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50 free Hard DNA trivia questions with answers — science & nature quiz, new questions added Aug 2026.
These hard DNA trivia questions are for people who already know that A pairs with T and want to be tested on the rest: the experiments that proved DNA is the genetic material (Avery-MacLeod-McCarty, Hershey-Chase, Meselson-Stahl), the people behind the double helix (Miescher, Chargaff, Franklin, Gosling, Wilkins, Pauling's wrong triple helix), and the code-breakers who worked out how three letters become one amino acid. They also cover replication machinery (polymerases, Okazaki fragments, telomeres), mitochondrial DNA, ancient DNA and the Neanderthal genome, DNA fingerprinting and its first conviction, PCR, Sanger and next-generation sequencing, the Human Genome Project versus Celera, recombinant DNA and CRISPR. The easiest questions here would be the hardest on a general science quiz. The hard ones want the isotope Meselson and Stahl used, the year the true human chromosome count was fixed, the amino acid encoded by poly-U and the base-pair count of the mitochondrial genome. For a warm-up, start with our main DNA trivia (brainpickle.app/quiz/a/dna); the kids version is at brainpickle.app/quiz/a/dna-for-kids. Every answer has been checked against a reference encyclopaedia, and each question shows its explanation and citation once you have answered.
30 of 50 questions with answers and explanations. Play the quiz
Q 01In whose laboratory at the University of Tubingen did Friedrich Miescher isolate 'nuclein' in 1869?
Felix Hoppe-Seyler
Miescher got his white blood cells from pus on surgical bandages collected at a nearby hospital.
Q 02The 1944 Avery-MacLeod-McCarty experiment showed DNA was the 'transforming principle' in which bacterium?
Pneumococcus
At the time most biologists assumed proteins carried heredity, which is what the very word 'protein' had implied.
Q 03The 1952 Hershey-Chase 'blender experiment' used what kind of virus to show DNA, not protein, enters the host?
Bacteriophage
Phage DNA entered the bacteria while most of the protein coat stayed outside and was knocked off in a blender.
Q 04Chargaff's rules state that in DNA adenine equals thymine and guanine equals what?
Cytosine
Erwin Chargaff's ratios were a crucial clue that led Watson and Crick to complementary base pairing.
Q 05Meselson and Stahl's 1958 experiment labelled DNA with a heavy isotope of which element?
Nitrogen
Nitrogen is in every DNA base, so 15N-labelled parent strands could be separated from lighter new ones by density.
Q 06Who actually took Photo 51, the X-ray diffraction image of DNA, at King's College London in 1952?
Raymond Gosling
He was Franklin's PhD student, and it was the 51st diffraction photograph he had taken; Wilkins later showed it to Watson without permission.
Q 07After leaving King's in 1953, Rosalind Franklin did pioneering virus work at which London institution?
Birkbeck
She worked under J. D. Bernal and died of ovarian cancer at 37 the day before she was due to unveil the tobacco mosaic virus structure in Brussels.
Q 08Watson and Crick's structure paper appeared in which volume of Nature, dated 25 April 1953?
171
It occupied just pages 737-738, with supporting papers by Wilkins and by Franklin and Gosling in the same issue.
Q 09What fundamental chemical error did Linus Pauling's 1953 triple-helix DNA model make?
It had neutral phosphate groups
Neutral phosphates conflicted with the well-known acidity of DNA, and Watson and Crick published the correct double helix months later.
Q 10Which Cavendish Laboratory director first publicly announced the DNA double helix in a May 1953 talk?
Lawrence Bragg
His talk at Guy's Hospital led to a News Chronicle article titled 'Why You Are You'.
Q 11Maurice Wilkins, who shared the 1962 Nobel Prize with Watson and Crick, was born in which country?
New Zealand
He insisted Franklin's name go first when King's College named its Franklin-Wilkins Building in 2000.
Q 12Which cytogeneticist established in 1956 that humans have 46 chromosomes, not 48 as long believed?
