Because DNA collects mutations over time, which are then inherited, it contains historical
information, and, by comparing DNA sequences, geneticists can infer the evolutionary history of
organisms, their phylogeny. This field of phylogenetics is a powerful tool in evolutionary
biology. If DNA sequences within a species are compared, population geneticists can learn the
history of particular populations. This can be used in studies ranging from ecological
genetics to anthropology; For example, DNA evidence is being used to try to identify the Ten
Lost Tribes of Israel.
DNA has also been used to look at modern family relationships, such as establishing family
relationships between the descendants of Sally Hemings and Thomas Jefferson. This usage is
closely related to the use of DNA in criminal investigations detailed above. Indeed, some
criminal investigations have been solved when DNA from crime scenes has matched relatives of
the guilty individual.
In a paper published in Nature in January, 2013, scientists from the European Bioinformatics
Institute and Agilent Technologiesproposed a mechanism to use DNA's ability to code
information as a means of digital data storage. The group was able to encode 739 kilobytes of
data into DNA code, synthesize the actual DNA, then sequence the DNA and decode the
information back to its original form, with a reported 100% accuracy. The encoded information
consisted of text files and audio files. A prior experiment was published in August 2012. It was
conducted by researchers at Harvard University, where the text of a 54,000-word book was
encoded in DNA.
DNA was first isolated by the Swiss physician Friedrich Miescher who, in 1869, discovered a
microscopic substance in the pus of discarded surgical bandages. As it resided in the nuclei of
cells, he called it "nuclein". In 1878, Albrecht Kosselisolated the non-protein component of
"nuclein", nucleic acid, and later isolated its five primary nucleobases. In 1919, Phoebus
Levene identified the base, sugar and phosphate nucleotide unit. Levene suggested that DNA
consisted of a string of nucleotide units linked together through the phosphate groups. However,
Levene thought the chain was short and the bases repeated in a fixed order. In 1937 William
Astbury produced the first X-ray diffraction patterns that showed that DNA had a regular
In 1927 Nikolai Koltsov proposed that inherited traits would be inherited via a "giant hereditary
molecule" made up of "two mirror strands that would replicate in a semi-conservative fashion
using each strand as a template". In 1928, Frederick Griffithdiscovered that traits of the "smooth"
form of Pneumococcus could be t