Gene expression levels in fire ants

Analysis of gene expression levels in workers, queens and males of the fire ants S. invicta, S. richteri and their hybrids, at the larval, pupal and adult stages (see also Ometto et al. 2011 Mol Biol Evol 28:1381–1392). Samples were collected in the field in 2005 and 2007. All collected colonies were returned to the laboratory and maintained in a rearing room under standard conditions. Gene expression of each sample (n=140) was measured through microarray hybridizations. Next, we estimated the relative expression of each clone for each node (caste/species/stage; n = 27), and the significance of the differential expression of such clones among nodes, using the Bayesian approach implemented in the program Bayesian Analysis of Gene Expression Levels (BAGEL; Meiklejohn and Townsend 2006 Brief Bioinformatics 6:318–330). Three-letter labels (one for each node) identify species (i = S. invicta; r = S. richteri; h = S. invicta X S. richteri), caste (W = workers; Q = queens; M = males), and developmental stage (l = larvae; p = pupae; a = adults).