Effect of time on colony odour stability in the ant Formica exsecta.

Among social insects, maintaining a distinct colony profile allows individuals to distinguish easily between nest mates and non-nest mates. In ants, colony-specific profiles can be encoded within their cuticular hydrocarbons, and these are influenced by both environmental and genetic factors. Using nine monogynous Formica exsecta ant colonies, we studied the stability of their colony-specific profiles at eight time points over a 4-year period. We found no significant directional change in any colony profile, suggesting that genetic factors are maintaining this stability. However, there were significant short-term effects of season that affected all colony profiles in the same direction. Despite these temporal changes, no significant change in the profile variation within colonies was detected: each colony's profile responded in similar manner between seasons, with nest mates maintaining closely similar profiles, distinct from other colonies. These findings imply that genetic factors may help maintain the long-term stability of colony profile, but environmental factors can influence the profiles over shorter time periods. However, environmental factors do not contribute significantly to the maintenance of diversity among colonies, since all colonies were affected in a similar way.

Characterization of a chromosomally complex lung cancer cell line using multiwell fluorescence in situ hybridization.

The chromosomal characterization of a non-small cell lung cancer cell line (NCIH358) is described. This characterization was achieved using a simple, cheap and technically straightforward multiwell fluorescence in situ hybridization (FISH) method. The many and complex chromosome rearrangements identified by this method could not be defined using conventional G-banded chromosome analysis, and have not been previously described. For the detailed characterization of complex cell lines, multiwell FISH has many advantages over more technically demanding and expensive FISH techniques, and opens up the possibility of screening for consistent rearrangements, leading to the identification of unique fusion genes.