictionary between nucleic acids and proteins.
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Meselson M, Stahl FW — The replication of DNA in E. coli · Proc Natl Acad Sci USA 44, 671–682 (1958).DNA replication
Density labeling turned alternative replication mechanisms into visibly different bands and selected semiconservative copying.
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Crick FHC, Barnett L, Brenner S, Watts-Tobin RJ — The general nature of the genetic code for proteins · Nature 192, 1227–1232 (1961).Triplet code
Frameshift mutations revealed that genetic information is read in non-overlapping groups of three bases.
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Jacob F, Monod J — Genetic regulatory mechanisms in the synthesis of proteins · J Mol Biol 3, 318–356 (1961).Gene regulation
The operon linked regulatory genes and DNA control sites to the conditional expression of proteins.
Neurobiology
Synapses, receptive fields, ion channels, excitability, and memory.
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Katz B, Miledi R — The statistical nature of the acetylcholine potential and its molecular components · J Physiology 224, 665–699 (1972).Quantal transmission
Synaptic release was resolved into discrete molecular packets, linking stochastic microscopic events to neural signals.
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Hubel DH, Wiesel TN — Receptive fields of single neurones in the cat's striate cortex · J Physiol 148, 574–591 (1959).Visual cortex
Single cortical neurons responded selectively to oriented edges at particular positions in the visual field.
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Neher E, Sakmann B — Single-channel currents recorded from membrane of denervated frog muscle fibres · Nature 260, 799–802 (1976).Single ion channels
Electrical current through a single membrane channel became directly observable rather than an inferred average.
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Hodgkin AL, Huxley AF — A quantitative description of membrane current and its application to conduction and excitation in nerve · J Physiology 117, 500–544 (1952).Action potential
Voltage-clamp measurements and a quantitative model explained the action potential through voltage-dependent sodium and potassium conductances.
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Kandel ER, Tauc L — Heterosynaptic facilitation in neurones of the abdominal ganglion of Aplysia depilans · J Physiol 181, 1–27 (1965).Synaptic plasticity
Pairing inputs changed synaptic efficacy in identified Aplysia neurons, making plasticity accessible at the level of single cells and synapses.
Course presentations
Citation · Elisha Moses & Tsvi Tlusty, Landmark Experiments in Biology, adaptivelivingmatter.org/landmark.html .