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For the longest time, the way in which hereditary information is passed down from one generation to another had not been known. Soon, we found that there are chromosomes in our cells that contain genes through which information is passed on. This was the most we knew in the field of genetics until the work of Prof. Barbara McClintock came along. She had single-handedly discovered what we now know as ‘jumping genes‘. She proved that genes have the ability to jump from one position to another within a chromosome!

The rugged journey to cytogenetics

Prof. Barbara McClintock was born in a time where women were not encouraged to take up any higher degree, let alone a science degree. Facing huge opposition from her mother when she wanted to become a scientist, she joined the Cornell College of Agriculture. Here, she completely fell in love with plant biology and pursued her career in the study of genetics. She was very keen on studying them because she was taken back by the differences that we see in each plant.

Corn specimens that were used in her research
Corn specimens that were used in her research (Source: nobelprize.org)

Even though she struggled to find a job in research, she was soon hired as an assistant professor at the University of Missouri. Teaching was not her forte, so she left to pursue a purely research-based career. This is where she began her full-fledged work on corn kernels that gave her the big breakthrough.

Selfish genes?

She noticed that corn kernels had different patterns of colors between each generation and sparked her curiosity. She assumed that they were because of mutations but that could not be in. Observations suggested that certain genes within the chromosomes had the ability to rather move between different positions. We now know this process as ‘transposition’ and there was definite proof of it. This is why each generation had different phenotypic (external) features!

Corn kernels with different colours and patterns
Corn kernels with different colours and patterns (Source: nobelprize.org)

She held off on publishing any of this work because it was very unconventional at the time. Even when she did, she was rather mocked because it went against the genetic theories that were already proved. Not only that, she observed that when the genes moved, they had the ability to influence those around them. They were acting as ‘controlling elements‘ in this case and that was unusual. This was completely unheard of and that is why it was taken up well in the scientific community.

She laid off from the public eye for a long time concentrating only on her research. She described the experience as rather pressure-free since she didn’t have to convince anybody. Thirty years later, when the same phenomenon was observed in other experiments, her ideas were credited.

Impact of her discovery

The impact of her discovery was huge as it holds the doorway to many questions in the field of evolutionary biology and genetics. Many researchers now use them as a means to induce mutations. They have been implicated in many diseases such as hemophilia, SCID, cancer, even Alzheimer’s. Only because of her discovery we know that such elements exist and can really change the genetic makeup of an organism!

Prof. Barbara McClintock’s story is one of grit and determination. Her carefree attitude is something we would now be envious of. The pressure of publishing and being scientifically correct is something most academics battle with. She could continue her research without any input from others which helped her expand her horizons.

References

Barbara McClintock (2020). Retrieved from https://www.nobelprize.org/womenwhochangedscience/stories/barbara-mcclintock

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