Discoveries in DNA: What's New Since You Went to High School?

Scientific and technological advances in the last 50 years have led to extraordinary progress in the field of genetics, with the sequencing of the human genome as both a high point and starting point for more breakthroughs to come.

Advances in molecular genetics have propelled progress in fields that deal with inherited diseases, cancer, personalized medicine, genetic counseling, the microbiome, diagnosis and discovery of viruses, taxonomy of species, genealogy, forensic science, epigenetics, junk DNA, gene therapy and gene editing.

For many non-scientists, a recap may be in order. With such rapid progress, the field has moved well beyond the knowledge covered in many biology classes over the years.

If you took high school biology in the 1960s, you probably learned about DNA as the genetic material and the structure of the DNA double helix (published in 1953 by Watson and Crick). You may also have learned about the genetic code, by which the sequences of DNA encode amino acids (worked out by Nirenberg, Khorana and colleagues by 1961).

If you took high school biology in the 1970s, you probably also learned about cloning (worked out by Herb Boyer, Stanley Cohen and Paul Berg by 1972) and the potential for recombinant DNA technology to provide gene therapy, create novel drugs and improve agriculture.

If you took high school biology in the 1980s, you may have learned about the clinical use of recombinant human insulin for diabetes treatment (approved for the Eli Lilly products in the US by the FDA in 1982). In agriculture, the use of Agrobacterium tumefacians as a bacteria-mediated delivery system to transfer recombinant DNA to crops (developed by Mary-Dell Chilton and colleagues in the 1970s) marked the advent of GMO foods and other commercial plant products.

Image courtesy of the National Institutes of Health, adapted by Ellen Hutti.

If you took high school biology in the 1990s, you probably learned about the molecular basis for human genetic disorders such as cystic fibrosis (1989), Huntingtons (1993), Duchenne and Becker muscular dystrophy (1987), and a rapidly growing list of single-gene disorders, and the correspondingly rapid growth in clinical diagnostic technology based on DNA sequence information, enabling certain diagnosis, sometimes before the advent of overt symptoms.

If you took high school biology in the ‘00s, you probably heard about the completion of the human genome sequence. The completion of a “rough draft” was announced by President Bill Clinton and British Prime Minister Tony Blair in 2000, although a more-or-less complete sequence was only finalized in 2006. You may also have learned that this achievement heralded the arrival of the age of personalized medicine.

The big breakthrough in decoding the human genome was the invention of technology to obtain large amounts of DNA sequence, which began in the 1970s with the work of Ray Wu, Walter Gilbert, Fred Sanger and their colleagues to establish the core strategies for obtaining continuous sequence information for DNA chains. This included advances in recombinant DNA technology—for example, the creation of recombinant artificial chromosomes—combined with semi-automated (invented in the Leroy Hood lab in 1986) and later automated DNA sequencing. Today, the goal of obtaining the complete sequence of an individual genome for $1,000 is nearly within reach.

Although it isn’t biology, it must be acknowledged that the human genome sequencing project also required parallel advances in computer speed and storage to acquire, store and manipulate billions of nucleotides of DNA sequence. The assembly and analysis of human tumor cell genomes, many of which contain chromosome deletions, duplications and insertions, as well as single nucleotide changes, requires immense data storage capacity and high-speed computation.



The invention of the Polymerase Chain Reaction (PCR) technology by Kary Mullis and colleagues in 1985 transformed molecular genetics. This had immediate application for DNA diagnostics, because once a gene implicated in an inherited disorder has been identified and sequenced in its normal form, PCR could be used to amplify the corresponding sequences from patient DNA in a matter of hours, with sequencing of the PCR products to identify the exact molecular mutation in a matter of days at that time, and today in a matter of hours. PCR has also seen application in the identification of emerging pathogens.



The findings made by scientists during these decades have led to advances in many different fields. Explore the following topics to learn more about how breakthroughs in molecular genetics are being applied in the world.