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Curious: The Sixth Seminar
by Young Researchers

Positive Phase of
Genetic Recombination

• Is genetic recombination useful? How is endoscopic surgery done? What is the most effective way for patent filings? Three young Japanese researchers in Chicago presented curious seminars about their studies at the Japan Information Center of the Consulate General of Japan at Chicago on January 25.
• The researchers have formed the Japanese Researchers Crossing in Chicago to help each other and held meetings to share their studies. They also have invited people who are interested in learning new things.

• This time, Kohei Kurosawa, Postdoctoral Scholar at the University of Chicago, spoke about “Greatly Flourishing Genetic Recombination”; Ryota Tanaka, Postdoctoral Fellow at the NorthShore University Healthsystem, spoke about “Endoscopic Surgeries by utilizing simulations”; and Kazuhide Hara, Research Scholar at the Department of Chemistry, Northwestern University and University of Chicago, spoke about “Let’s Deliver a Smile with Patents.”

Greatly Flourishing Genetic Recombination

• Genetically modified corn, for instance, may give you a negative image, but researcher Kohei Kurosawa’s images are different. His images are:
• Genetic Recombination protects our health.
• It is necessary for bearing offspring.
• Research theme for every day.
• Genetically modified plants.
• Gene therapy.

Genetic Recombination for our health

• Our bodies have protection from disease-causing germs, but do we have gene information to resist all those germs? He said, “We don’t have it to fight with any germs because too many different germs existed.” So how do our bodies make resistance? He said, “You can find the answer in the menu of 31 Ice Cream.”
• The 31 Ice Cream has 20 flavors. If you order single scoop, only 20 flavors are available; however, if you order triple scoops, you can enjoy 8,000 different combinations. The same phenomenon occurs in our bodies.

• In our bodies, an antibody sticks to a germ and kills it. Antibodies are produced in B cells. An antibody gene is consisted of three kinds of gene, V, D, and J, and each one is consisted of slightly different elements. For example, V is consisted of slightly different V elements.
• When a DNA in a B cell is partially damaged by some stimuli, the DNA works to mend the damaged part by a cut and paste of genes within the cell. The cut and paste occurs randomly, and countless kinds of antibodies are produced by genetic recombination.

Necessary phenomenon for bearing offspring

• The cell division phenomenon is well known. Each of the paternal DNA and maternal DNA is duplicated, and the same two cells are produced. The meiosis, reduction division, which occurs in cells in testes and ovaries, is more complicated. After each of the paternal DNA and maternal DNA is duplicated, the paternal one and the maternal one are shuffled randomly. In this way, sperms and eggs are produced. Kurosawa said, “DNA is active and moves freely.”

• “The genetic recombination would have a negative image, but a very hopeful technology for patients who are suffering from inveterate diseases. It is a necessary technology for the human future,” Kurosawa explained. However, pinpointing an exact place on DNA is very difficult. On the other hand, cells have a tendency to take in other DNA; thus, inserting different genes into a cell is easy. “But putting them in a particular part of DNA and curing a disease is difficult,” he said.

A Brief Account of Genetic Recombination System

• First, DNA has to be damaged. Second, recombination occurs when the damaged DNA begins to mend itself. Artificial recombination can be done during the mending process. He said that damaging a certain part of DNA would be possible, but finding an efficient function to mend damaged DNA would be pretty difficult.

• DNA is damaged by any stimulus. The damage means not a simple cut, but the section is ragged, so the DNA looks for a similar genetic sequence within a cell to make up the damaged part, and then pastes it.
• When a paternal DNA is damaged, the surrounding part of the damaged spot is deleted. Then the DNA gets into a maternal DNA to find a similar genetic sequence and pastes it to the damaged and deleted place.

• This kind of DNA function is utilized to gene therapy. For example, when DNA is consisted of four genes, A, G, T, and C, genetic recombination occurs if a similar sequence of gene, AGTC for example, is placed into a damaged DNA. A cell of yeast has 15 similar sequences, so that genetic recombination easily happens. In the case of a human cell, about 5,000 gene sequences are needed for both sides of damaged DNA, so that genetic recombination does not occur. In other words, human genetic recombination is not efficient.

• Damaging a certain part of DNA has been studied by many researchers. In 2012, a technology for damaging DNA, which was called Crispr Cas9, was discovered by two female scientists. Six months later, two other scientists confirmed that Crispr Cas9 worked for animals. Kurosawa said that the discovery gave a big impact to researchers.

• At the end of his presentation, Kurosawa said, “Although genetic recombination gives you a little negative image, I want you to see the positive side of it because it’s very important technology to contribute to the human future.”


When a DJA in a B cell is partially damaged by some stimuli, the DNA works to mend the damaged part by a cut and paste of genes within the cell.


After each of the paternal DNA and maternal DNA is duplicated, the paternal one and the maternal one are shuffled randomly.

A damaged paternal DA gets into a maternal DNA to find a similar genetic sequence and pasted it to the damaged and deleted place.

Researcher Kohei Kurosawa