Scientists sequence ant genomes first time

US scientists said Friday they have mapped the entire genome sequences of two different species of ants for the first time, potentially providing insight into human aging and behavior.

“Ants are extremely social creatures and their ability to survive depends on their community in a very similar way to humans,” said research project leader Danny Reinberg, a professor of biochemistry at New York University Langone.

“Whether they are workers, soldiers or queens, ants seem to be a perfect fit to study whether epigenetics influences behavior and aging.”

Epigenetics is the study of how genes are activated or deactivated in response to changes in conditions rather than changes to DNA sequences, and helps determine inherited changes in an organism’s traits or gene expression.

NYU Langone Medical Center scientists collaborated with colleagues in Pennsylvania, Arizona and China starting in 2008 to study the epigenetic differences between Jerdon’s jumping ant and the Florida carpenter ant to link them to processes in other animals, including humans. After the project was completed, ants became the second family of social insects whose genome was sequenced, after the honey bee.

The study, published in the journal Science, focused on the role of epigenetics on longevity in ant colonies where the queens can live up to 10 times longer — several years — than worker ants, whose lifespan ranges between three weeks and a year.

In comparing the Jerdon’s jumping ant to the Florida carpenter ant, a destructive pest in the southeastern United States, the scientists found that about 20 percent of their genes are unique, while about 33 percent are shared with humans.

“In studying the genomes of these two ants, we were fascinated by the different behaviors and different roles that the worker ants develop,” said Reinberg.

“Since every ant in the colony starts with the same genetic information, the different neuronal connections that specify the behavior appropriate for each social rank must be controlled by epigenetic mechanisms,” he said.

“The findings could potentially help us learn more about the effect of epigenetics on brain function in humans.” When the jumping ant queen dies, workers in the small colony fight until only a few remain and become new queens, or gamergates, which live longer than worker ants.

The scientists found that these replacement queens had an over-expression of proteins linked to longevity, including the enzyme telomerase. They also had a large amount of small RNAs, a type of genetic material that finesses gene expression in humans and other organisms.

Among carpenter ants, only the queen lays fertilized eggs and her death also spells the end of the colony. Under these ants’ far more sophisticated caste system and social organization, non-reproductive ants belong to the major or minor workers’ caste.

Major workers are tasked with protecting the colony, while minor workers search for food. The scientists said that epigenetics determine how their brains are wired differently for their particular tasks.

Reinberg and his team found important differences in how genes functioning in the brain are expressed, thus helping explain the role of genes in influencing ant behavior.

AFP