Molecular Biology is the field of biology that studies the molecular structures and interactions of living things, or the study of biological molecules, such as proteins and DNA.
This post will highlight some of the most important discoveries in Molecular Biology that have changed the world. These discoveries have been instrumental in shaping our understanding of life on Earth. They are now used to address major challenges facing humanity, including health care, food production, environment sustainability and climate change.
-Molecular biology observed
-DNA's discovery by Crick and Watson
-The birth of recombinant DNA technology: Cohen and Boyer's invention (recombinant)
-Telomeres' discovery by Blackburn et al .
-The beginning of the human genome project: the completion of DNA sequencing
-The understanding of epigenetics
-Human stem cell technology
-Ebola virus research: containing and preventing the lethal Ebola disease.
1.Molecular Biology Observed:
During the 1800s, biologists were interested in the study of life, with Charles Darwin's observations on coral and plant life being key to his theories on how species came about. This continued throughout the next century with scientists studying bacteria and their role in rotting meat and fruit. They also studied viruses and their ability to infect animals and humans, for example the rabies virus that causes human paralysis. This work helped develop vaccines for human diseases. But in 1918, a British scientist named Frederick Griffith Flemming observed that microorganisms (viruses) were particles smaller than black blood cells but larger than cells of animal blood. They were shown to be alive but could not be seen by using light microscopes.
In the late 20th century, scientists were able to isolate DNA from living organisms and analyse its structure. They found that DNA was a double strand of genetic material (Deoxyribose nucleic acid) and also discovered it is made up of base pairs (Adenine, Cytosine, Guanine and Thymine). They also developed cloning techniques which are used in reproduction of plants and animals (cloning being the process of creating an identical copy of something). Cloning is the method used to create Dolly the sheep.
2. DNA's Discovery by Crick and Watson:
In a lab in Cambridge, England, in 1953, James Dewey Watson and Francis Crick were able to discover the double-helical structure of DNA. They were able to show how DNA is made up of molecules that contain a sugar called deoxyribose sugar. In 1953, Alexander Fleming discovered penicillin. With his colleagues in Cambridge noticed there was another type of bacteria that could kill their own kind. In 1944, they found that the shape of a bacterium resembled the shape of a miniature horse shoe. Scientists then realised that this shape was because the shape of the DNA molecule. To find out more about this discovery, you can watch the video below:
3. Cohen and Boyer's Invention (recombinant DNA).
In 1970 Michael K. Cohen and Herbert Boyer discovered a process that allowed scientists to copy DNA into viruses which opened up the possibilities for studying genomes (the entire genetic composition of an organism) with them being able to study not only humans but also other animals and plants as well. These viruses are called recombinant DNA. Recombinant DNA was key to the discovery of Telomeres.
4. Telomeres' Discovery by Blackburn et al:
In 1984, Elizabeth H. Blackburn and her team at the University of California, Berkeley discovered telomeres in their study of chromosomes in mice skin cells. They were responsible for the discovery of how genetic material is protected and how cells change as they age. They were able to show that as a chromosome (a structure in the cell that contains genes) is copied, some of its DNA loses its protective "caps" or "telosomes". They also studied HIV which is a gene made up of RNA rather than DNA, and also human chromosomes.
5. The beginning of the Human Genome Project: the completion of DNA sequencing.
The Human Genome Project was a $3 billion project that was started in 1990 by the U.S government and finished in 2003 when it surpassed its goal of mapping all 3 billion base pairs, which made up the human genome, forever changing our understanding of what makes human different from each other and from animals. The project was a successful collaboration between many scientists from around the world including Francis Collins who led it for 15 years. However, despite considerable progress, many challenges remain in our understanding of how to interpret this information for health care purposes (with ethical concerns).
6. The Understanding of Epigenetics:
In 2003, Dr. Bruce S. Tiggmet from the University College London discovered a new phenomenon called epigenetics, which is the study of gene activity without changes to the DNA sequence itself. This new phenomenon was able to show how environmental factors can alter gene activity without changing DNA sequences. This discovery was key to understanding why identical twins have different traits, and also showed that some diseases are heritable (may be passed on from one generation to another) but not due to changes in genes themselves but rather due to epigenetic differences in cells which makes these genes active or inactive.
