Charles Darwin’s pioneering work in natural selection in the 19th century found that most individuals in a population were fairly similar- genetically. With the advent of more sophisticated methods it was proven that the size of a population is also important for natural selection. This theory and other breakthrough discoveries by Dr Tomoko Ohta was the basis for here selection as this year’s Crafoord Prize winner in biosciences.
Professor Tomoko Ohta took the stage at the Crafoord award seminar in what looked like a daze. Over 60 years of work lead to her being selected as the winner of the coveted Crafoord Prize in biosciences. Her work is in the field of evolution.
Her lecture encompassed her work in the field of gene mutations – way back to the 1960’s explains Royal Swedish Academy scientist Kestin Johanesson;
”At that time you didn’t really see anything else than natural selection was important for the change in the populations and organisms,” she said.
Then Dr Ohta hit on something new regarding gene mutations, or a natural process that changes a DNA sequence- not necessarily a bad thing...Just different.
”She came up with the idea that many of the mutations aren’t really bad for fitness, but just slightly bad for fitness. So they are nearly neutral, but not perfectly neutral. In a big population the fate of these mutations will actually be under selection,” explained Johanesson.
Under selection in genetic terms means new generations will inherit some of their parents traits.
If this happens enough, a species or population is then said to have evolved.
Dr Ohta proved that natural selection doesnt’ work as well in smaller populations.
New mutations will have a greater chance to survive in smaller groups, making evolution speed increase.
But Professor Ohta recalls the biting words she heard in the 1960’s when she put forth her theories and was rebuffed by the 100 % male genetic scientist community.
”Oh, it can’t be true. And the population genetics people just did not accept. They had some previously imprecise insights, which was very limiting to their thinking,” she recalled.
Previously it was thought that all individuals in a population had identical genes.
We now know, through DNA analysis, that almost all individuals have different gene sequences, though their species appear outwardly to be the same.
Dr Ohtas breakthrough on nearly neutral mutations has led to advances in a wide range of fields.
DNA analysis now helps to catch criminals. Companies are selling gene tests on the internet to people who want to know whether their genes might bear a trait for a serious disease.
At the break, the buzz among many young genetics researchers was about new angles on Dr Ohtas groundbreaking work.
One of them is Dr. Tomoko Steen, a clinical pharmacologist.
Steen did her PHD on Dr Ohta’s nearly neutral theory. Today she’s emplying that knowledge to help people in the radiation affected area of Fukushima, Japan.
”I care about the people right now, so I went several times to Fukushima. I’m originally from Nagasaki, as well. So discrimination with unfounded science which is a problem. So I’m just looking to get accurate science so that the people can actually know what to do next,” said Steen.
In spite of the attention from the award, Crafoord prizewinner Dr Ohtas is unabashing, giving credit to Darwin.
”I’m just an ordinary scientist but I think in evolutionary thinking, interdisciplinary consideration is very important, This started in the age of Darwin. He actually integrated paleontology recording with geology. So that’s a very different field,” she said.
But sitting in the Nobel room of the Swedish Academy of Sciences, Professor Ohta cracks a smile when asked how she feels today.
”I feel very nice. I’m very happy now,” she said.
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