Humans started farming about 10,000 years ago. But we are not the only ones who have adopted an agricultural way of life. The Panamanian leaf-cutting ants (Acromyrmex echinatior), which was discovered in some parts of America 15 years ago, also exhibit a similar farming behavior with fungus. These ants break down the leaves into mulch which help fungus grow special structures that will be consumed by ant colonies. Sanne Nygaard of the Copenhagen Centre for Social Evolution and colleagues have sequenced the genome of this ant and revealed clues to the evolution of fungus farming behavior.

One of the most interesting findings in the genome of the leaf-cutting ants was that there are more genes in two particularly remarkable gene families. "Based on their function in other organisms, we expect them to be involved in mating system adaptations and symbiotic food processing with the fungus," said Nygaard. He explained that these findings are exciting because the evolutionary changes in the reproductive biology and farming lifestyle of these ants can now be associated with specific genomic characteristics.

The research article is available at http://genome.cshlp.org/content/early/2011/06/27/gr.121392.111.full.pdf+html.