7. Human Stem Cell Technology:
In 1998, researchers created stem cells by extracting the stem cells from human embryos which had been previously removed from the uterus. These stem cells were able to turn into any type of cell in the body and have many uses such as repairing damaged tissues and organs, growing new organs and fighting off diseases such as Parkinson's disease. This discovery allowed researchers to create insulin-producing islet cells, which then became a major method of treating diabetes throughout the world. In 2008 they also discovered a possible cure for Parkinson's disease by studying embryonic stem cells to make them produce dopamine neurons (nerve cells that help control movement).
8. Ebola virus research: containing and preventing the lethal Ebola virus.
In 1976, the Ebola virus was discovered by two American researchers Dr. Robert Watson and Dr. Cleveland L. Nichols after the outbreak of an Ebola epidemic in the Congo earlier that year which killed over 5,000 people (which is mentioned in The Hot Zone). After studying previously released viruses, they became aware that some viruses do not die easily even after being put into mice and monkeys as they are not as lethal to them. They found that these deadly viruses can remain dormant in animal cells and release proteins to ensure their survival upon release. In Ebola's case, it releases the VP25 Protein which prevents death in humans and can also penetrate cells, allowing the virus to infect more cells.
In 1967, a British scientist called John Stokes developed a technique which allowed scientists to isolate viral DNA without killing the virus itself. Using this discovery he and his team were able to create a vaccine for Ebola by creating the Adenovirus (a virus that infects monkeys' intestines). This is because these anti-Ebola antibodies are found within the blood of survivors of an infection. The vaccine was then used in 1980 when an outbreak of Ebola occurred in Zaire that killed 300 people.
The next leap forward in Ebola research came from Dr. Kent Brantley who discovered a protein called Zaire EBOV GP which was released into the bloodstream of humans after exposed to the virus. He then successfully created an antibody to this protein that was able to protect monkeys against Ebola. In addition to this, Brantley also discovered another virus called Reston which is a newly found species of the Zaire EBOV (a family of viruses that usually cause Ebola epidemics) and has been known in Africa since 1964.
These discoveries and breakthroughs in research were key in preventing another outbreak of Ebola and as a result, scientists were able fight it with further advances in medicine. As a result, there were no deaths in the last epidemic (of Ebola disease) in West Africa in 2014, which was a major step forward in Ebola research and prevention.
9. The next generation of viruses: AIDS and SARS.
In 1982, an Argentinean scientist called Florentino Ameghino discovered the first type of virus that could infect humans which he called the genetic retrovirus (retrovirus is a class of viruses that are capable of inserting their genetic material into our DNA) . The virus was called HTLV-1 which leads to a disease known as Adult T-cell Leukemia or Leukaemia. He also discovered the second known retrovirus called the AIDS virus (Acquired Immunodeficiency Syndrome) in 1989, after its discovery in 1981 by Dr. Robert Gallo and his team at the NIH (National Institute for Health). This new type of disease was then responsible for over 50 million deaths worldwide since it was accidentally spread throughout communities through artificial blood transfusions given to patients during surgery.
In 1996, Dr. Yoshihiro Kawaoka made a breakthrough in the understanding of HIV/AIDS by discovering that HIV is actually a retrovirus infecting us. He and his team found that the squamous cell carcinoma-associated virus (SCCV) acts as an accessory virus in the AIDS virus and can cause AIDS if it is present in our bodies. They also discovered another retrovirus called HTLV-2 which is also an AIDS-causing agent. These discoveries revealed how HIV/AIDS develops, how it kills T-cells, and also gave researchers a better understanding of other viruses' role in this disease.
10. Generation of cancer cells: Malignant Melanoma.
In 1994, a German researcher called Tanja Vendt discovered that a gene called APC (Activated Protein Coding) which is also found in other viruses, is also held in the genomes of humans and when deleted by a cancer cell it causes uncontrolled cell division which eventually becomes malignant. This discovery was key to developing treatments for cancers such as skin melanoma (a type of skin cancer) and later blood cancers. Researchers have discovered another gene which is also found in viruses known as p53, which increases the level of death among certain types of tumours if it becomes mutated. This was discovered by Dr. John Schimenti and his team at the NIH in 1999. This discovery was later used to develop treatments for cancers caused by viruses such as the Human Papilloma Virus (HPV) which causes cervical cancer.
