Since the beginning of times, man has tried to discover the secrets of the universe using various disciplines of science. That curiosity to discover and understand everything that surrounds him, and to understand himself, lead to them investing enormous efforts to achieve it.
Surely, one of the first things of his interest was getting familiar with his body – how it works, how does it differ from one person to another, why some physical and mental characteristics are inherited from our parents, or why are some of us more prone to specific diseases that others.
An answer to those questions automatically meant creation of modern genetics, and its founder was
Gregor Mendel in 19th century.
Nevertheless, first true leap in modern genetics was enabled by uprising of technology in the middle of the 20th century, when many theories and experiments could be put to test, and validated.
We present you the timeline of the most important events in genetics in the 20th century.
Gregor Mendel, the father of modern genetics publishes his research on experiments in plant hybridization
In his monastery garden, in period between 1856-1863, he performed crossing of pea plant varieties having different heights, colors, pod shapes, seed shapes. For example, when he crossed yellow peas with green peas, all the offspring peas were yellow. But when these offspring reproduced, the next generation was ¾ yellow and ¼ green. His work, published in 1865, showed that genes determine traits in predictable ways.
Friedrich Miescher discovers „nuclein“ from cell nuclei, DNA with its associated proteins
During his research on white blood cells, he succeeded in isolating a new molecule from the cells’ nuclei and he called it nuclein. Nuclein contained hydrogen, oxygen, and a unique ratio of phosphorus and nitrogen. Even though he spent his whole life studying nuclein, he and researchers of his time considered nuclein as the molecule by which traits passed from parents to children. The importance of DNA wasn’t discovered for many years.
Rosalind Franklin created „Photograph 51“ and shows helical shape of DNA for the first time
Rosalind Franklin was born in London in 1920. After graduating from Cambridge University, she studied x-ray techniques in Paris. The year after her graduation, she moves to London and with Maurice Wilkins molecular biologist, uses X-ray crystallography to study DNA. Finally, using this technology, they create the first photography where the helical structure of DNA was clearly visible.
James Watson and Francis Crick identify the double helix structure of DNA
These two researchers modeled the structure of DNA, which is a double helix, with sugars and phosphates forming the outer strands of the helix, and the bases pointing into the center. Hydrogen bonds connect the bases, pairing A–T and C–G; and the two strands of the helix are parallel but oriented in opposite directions. Their notes show that this model “immediately suggests a possible copying mechanism for the genetic material.”
Marshall Nirnberg cracks the genetic code for protein synthesis
Identifying „UUU“ (three uracil bases in a row) as the RNA code for phenylalanine was the first breakthrough Nirnberg makes in 1961. In the following years, Nirnberg and his team decoded the 60 mRNA codons for all 20 amino acids. In 1968, Nirenberg shared the Nobel Prize in Physiology or Medicine for his contributions to decoding the genetic code and understanding protein synthesis.
Frederick Sanger succeeds in developing the rapid DNA sequencing technique
In order to determinate the order of bases in a strand of DNA, Frederick Sanger developed the classical “rapid DNA sequencing” technique , nowadays known as the Sanger method. For his contributions to DNA-sequencing methods, Frederick Sanger shared the 1980 Nobel Prize in Chemistry.
Huntington’s disease – the first mapped genetic disease
This disease causes death of specific neurons in the brain, leading to jerky movements and dementia. Symptoms usually appear in midlife and worsen progressively. Location of the HD gene, whose mutation causes Huntington disease, was mapped to chromosome 4. This made this gene the first disease gene to be mapped. This gene was finally isolated in 1993.
Polymerase chain reaction (PCR) technology for amplifying DNA was invented
PCR is a pretty straight forward and low cost technology for amplifying or making billions of copies of a segment of DNA, and is considered as one of the greatest scientific advances in molecular biology. Today, this technology is used every day to diagnose diseases, identify bacteria, and viruses. As a proof of how much this technology revolutionized research of DNA is the fact that Dr. Kary Mullis was awarded the Nobel Prize in Chemistry in 1993.
Cystic Fibrosis gene mutation discovered
Cystic fibrosis (CF) is a life-threatening genetic disease that causes thick, sticky mucus to build up in the lungs, digestive tract, pancreas, and other organs. In the early 1980’s, many laboratories tried to identify the gene that causes this disease. Finally, In June 1989, researchers identified a small DNA mutation in 70% of cystic fibrosis patients, while this mutation wasn’t found in healthy individuals. The discovery of the CFTR gene is the single most important discovery to date in research of Cystic fibrosis.
