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Serendipity in Biology

Have you ever come across the term ‘Serendipity’, or is it new to you? Serendipity is a happy and unexpected event that occurs by chance and happens when we are searching for a particular thing, but discover something else! The general conception is that scientific research goes on in a methodical, precise, and controlled way. The word “by chance” or “accidentally” may sound odd in the field of science, but the “by chance” incidents have indeed played a major role in several scientific inventions.

What people call serendipity sometimes is just having your eyes open. Jose Manuel Barroso

The phrase “by chance” does not imply capriciousness of nature. Rather, it means that a researcher has made an unexpected discovery due to the specific procedures they chose to follow in their experiment. Those procedures led to serendipity, while another set of procedures may not have yielded revelations. Some scientists even try to design their experiments in a way that increases the chances of serendipity.

Instances of serendipitous discoveries Serendipity gifted us a number of drugs and medical treatments including vaccines, quinine, viagra and insulin.

Penicillin along with Lysozyme: Alexander Fleming discovered the first ever antibiotic- penicillin- in 1928, but at that time he was not searching for any compound that arrests the growth of microbes. He was studying the Staphylococcus bacterium and noticed that a blue-green mould had contaminated a petri dish, killing all the surrounding bacteria in the culture.

Earlier, in 1922, Fleming had accidentally shed a tear onto a bacterial culture plate and noted that the spot where the tear landed was free of the bacteria that grew around it, denoting that there was something in the tear that halted bacterial growth. This enzyme is present in our mucus, saliva, and tears. Fleming found the enzyme after he sneezed on a petri dish full of bacteria. He noticed that some of the bacteria died where the mucus had contaminated the dish. Thus, he serendipitously discovered the enzyme lysozyme.

Six years later Fleming remembered his teardrop experience and concluded that the fungus growing in the petri dish was killing the powerful Staphylococcus bacteria by secreting some compound. He isolated and identified the fungus as belonging to the genus Penicillium and named the active bacterium-killing agent secreted by the mould as penicillin.

Penicillium mold fungi

Cis-platin: It is a complex compound first made in 1844 by an Italian chemist named Michele Peyrone and is sometimes known as Peyrone’s chloride. But how did it become an anti-cancer drug?

Dr. Rosenberg found that the bacterial cells that survived were lengthening because they were unable to divide, indicating that cis-platin is able to arrest cell-division. Thus, the idea of cis-platin being used as an anti-cancer drug came about.


Sucralose: In 1975, scientists at the Tate and Lyle sugar company and King’s College London were working together to find a way to use sucrose (sugar) as an intermediate substance in chemical reactions unrelated to sweeteners. Shashikant Phadnis, a graduate student helping with the project, was asked to “test” some chlorinated sugar being prepared as a possible insecticide, but he misheard the request as “taste”. He placed a little bit of the chemical on his tongue and found that it was far sweeter than sucrose. Luckily, it was not toxic! Thus, this chloride derivative of sucrose- sucralose- was discovered, and is currently one of the most common artificial sweeteners.

Saccharin: In 1877, H.W. Perot Company hired Constantin Fahlberg to test the purity of a shipment of sugar. One day, after working in the lab, Fahlberg started tucking into his meal when he noticed that the bread roll he’d just taken a bite out of tasted incredibly sweet. After ruling out the possibility of the bread roll being made that way, Fahlberg concluded that he must have accidentally spilled a chemical onto his hands. Rather than immediately sticking his finger down his throat and throwing up, Fahlberg reportedly became very excited at the thought of his discovery. The first non-toxic artificial sweetener was discovered just because the scientist didn’t wash his hand properly after eating!

Lysergic acid diethylamide: In the late 1930s, a new procedure was developed that allowed combining lysergic acid with amides in peptide linkage. Hofmann prepared lysergic acid diethylamide, a substance structurally related to the circulatory stimulant nikethamide, to develop an analeptic. Since the substance was the 25th compound of the lysergic acid amide series, it was given the code name LSD-25. In pharmacological testing, LSD-25 produced uterine contraction, similar to that of ergometrine. Fixation was observed in some animals after LSD-25 administration. Thus, the hallucinogen LSD was invented.

Recent serendipity in Genetics: Recently, a team of Chinese scientists performed a genetic modification using the CRISPR/Cas9 technique to delete the CCR5 gene. This deletion should remove a CCR5 receptor which the HIV uses to infect the cell- making the person immune to HIV. The genetic engineering was carried out on twins’ embryos, and the two girls were indeed born without the CCR5 gene and hence without the receptors. There are some humans born without that gene naturally, and it was by observing them that scientists discovered their resistance to the HIV. Hence the Chinese scientists just forced something that may happen naturally. But the interesting thing is, the people deprived of CCR5 gene had better cognitive ability. This revealed that a single gene can affect several phenotypic aspects of a person, which we now call pleiotropy.

Likewise, there are a lot of events and inventions driven by serendipity that have resulted in the invention of something new and useful. Not only within biological science, but in every branch of science, serendipity has gifted us unexpected success and made our scientists smile.

- written by Ankan Ghosh

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