Chernobyl experienced the worst nuclear power plant disaster in history 24 years ago. Now with the use of DNA sequences, scientists studying different species in this area have been able to determine which are more vulnerable and more likely to be damaged by radiation at this level. 

The study was led by Professor Tim Mousseau from the University of South Carolina and Dr. Anders Moller from the National Centre for Scientific Research in Paris. They've worked in Chernobyl for more than 10 years gathering data, but also used existing databases to analyze DNA patterns for this particular study. 

The Chernobyl disaster occurred on April 26, 1986 when reactor number four ruptured and exploded due to rapid growths of power output. Radiation has contaminated the area ever since, dubbing this part of Chernobyl the "zone of alienation." 

Through the use of DNA sequences, scientists have been able to figure out which populations of birds, mammals and insects, who live in the zone of alienation, have been affected the most. DNA is a key factor in determining this because a species' DNA changes from generation to generation due to a "natural balance" between mutations and an individual's ability to fix damaged DNA. This is what allows species to evolve, and by looking at the substitution rate (the rate at which the DNA code is replaced by another), scientists are able to observe DNA sequences and predict which species have been affected the most (they can also determine if they will decline or become extinct). 

"This information is available in large database," said Mousseau. "So you can get the DNA sequences [of each species] and examine the changes that have occurred among a species over time. 

"What we have discovered is that when we look at the species in Chernobyl, we can predict, based on their substitution rates, which ones are most vulnerable to contaminants."

According to the results of this study, brightly colored birds and birds who travel long distances to migrate are the most vulnerable to radioactive contamination. A reason for this, according to Mousseau, could be that these birds have weaker DNA repair mechanisms. 

Evolutionary Biologist Louise Johnson from the University of Reading noted that these results were "fascinating" and that it has potential to test certain predictions about evolution.

"One of the difficulties of such research is that it isn't really an experiment - it is impossible to control for all of the confounding variables," said Johnson. "But [the scientists] have been very careful to test all of the other factors that could be important - antioxidants, population size, body size, etc. of bird species and it appears...that there is a shared casual relationship between accumulating mutations over time and the ability to withstand radiation."

This study was published in the Journal of Evolutionary Biology.