Hot on the Trail of Bacteria


Recent developments in the research study being carried on by Albert Bennett, dean of the School of Biological Sciences; Brandon Gaut, chair of the Department of Ecology and Evolutionary Biology; and Anthony Long, Professor of Ecology and Evolutionary Biology have found that bacteria can be resourceful for survival. The teams of researchers have published in the esteemed Science magazine, highlighting the potential benefits for society in the development of new biofuels or possible methods of environmental cleanup.


Through increasing the amount of heat affecting the E. coli bacteria, the researchers were able to determine that there are two pathways in particular that the populations could have taken in order to survive by the strong relationship between the genetic modifications within each pathway displaying a pattern.


The findings showed 1,331 genetic mutations in the bacterial DNA seen in more than 600 various sites. Over the course of a year, these bacteria populations expanded to approximately 2,000 generations under the condition of increased heat.


“The real question that motivates all of this is: Is evolution predictable?” said Professor Bennet. “If you put organisms in a new environment, can you predict how it will change?”


In order to test adaptations on a large and efficient scale, the team chose to work with E. coli bacteria, allowing them to cultivate samples over the span of 2,000 generations and track their adaptations through temperature changes.


After 2,000 generations, they compared the lines of E. coli to their ancestor, which resulted in significantly better growth, approximately 30 percent, of the new lines in 42.2 degrees Celsius.


“We were able to look at these results and notice the genetic mutations taking place allowing these lines to adapt to the increase in temperature,” Professor Gaut said. “Because we were able to replicate this type of evolution in a bigger way, we are able to conclusively prove the adaptive qualities of bacteria over the course of 2,000 generations, 40,000 human years.”


Professor Bennett had done a similar type of experiment prior to this but on a much smaller scale, resulting in only six lines with which the team could not conclusively prove their hypothesis regarding adaptation in evolution. After they looked further into their results, they found 115 gene sequences with two more predominant ones that accounted for about 95 lines and the remaining lines took various pathways.


Professor Bennett analogizes the process to climbing a mountain.


“When mountain climbers make their way up the mountain they take various pathways. I mean, there may be a few main ways and roads many of them take ,but there are so many more diverse outcomes possible,” he said.


The basic concepts used in their complicated evolutionary experiment can be expanded for other usages. Potentially, one could test bacteria to see which could survive in environmental pollutants.


“Then you could hypothetically look into which lines not only survived but were able to use the environmental pollutant as fuel and ingest it,” said Gaut.


This could possibly lead to the cultivating of adapted bacteria to clean up oil spills and more. Thus, with more of such experiments, they can test what has always been theorized regarding evolutions and present concrete data with significant numbers proving various adaptation hypotheses.


“Though we are using bacteria and it is a much smaller organism, the idea behind the experiment is much larger and can be essentially utilized across the board to test the evolutionary concepts already accepted,” Gaut said. “It’s about the bigger picture.”