Perhaps It's a Display of Gratitude for the Hospitality

Over at Small Things Considered, Moselio Schaechter and Merry Youle have a post considering Wolbachia endosymbionts and the jumping genes they deliver to host genomes. Referring to a study published last year, they write, "In the tropical fruit fly, Drosophila ananassae, virtually the entire Wolbachia genome had been transferred." But the host's genome defense is generally good, so transferred genes tend not to be transcribed or used -- which has the bloggers wondering why this happens at all. "Are the Wolbachia squirreling away their genes for safekeeping, or is there some other reason for their massive transfer to the host's nucleus? A mystery," they add.