Joe Hin Tjio
Painter had counted 24 pairs in 1923, and his error was copied for three decades.
Q 13Francis Crick first stated the 'central dogma' in a 1957 lecture; in what year was it published?
1958
It describes the flow of information from DNA to RNA to protein and why it does not run backwards into protein.
Q 21Cann and Wesley Brown found that human mitochondrial DNA mutates how much faster than nuclear DNA?
5 to 10 times
That fast, steady clock underpins the concept of Mitochondrial Eve, the matrilineal most recent common ancestor of all living humans.
Q 22Which discovery earned Phillip Sharp and Richard Roberts the 1993 Nobel Prize in Physiology or Medicine?
Split genes (introns)
Several labs found in 1977 that genes are interrupted by non-coding introns; much of the Sharp lab's work was done by postdoc Susan Berget.
Q 23Reverse transcriptase was discovered in 1970 by David Baltimore and which other scientist?
Howard Temin
Q 14The 1961 Nirenberg-Matthaei poly-U experiment produced a protein made solely of which amino acid?
Phenylalanine
It was the first codon deciphered, showing UUU codes for phenylalanine and cracking the genetic code open.
Q 15Reading three bases at a time gives how many possible codons for the 20 standard amino acids?
64
Four to the third power is 64, so most amino acids are specified by more than one codon and three are stop signals.
Q 16Arthur Kornberg discovered DNA polymerase I in E. coli in 1956 and won the Nobel Prize in which year?
1959
His son Thomas Kornberg later discovered DNA polymerase II, and Arthur's other son Roger won a chemistry Nobel in 2006.
Q 17Okazaki fragments, the short pieces of the lagging strand, are joined together by which enzyme?
DNA ligase
Reiji and Tsuneko Okazaki discovered them in the 1960s; in eukaryotes they run about 150 to 200 base pairs.
Q 18Human telomeres consist of several thousand repeats of which six-letter sequence?
TTAGGG
Blackburn, Greider and Szostak shared the 2009 Nobel Prize for discovering how telomeres and telomerase protect chromosome ends.
Q 19Which two geneticists independently proposed in 1938-39 that chromosome ends had a special structure?
Hermann Muller and Barbara McClintock
Muller worked with fruit flies and McClintock with maize; the word combines the Greek for 'end' and 'part'.
Q 20Human mitochondrial DNA contains how many base pairs?
16,569
It encodes just 13 proteins and is inherited from the mother in most multicellular organisms.
They shared the 1975 Nobel Prize with Renato Dulbecco; the enzyme lets retroviruses copy RNA into DNA.
Q 24Barbara McClintock won the 1983 Nobel Prize for discovering transposable elements in which organism?
Maize
She had studied maize chromosomes since the late 1920s and was the sole winner of that year's prize.
Q 25Thomas Hunt Morgan's 'Fly Room', where he tied genes to chromosomes, was at which university?
Columbia
He won the 1933 Nobel Prize and later moved to Caltech, but the famous room was in Schermerhorn Hall.
Q 26Frederick Sanger won his second Nobel Prize in Chemistry in 1980, sharing it with Paul Berg and whom?
Walter Gilbert
His first, in 1958, was for sequencing insulin; only a handful of people have won two Nobels.
Q 27Paul Berg's 1980 Nobel Prize recognised his pioneering work in which field?
Recombinant DNA
The first papers describing successful recombinant DNA came from Stanford and UCSF in 1972 and 1973.
Q 28Which biochemist co-founded Genentech with Robert Swanson in 1976?
Herbert Boyer
It went on to produce the first recombinant human insulin.
Q 29Sir Alec Jeffreys developed genetic fingerprinting in 1984 at which university?
Leicester
He had moved there in 1977 after a fellowship in Amsterdam, and the city made him an honorary freeman in 1992.
Q 30Colin Pitchfork, the first person convicted of murder using DNA profiling, was sentenced in which year?
1988
The same profiling first cleared an innocent suspect before catching Pitchfork, who had murdered two girls in Leicestershire villages.