They tagged DNA with phosphorus-32 and protein with sulfur-35, then ripped phage shells off bacteria with a blender.
2:16
Where the labels landed
80% of phosphorus-32 entered bacteria; all sulfur-35 stayed outside — proving DNA crosses the membrane, protein does not.
3:14
What got passed on
Progeny phages carried phosphorus-32 but not sulfur-35 — showing only DNA is inherited.
4:05
The conclusion
They concluded DNA, not protein, is the genetic material — the first direct experimental evidence for that claim.
5:38
The enzyme control
Intact phages resisted DNase — confirming the 32P signal came from protected, functional DNA, not debris.
Worth your time?
Yes. Study the whole thing.
4.5/ 5
What works
It confirmed DNA is genetic material.
It showed DNA enters bacterial cells while most protein does not.
It demonstrated inheritance of DNA — not protein — in progeny.
It concluded DNA, not protein, is the genetic material.
What does not
It does not show how DNA encodes information.
It does not rule out all non-protein genetic roles for other molecules.
It does not address RNA, epigenetics, or horizontal gene transfer.
Study it if
biologists
students of molecular history
anyone who thinks 'DNA is genetic material' is just textbook dogma
Skip it if
those seeking mechanism, structure, or clinical application
The written brief1 min read
What the work claims
DNA, not protein, is the genetic material. This claim rests on differential entry and inheritance of radioactively labelled molecules during phage infection.
How it was done
Hershey and Chase used radioactive phosphorus-32 to label DNA and sulfur-35 to label protein in T2 bacteriophages. They infected bacteria, then separated phage coats from cells using a blender and centrifugation.
What holds up
The core result holds: most 32P entered bacteria and appeared in progeny; nearly all 35S stayed outside. The method isolated physical location and inheritance of labels. The conclusion — DNA, not protein, is the genetic material — follows directly from these observations.
What does not
It does not show how DNA encodes information, replicates, or mutates. It does not rule out all non-protein genetic roles for other molecules. It does not address RNA, epigenetics, or horizontal gene transfer.
Why it matters beyond the lab
It ended the protein-as-genetic-material consensus. It redirected molecular biology toward nucleic acids — enabling sequencing, recombinant DNA, and modern genetics. It established that heredity is a chemical process traceable by atomic labelling.
Is it worth your time
Yes. It is the cleanest experimental demonstration that DNA carries hereditary information — not as inference or correlation, but via direct tracking of labelled molecules across infection and replication.