AP Biology class blog for discussing current research in Biology

Tag: Radiation

A NEWclear Life

In a recent study at the University of Georgia, images of many different species of animals have been taken in Fukushima, Japan, where there was a nuclear disaster nine years ago. The people in the area had been evacuated to a safer place so that they wouldn’t suffer from the toxic radiation that causes cancer. However, animals like the wild boar, black bear, macaque, and raccoon dog (my pick for March Mammal Madness 2017) have been photographed in the area. Intrigued by how this could be possible, a team went to take data by taking tens of thousands of images of the different species.

Cameras were set in three different zones: high radiation, intermediate radiation, and low radiation. Humans are still inhabiting the low radiation area because it is safe enough where there is minimal contamination. Despite the nuclear contamination, most of the species inhabited the high radiation zone and the least inhabited the low radiation zone. 26,000 images of wild boars were taken in the uninhabited zone, 13,000 images in the restricted zone, and 7,000 in the inhabited zone. This was due to the fact that the animals were trying to stay away from human interaction and development. The team also evaluated the time of day when the animals were active, the elevation, and the type of terrain. Animals like the raccoon continued to be nocturnal in the uninhabited zone, while the wild boar was even more active during the day than before since it did not have to worry about being hunted. The Japanese serow differed from the rest of the animals as it actually spent more time in the human-inhabited zone because of the higher boar population in the uninhabited zone.

Although many would assume that animals would stray away from areas of high radiation like humans, the contrary occurred in Fukushima. The results showed that factors like human interaction, elevation, and habitat type played a larger role than the radiation levels for population size. How do you think these animals are able to survive in these conditions?

How Ionizing Radiation Damages Genetic Material and Causes Cancer


All around us there is ionizing radiation. It comes from the sun as Ultraviolet rays, in medical equipment as X-rays or Gamma rays, or even from lightning bolts. But what is Ionizing radiation and why is it considered so dangerous. Ionizing radiation is a form of high energy that removes electrons from materials that it comes into contact with. When ionizing radiation comes into contact with cells, it damages them by either directly breaking the bonds between DNA or by ionizing water. Ionized water creates free radicals that then move around and damage DNA. The damage DNA then leads to cancer, but it has never been discovered what types of cancer ionizing radiation causes. However the Wellcome Trust Sanger Institute has finally been able to identify two types of DNA damage caused by ionizing radiation. From previous studies, it has been revealed that radiation damage on DNA leaves a specific fingerprint. By mapping the DNA damage found in cancer cells that were caused by radiation and comparing them to regular cancer cells, the scientists found two mutational patterns that were common in all forms of radiation induced cancers. The first pattern is a deletion of small DNA bases. The second pattern is called balanced inversions, which is where a middle piece of DNA is cut out and attached back to the end. Balanced inversions are not found naturally and can only be caused by radiation damage. From this discovery, scientists hope to be able to identify radiation caused tumors against regular tumors. This may help in finding a specific and more effective cure for the different kinds.

How DNA damaged from radiation causes cancer

In a recent study, professors from the Wellcome Trust Sanger Institute sought to see the similarity between spontaneous cancerous tumors and cancer caused by ionized radiation. By looking at the molecular fingerprint of different types of cancers, they were able to differentiate between cancers that formed by radiation and cancers that were not formed by radiation.

In the study, they studied the mutational signatures of the DNA. Mutational signatures are just ways in which the DNA is affected by cancerous mutations. They studied the DNA mutational signatures from DNA exposed to radiation, but not necessarily cancerous, and the mutational signatures of the DNA of cancerous cells of which some were caused by radiation exposure and some were not. Both included the same signatures.

The two mutational signatures that were observed were deletion of segments of DNA bases and balanced inversion, where the DNA is cut in two places, the middle piece flips around, and the pieces are joined back in the opposite orientation from before the flip. High energy radiation is the cause for balanced inversion, since it does not happen naturally in the body. After the mutation, the DNA cannot repair itself.

This gives us a better understanding of cancer and how ionized radiation affects DNA and produces these mutational signatures. Knowing this information, this helps us recognize which tumors are caused by radiation. Once we have a better understanding of this, it will prove important for determining how each cancer should be treated. But for now, this is a strong step forward in the battle against cancer and every step of the way is crucial if we are to be victorious.


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