30 questions · 17 almanac · 0 findings

DNA Sequencing

Methods for reading the order of nucleotides in DNA.

Almanac Copying the Copy Itself
  • What modern medical technologies, like PCR testing, trace their origin back to Kornberg's discovery of DNA polymerase?
Almanac A Bacterium That Liked Boiling Water
  • How did an enzyme from Thermus aquaticus enable the polymerase chain reaction (PCR)?
  • Why did DNA polymerase need to be heat-stable for Kary Mullis's PCR technique to work?
Almanac Reading the Code, Letter by Letter
  • How did Sanger's chain-termination method use modified nucleotides to determine the sequence of bases in DNA?
  • Why did Sanger's sequencing method scale better than Gilbert's chemical method, and what large-scale project did that scalability eventually enable?
  • Who else besides Frederick Sanger has won two Nobel Prizes in Chemistry?
Almanac One Found the Trick, One Built the Tool
  • What did Leroy Hood's automated DNA sequencer, introduced in 1986, make possible that hand methods could not?
  • Why did automated DNA sequencing turn the Human Genome Project from a feasibility question into a logistics one?
Almanac Three Billion Letters, Committed To
  • What agencies signed the memorandum that formally launched the Human Genome Project, and what was its budget and timeline?
  • Why was it uncertain in 1990 whether sequencing three billion base pairs was even technically achievable?
  • How far ahead of schedule did the Human Genome Project finish, and what did it make possible for later biology?
Almanac A Billion Copies From One Late-Night Drive
  • How does the polymerase chain reaction turn a tiny DNA fragment into a billion copies?
  • What role do primers and a heat-stable polymerase play in each PCR cycle?
  • Why did PCR make same-day testing possible during a pandemic decades after its invention?
Almanac A Bacterium, Read End to End
  • How does whole-genome shotgun sequencing reconstruct a genome from randomly shattered fragments?
  • Why did many scientists doubt the shotgun approach would work before Venter's team proved it out?
Almanac A Chromosome Read Without a Single Gap
  • Why was chromosome 22 chosen as the first human chromosome to be completely sequenced?
  • What did it mean for the sequence to be 'complete' rather than a draft with gaps and errors?
Almanac Twenty Thousand Genes, Not a Hundred Thousand
  • Which two teams independently produced a working draft of the human genome in 2000?
  • How many protein-coding genes did the completed analysis find, and how did that compare to predictions?
  • Why does the human genome having a gene count similar to a roundworm matter?
Almanac He Raced the Consortium and Tied
  • What is whole-genome shotgun sequencing, and why did the scientific establishment consider Venter's approach reckless?
  • What was significant about Venter becoming the first person to have his genome sequenced by name?