In many social insect species including ants, individuals show dramatic morphological, physiological, and behavioral specialization to their roles. To help understand the molecular mechanisms behind these characteristics, we developed a normalized EST library of 22,560 clones for the fire ant Solenopsis invicta. They were partially sequenced and assembled into 11,934 putatively different transcripts. Here, we describe an ongoing effort to characterize these sequences using bioinformatic annotation and comparative genomic tools.

We found that 3950 of our ant transcripts showed significant homology to the nr database of known genes. Among our ant transcripts, 652 were homologous to functionally annotated genes, encompassing a broad range of molecular functions and biological processes. However, 54% of our putative transcripts did not show homology to known genes. Through stringent comparison of these sequences with the genome of another social Hymenoptera, the honeybee, we identified 17 potentially Hymenoptera-specific sequences. Additionally, preliminary analysis indicates that more than 10 gene families have undergone lineage-specific expansion in ants.