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A brief history of modern biology


last_modification Published: Jan 9, 2024
last_modification Last Updated: Jan 9, 2024

Charles Darwin

.center[The fabric of biology: 1809 - 1882]


Provisional theory of pangenesis. All sperm, egg, buds consisted of multitude of gemmules given off by “ each separate atom of the organism ”.

Francis Galton

.center[Experimental validation: 1822 - 1911]


Blood transfusion in rabbits produces no evidence to support provisional theory of pangenesis.

Darwin gets pissed

Darwin letter to Nature

Gregor Johann Mendel

.center[Quantifiable heredity: 1822 - 1884]

.pull-left[ Mendel ]


Mendel gets lucky

Mendel results

.footnote[(From Magner 2002)]

Mendel cartoon

.footnote[(From Gonick Wheelis 1991)]

Perhaps too lucky

Mendel re-examination

.footnote[(From Sturtevant 2001)]


.center[The Rediscovery]


Meanwhile chromosomal theory evolves



The fly room




Academic competition!

Muller Scribble

.footnote[(From Carson 2004)]

But what is the carrier of information?

The Church of Phage

Delbrück, Luria, Hershey


NP 1969: “ discoveries concerning the replication mechanism and genetic structure of viruses

Luria Delbrück Experiment

Fluctuation test

Hershey-Chase experiment

.pull-left[ Hershey and Chase ]

.pull-right[ Hershey-Chase experiment ]

Lederberg-Tatum experiment

Genetic recombination in E. coli

Lederberg-Tatum Experiment

Blender again!

Genetic distance in bacteria


Crick, Franklin, Watson, Wilkins

DNA is an antiparallel double helix

Crick, Franklin, Watson, Wilkins

Three papers

Meselson, Stahl

DNA replication is semiconservative

Meselson, Stahl

Meselson-Stahl experiment

CsCl gradient centrifugation

Meselson, Stahl experiment 1

Meselson, Stahl experiment 2

Gene function

Lwoff, Jacob, Monod

Lysogeny, prophage, genetic maps, gene regulation

Lwoff, Jacob, Monod


Reverse Transcription, Recombinant Age

Berg experiment

Berg experiment


.pull-left[ PCR1 ]

.pull-right[ PCR2 ]

DNA Sequencing is here!

Wu, Sanger, Gilbert, Mullis

Thank you!

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