First evidence of BRCA1 gene existence
BRCA1 (BReast CAncer gene 1) is a gene which normally produces a protein that prevents cells from growing and dividing out of control. However, some variations of BRCA1 can disrupt its normal function, which can lead to increased hereditary risk for cancer. The gene was finally isolated in 1994. Today, researchers have identified more than 1,000 mutations of the BRCA1 gene.
The beginning of the Human Genome Project
In 1984, the U.S. Department of Energy (DOE), National Institutes of Health (NIH), and international groups held meetings about studying the human genome. Already in 1990 NIH and DOE published a plan for the first five years of an expected 15-year project. The goal of the project was to develop technologies for analyzing DNA, mapping and decoding human, as well as mice and fruit genomes.
Human Genome Project
The Human Genome Project was a game changer in the study of human genome, because for the first time, researchers from all around the world were gathered around one goal – decoding the human genome.
The project began in 1990, by National Institutes of Health (NIH) and U.S. Department of Energy (DOE). These institutions, backed with consortium of science centers from Great Britain, Germany, Japan, China, France, Canada, and other countries.
Mission was to identify genes that cause diseases, and to use that knowledge in treating those diseases. In order to accomplish this task, they gave themselves a deadline until 2005, and they had a budget was 3 billion dollars.
The idea of the project’s founders was that once they have the results, they will publish them, and put on disposal for free to all researchers, and science institutions.
“Research of the human genome will revolutionize the diagnosis, prevention and treatment of most, if not all, human diseases.”. – Bill Clinton, former USA president
Bill Clinton, former USA president
Decisive step in that direction, founders of the HGP made on a summit in Bermuda in 1996. They agreed that all data and findings any of their research centers about sequencing the human genome , have to be eligible to the public, for free.
These principles boosted further research and development, and they were completely opposite to the practices at that time. Practice at that time was that data based on experiments was eligible to the public only after it has been officially published.
First significant moment, and one that served as a platform for further development of the Human Genome Project in sequencing the human genome, was decoding the first human chromosome – Chromosome 22.
Chromosome 22 was chosen as the first of 23 chromosomes from human DNA to be decoded because it was smaller than others, and it was suspected to cause many rare diseases.
Decoding the chromosome 22 was a cooperation of scientists from USA, England, Japan, France, Germany, and China.
“Decoding the human genome sequence is the most significant undertaking that we have mounted so far in an organized way in all of science. I believe that reading our blueprints, cataloguing our own instruction book, will be judged by history as more significant than even splitting the atom or going to the moon.” – Francis S. Collins, american physician and geneticist
In 2001, this pioneer international consortium publishes its first draft and initial analysis of the human genome sequence.
It’s worth pointing out that Craig Venter and his team from the „Celera Genomics“ private company published his version of the human genome sequence in that same year.
This meant that a wealth of information was now available for researchers worldwide, the number of genes in the report was 20 000. Also, their research showed that the DNA sequences of any two human individuals are 99.9 percent identical.
The Human Genome Project’s ambitious goals had all been met in 2003, as the project finished 2,5 years before its deadline, and it stayed well under-budget.
In summary, duration of the project was 13 years, and they spent 1 billion dollars. In the end of the project in 2003, cost of sequencing the human genome for one person was lowered to 5 000 dollars.
We can say with certainty that the Human Genome Project completed the task it was designed for, which is generating resources for further biomedical studies.
Although scientists thought that sequencing the human genome would bring us to complete understanding of the human organism, it only lead us to the beginning of it. In the past 13 years we have more questions than answers, and most probably, that was the point of this project.
Today, 13 years after the end of the Human Genome Project, we are finally experiencing its real effects. As dr. Aleksander Parker, genomics isn’t just a „promise for the future“, it already has a certain impact in every part of medicine.
Genomics became a strong diagnostic tool, especially for patients with rare diseases. It also transforms tumor treatment, as it enables therapy adaptation to accommodate the specific DNA profile of the patient and the tumor. Pharmacogenomics uses genetic information to specify which medicine and in its dosage in order to ensure the best possible treatment.
The dream of personalized healthcare is real.