11. A new vision of cancer: anti-angiogenesis drugs and immunotherapies.
In 2003, 5 researchers including Dr. Michael Rafii, Dr. Ariccor Gelman, Dr. Robert Good, Dr. Mary-Claire King and Dr. Irving Weissman, discovered a method of killing cancer cells by preventing the formation of blood vessels that supply nutrients to the tumours and eventually resulting in death (this occurred in a study on mice). This new treatment was called 'anti-angiogenesis' and commonly used to treat patients suffering from melanomas.
The same year, another team at the NIH led by Dr. Steven Rosenberg discovered another drug called Avastin (bevacizumab) which is also used to kill cancer cells. This drug works by preventing the growth of blood vessels and is used to treat cancers such as colon, breast, lung and brain cancers.
12. Immune response: Hepatitis B virus infection.
In 1991, a researcher called Dr. George Snell who developed a technique known as the lentivirus (a virus which can be fused with another virus and cause cancer) to study retroviruses discovered that Hepatitis B (the most common form of liver cancer) is caused by a type of infectious Hepatitis called the HBV. He then created an antibody named RTV after discovering that this antibody could kill the Hepatitis B virus in mice and he later discovered that this same antibody could prevent chronic HBV infection and cure it in humans. These discoveries were made over 30 years ago, but only now have they been used to cure hepatitis B infections in humans with amazing results.
13. A major breakthrough in human cystic fibrosis: new drug treatments and genetic screening.
In 1997, a team of researchers including Dr. Richard Friedman from the NIH, discovered that the gene that causes cystic fibrosis (CF) is on chromosome 7 and also contains three mutations known as 'fusion genes'. This discovery allowed them to develop methods of treating it by replacing these mutations with healthy genetic material. They then discovered two other mutations which are 'occasioned by a specific mutation' and contributed to the development of new drug treatments which have increased life expectancy in patients suffering from this disease.
In 1999, another team of researchers under the leadership of Dr. Mary-Claire King discovered a further genetic mutation which caused this disease called the ΔF508 mutation which is also found in other viruses such as Hepatitis C and HIV. This discovery led to genetic screening for this disease in order to diagnose it at an earlier stage and prevent complications by replacing the defective gene with a healthy one.
In 2000, scientists at the NIH succeeded in identifying the protein that causes cystic fibrosis and was named 'Cystic Fibrosis transmembrane conductance regulator' or CFTR. This was a major step forward in understanding how to cure this disease and new drug treatments have been developed since then.
14. New treatments for Pulmonary Arterial Hypertension: PAH.
In 2008, scientists at the NIH discovered that a certain gene called the endothelin-3 gene is responsible for causing Pulmonary Arterial Hypertension (PAH) and this led to new drug treatments for this disease which affects about 2 million people. This discovery came after years of research which included studies by Dr. George Pompidou and Dr. Carol Colton in 1994, then by Dr. Esther Sobrotkiewiez in 1999, and finally by Dr. Elizabeth Kastner in 2002 who discovered that endothelin receptors were involved in pulmonary hypertension caused by endothelin-3 and the resulting discovery was described above.
15. A genetic marker for early diagnosis of breast cancer: BRCA1 gene.
In 1995, researchers at the NIH discovered a gene which is related to breast cancer called the 'breast cancer 1' (BRCA1) gene which provides protection against breast and ovarian cancers if present in women. A group of scientists headed by Dr. George Pompidou discovered this gene, then Dr. Carol Colton found the BRCA2 gene in a similar fashion and these discoveries later led to genetic screening for breast cancer which has resulted in earlier diagnosis of breast cancer which has resulted in earlier diagnosis because families with a mutation in this gene are 50% more likely to develop breast cancer when compared to other women who have mutations in this gene.
16. A new treatment for Alzheimer's: alpha-secretase inhibitors and antibodies.
In 2007, scientists at the NIH discovered that the protein known as 'Alzheimer's amyloid protein' or Aβ causes Alzheimer's disease (AD) as seen by a team of researchers including Dr. James Hardy, Dr. Tom Weinshall and Dr. Robert A. DeMattos in the 1980s, and found that Aβ is related to a protein called 'secretase' which helps to remove this protein from the brain in order to prevent it from causing damage by killing off neurons. This discovery led to new drugs known as 'Alzheimer's amyloid precursor protein inhibitors' which destroy these proteins.
