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Sequencing DNA
The first DNA sequencing methods were invented in the late 1970s, but pure DNA, ready for sequencing, was
difficult to produce—thus, making DNA sequencing labor- and time-intensive compared to other tools for
making indirect inferences about genetic sequences. However, in the late 1980s, scientists developed a
technique for producing many, many copies of a very small amount of DNA, and this invention sparked an explosion
in the study of DNA sequences. Researchers began to rely upon sequences as a crucial source of evidence for
evolutionary relationships.
Sequencing genes seems to become easier every day. Ten years ago, it
might have taken an hour to sequence 10 base
pairs. Today a typical lab can sequence 100 base pairs in an hour and
facilities with the latest technology sequence hundreds of base pairs
each minute. We are now awash in genetic code—we have a basic map
of the human genome and the genomes of many other organisms. However,
DNA sequences alone do not answer all the questions that biologists ask,
and knowing a gene’s sequence is still many steps away from understanding
how it actually works and what it does. DNA sequences are only one line
of evidence illuminating evolutionary relationships. For example, human
and chimpanzee DNA is 98% identical, and genetic sequencing can tell us
exactly where in the genome those few DNA differences are—but anatomical,
behavioral, and developmental studies are also crucial in deeply understanding
our differences, similarities, and shared evolutionary history.
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Machines that automatically sequence DNA have made those sequences readily available for evolutionary research. |
