50 Fun Facts About Hard DNA

In whose laboratory at the University of Tubingen did Friedrich Miescher isolate 'nuclein' in 1869?

Miescher got his white blood cells from pus on surgical bandages collected at a nearby hospital.

The 1944 Avery-MacLeod-McCarty experiment showed DNA was the 'transforming principle' in which bacterium?

At the time most biologists assumed proteins carried heredity, which is what the very word 'protein' had implied.

The 1952 Hershey-Chase 'blender experiment' used what kind of virus to show DNA, not protein, enters the host?

Phage DNA entered the bacteria while most of the protein coat stayed outside and was knocked off in a blender.

Chargaff's rules state that in DNA adenine equals thymine and guanine equals what?

Erwin Chargaff's ratios were a crucial clue that led Watson and Crick to complementary base pairing.

Meselson and Stahl's 1958 experiment labelled DNA with a heavy isotope of which element?

Nitrogen is in every DNA base, so 15N-labelled parent strands could be separated from lighter new ones by density.

Who actually took Photo 51, the X-ray diffraction image of DNA, at King's College London in 1952?

He was Franklin's PhD student, and it was the 51st diffraction photograph he had taken; Wilkins later showed it to Watson without permission.

After leaving King's in 1953, Rosalind Franklin did pioneering virus work at which London institution?

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.

Watson and Crick's structure paper appeared in which volume of Nature, dated 25 April 1953?

It occupied just pages 737-738, with supporting papers by Wilkins and by Franklin and Gosling in the same issue.

What fundamental chemical error did Linus Pauling's 1953 triple-helix DNA model make?

Neutral phosphates conflicted with the well-known acidity of DNA, and Watson and Crick published the correct double helix months later.

Which Cavendish Laboratory director first publicly announced the DNA double helix in a May 1953 talk?

His talk at Guy's Hospital led to a News Chronicle article titled 'Why You Are You'.

Maurice Wilkins, who shared the 1962 Nobel Prize with Watson and Crick, was born in which country?

He insisted Franklin's name go first when King's College named its Franklin-Wilkins Building in 2000.

Which cytogeneticist established in 1956 that humans have 46 chromosomes, not 48 as long believed?

Painter had counted 24 pairs in 1923, and his error was copied for three decades.

Francis Crick first stated the 'central dogma' in a 1957 lecture; in what year was it published?

It describes the flow of information from DNA to RNA to protein and why it does not run backwards into protein.

The 1961 Nirenberg-Matthaei poly-U experiment produced a protein made solely of which amino acid?

It was the first codon deciphered, showing UUU codes for phenylalanine and cracking the genetic code open.

Reading three bases at a time gives how many possible codons for the 20 standard amino acids?

Four to the third power is 64, so most amino acids are specified by more than one codon and three are stop signals.

Arthur Kornberg discovered DNA polymerase I in E. coli in 1956 and won the Nobel Prize in which year?

His son Thomas Kornberg later discovered DNA polymerase II, and Arthur's other son Roger won a chemistry Nobel in 2006.

Okazaki fragments, the short pieces of the lagging strand, are joined together by which enzyme?

Reiji and Tsuneko Okazaki discovered them in the 1960s; in eukaryotes they run about 150 to 200 base pairs.

Human telomeres consist of several thousand repeats of which six-letter sequence?

Blackburn, Greider and Szostak shared the 2009 Nobel Prize for discovering how telomeres and telomerase protect chromosome ends.

Which two geneticists independently proposed in 1938-39 that chromosome ends had a special structure?

Muller worked with fruit flies and McClintock with maize; the word combines the Greek for 'end' and 'part'.

Human mitochondrial DNA contains how many base pairs?

It encodes just 13 proteins and is inherited from the mother in most multicellular organisms.

Cann and Wesley Brown found that human mitochondrial DNA mutates how much faster than nuclear DNA?

That fast, steady clock underpins the concept of Mitochondrial Eve, the matrilineal most recent common ancestor of all living humans.

Which discovery earned Phillip Sharp and Richard Roberts the 1993 Nobel Prize in Physiology or Medicine?

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.

Reverse transcriptase was discovered in 1970 by David Baltimore and which other scientist?

They shared the 1975 Nobel Prize with Renato Dulbecco; the enzyme lets retroviruses copy RNA into DNA.

Barbara McClintock won the 1983 Nobel Prize for discovering transposable elements in which organism?

She had studied maize chromosomes since the late 1920s and was the sole winner of that year's prize.