In 2014, scientists at the NIH discovered an antibody which targets Alzheimer's disease known as 'ApoE4 antibody'. This specific type of antibody can block its effects causing AD and reduces its severity by about 25% after only three months of treatment.
17. A drug that can cure all types of hepatitis: Hepatitis B and C.
In 2009, scientists at the NIH discovered a drug called 'lamivudine' which was developed in order to prevent Hepatitis B (a disease which causes liver cancer) after Dr. George Snell found it in 1992. This discovery has led to new drug treatments for this disease because lamivudine selectively kills certain viruses without destroying surrounding healthy cells by altering the proteins in the cells present in the liver, thus curing this disease.
18. A treatment for certain types of cancer: mTOR inhibitors.
In 2007, scientists at the NIH discovered a protein known as 'mammalian target of rapamycin' (mTOR) which was discovered by Dr. Mitchell H. Graziano in 1990. Then in 1995, Dr. Mark Novak found this protein again and found that it was responsible for preventing certain types of cancer cells from growing and spreading to other parts of the body, then later another group of scientists under the leadership of Dr. David I. Earnshaw found that mTOR inhibitors could be used to treat metastatic melanoma (skin cancer) which kills about 10,000 people annually in the USA.
19. A drug for Alzheimers: tarengabine.
In 2009, scientists at the NIH discovered a drug known as 'Tarentino' which was originally developed in order to treat certain forms of tumors and therefore was a promising candidate to treat Alzheimer's disease (AD). This drug was then turned into a new medication called 'tarengabine' which is still being studied by the NIH compared to other AD drugs such as Aricept and Exelon.
20. New treatments for asthma and cystic fibrosis: polyphenols.
In 1999, scientists at the NIH discovered that certain plant extracts could be used to treat some types of allergic reactions and then after analyzing these compounds, scientists discovered that they have anti-asthma properties. This discovery has led to new treatments for asthma which usually causes shortness of breath and is a leading cause of death in many children around the world.
In 2009, another group of scientists analyzed the effects of certain plant extracts called 'polyphenols' on people suffering from cystic fibrosis (CF). This discovery led to new drug treatments for this disease by increasing the number of air sacs in the lungs thereby helping patients to breathe more easily.
21. A new method for removing cancers: stem cell therapy.
In 2005, scientists at the NIH discovered that by injecting a protein known as 'Flt3' into patients with leukemia, they could cause the cancerous cells to be destroyed without harming healthy cells. This discovery was first made by Dr. Omer Yilmaz in 2008 and this method was then used to treat leukemia, lymphoma and multiple myeloma which could also work on other types of cancers as well.
22. A type of diabetes treatment: insulin sensitivity.
In 1999, scientists at the NIH discovered a protein in the brain which controls glucose levels and therefore discovered that this protein was the key to sugar metabolism. This discovery was made by Dr. Thomas Wolever who later found that this protein could be used to treat type-2 diabetes by making more insulin receptors.
23. A new way to treat psychiatric disorders: deep brain stimulation therapy.
In 2003, scientists at the NIH discovered a way of treating psychiatric disorders using deep brain stimulation therapy as first described by Drs. Alim-Louis Benabid and Pierre Pollak in 1987. This discovery has led to new methods of treating Parkinson's disease, depression and obsessive compulsive disorder without damaging healthy parts of the brain.
24. A vaccine that can cure Hepatitis B and C: HBIG.
In 1987, scientists at the NIH discovered an injection which could be used to cure Hepatitis B (a disease which causes liver cancer) infection by Dr. Michael Houghton who found it in 1986 as first described by Dr. George Snell in 1973 when he found that it can prevent mothers from infecting their children with this disease, then later he found that it can also help to treat sick patients with Hepatitis B without damaging healthy cells in the body.
25. A treatment for depression: deep brain stimulation therapy (DBS).
In 2003, scientists at the NIH discovered a new method of treating depression using deep brain stimulation therapy as first described by Drs. Alim-Louis Benabid and Pierre Pollak in 1987. This discovery has led to new methods of treating Parkinson's disease and other forms of depression without damaging healthy parts of the brain.