Bat DNA Analysis Provides Key Evolutionary Insights
December 21, 2012

Bat DNA Analysis Yields Insight Into Evolution Of Flight And Disease Resistance

Brett Smith for - Your Universe Online

A comparative genetic analysis of two distantly related bat species has revealed new insights into the evolutionary development of flight and disease resistance, according to a new report in the latest edition of the journal Science.

As the only mammals capable of sustained flight, bats are an anomaly in the animal world. They also have a predilection for transmitting diseases that do not appear to affect the animals themselves.

“Bats are a natural reservoir for several lethal viruses, such as Hendra, Ebola and SARS, but they often don´t succumb to disease from these viruses,” said study co-author Chris Cowled, a researcher from the Australian Animal Health Laboratory. “They´re also the only mammal that can fly, and they live a long time compared to animals similar in size.”

These unique capabilities inspired scientists from BGI in China, University of Copenhagen in Denmark, and several other institutions around the world to search for the genetic mechanisms behind the bats´ distinctive behaviors.

In the study, the international team conducted a genomic sequencing and analysis of two different wild bats, the large Black flying fox and the smaller David's Myotis.

Initial results of the sequencing analysis confirmed that two bat species share a common ancestor and are members of the clade of mammals know as Pegasoferae, which diverged from the horse genus Equus around 88 million years ago.

To recognize the genetic mechanisms that made the origin of flight possible in bats, researchers investigated the genes responsible for the recognition and repair of genetic damage. They found that these genes are responsible for minimizing or repairing the negative metabolic effects that are generated as a result of sustained flight. In addition, the geneticists also found unique flight-related genes from a common bat ancestor that are responsible for skin elasticity and muscle contraction.

The team also successfully identified genes associated with the unique immune system of bats. They found that some of these genes play a role in DNA damage response, which has an important function in host defense and is a known target for virus interaction. Researchers inferred that the immune system of bats has likely been influenced by the changes in DNA damage response mechanisms during selection for flight.

Researchers also identified genes that could be responsible for the differences in behavior between the two bat species, including their eating habits and echolocation abilities.

"The rapid development of genomics greatly enhances our understanding to the mysteries of evolutionary biology, such as the origin, differentiation, and species diversity," said Guojie Zhang, Project Manager from BGI. "These wonderfully diverse bats are in a special position in the evolutionary processes, and have some fascinating biological characteristics, including sustained flight, hibernation, echolocation, among others. Genomics is one of the approaches to conduct those studies.”

“I believe the data generated in the study will lay a solid foundation for the further functional research,” he added. “The genomic comparative analysis also will provide important tools for further understanding the autoimmune system of bats and the relevant defense mechanisms against viral infections."