Thomas Hunt Morgan's 'Fly Room', where he tied genes to chromosomes, was at which university?

He won the 1933 Nobel Prize and later moved to Caltech, but the famous room was in Schermerhorn Hall.

Frederick Sanger won his second Nobel Prize in Chemistry in 1980, sharing it with Paul Berg and whom?

His first, in 1958, was for sequencing insulin; only a handful of people have won two Nobels.

Paul Berg's 1980 Nobel Prize recognised his pioneering work in which field?

The first papers describing successful recombinant DNA came from Stanford and UCSF in 1972 and 1973.

Which biochemist co-founded Genentech with Robert Swanson in 1976?

It went on to produce the first recombinant human insulin.

Sir Alec Jeffreys developed genetic fingerprinting in 1984 at which university?

He had moved there in 1977 after a fellowship in Amsterdam, and the city made him an honorary freeman in 1992.

Colin Pitchfork, the first person convicted of murder using DNA profiling, was sentenced in which year?

The same profiling first cleared an innocent suspect before catching Pitchfork, who had murdered two girls in Leicestershire villages.

Kary Mullis shared the 1993 Nobel Prize in Chemistry for inventing PCR with which scientist?

Mullis conceived PCR while working at the Cetus Corporation in Emeryville, California.

Most PCR methods amplify DNA fragments of what length?

Some specialised techniques can stretch to about 40 kilobases.

Doudna and Charpentier's teams at which two universities first patented CRISPR-Cas9 editing in 2012?

A third group led by Virginijus Siksnys shared the Kavli Prize for the discovery but was left out of the 2020 Nobel.

Whose 1958 cloning of African clawed frogs laid the groundwork for cloning Dolly from an adult cell?

Dolly, a Finn-Dorset sheep born in 1996, was cloned by nuclear transfer from a mammary gland cell.

Roughly what share of the genome had the Human Genome Project covered when declared complete in 2003?

The remaining gaps were judged too costly to fill; a truly gapless human genome came from the T2T consortium years later.

Celera's private human genome effort cost roughly how much, against the public project's $3 billion?

Craig Venter's company used whole-genome shotgun sequencing to move faster and cheaper.

The human Y chromosome, sequenced completely in January 2022, contains roughly how many base pairs?

A complete female genome (without a Y) had been reported in 2021.

Svante Paabo won the 2022 Nobel Prize in Medicine for discoveries concerning the genomes of what?

He led the sequencing of the Neanderthal genome and is considered a founder of paleogenetics.

In November 2015 scientists reported Denisovan DNA from a tooth roughly how old?

The Denisovans are an extinct human species known mostly from tiny fragments found in a Siberian cave.

The oldest DNA ever sequenced, reported in 2021, came from the remains of which animal?

The remains were over a million years old, far beyond what was once thought possible for surviving DNA.

Which strain of E. coli is the workhorse most commonly used in genetic engineering labs?

It is different enough from disease-causing strains that some argue it deserves reclassification.

Which single-ringed bases in DNA are classed as pyrimidines?

A purine always pairs with a pyrimidine, which keeps the width of the double helix constant.

Which two factors determine how strongly the two strands of a DNA double helix hold together?

G-C pairs have three hydrogen bonds to A-T's two, and longer molecules are more stable, so GC-rich DNA melts at higher temperatures.

Which molecules act as spools around which DNA winds to form nucleosomes?

Nucleosomes are then wound into 30-nanometre fibres to form chromatin.

Katalin Kariko and Drew Weissman won the 2023 Nobel Prize for developing what?

The Pfizer-BioNTech and Moderna COVID-19 vaccines were the first mRNA vaccines authorised for wide use.

In CRISPR gene editing, the cutting enzyme is delivered into the cell complexed with what?

It was adapted from a bacterial antiviral defence system and works like genetic scissors.

Gattaca, the 1997 film, was shot under what working title?

The reference is to the seven days of creation; the final title uses only the letters G, A, T and C.

Which US agencies formally founded the Human Genome Project in 1990?

It was expected to take 15 years and finished in 13.

Which method identified the Golden State Killer in 2018 by matching crime-scene DNA to relatives on a public database?

Investigators uploaded the profile to GEDmatch and built family trees to reach Joseph James DeAngelo.

Sanger's 1958 Nobel Prize came for determining the amino acid sequence of which protein?

It proved proteins have a unique, definite structure, a foundation for the central dogma.