Epigenetics Books

“Ants have a powerful caste system. A colony typically contains ants that carry out radically different roles and have markedly different body structures and behaviors. These roles, Reinberg learned, are often determined not by genes but by signals from the physical and social environment. 'Sibling ants, in their larval stage, become segregated into the different types based on environmental signals,' he said. 'Their genomes are nearly identical, but the way the genes are used—turned on or off, and kept on or off—must determine what an ant "becomes." It seemed like a perfect system to study epigenetics. And so Shelley and I caught a flight to Arizona to see Jürgen Liebig, the ant biologist, in his lab.'

The collaboration between Reinberg, Berger, and Liebig has been explosively successful—the sort of scientific story ('two epigeneticists walk into a bar and meet an entomologist') that works its way into a legend. Carpenter ants, one of the species studied by the team, have elaborate social structures, with queens (bullet-size, fertile, winged), majors (bean-size soldiers who guard the colony but rarely leave it), and minors (nimble, grain-size, perpetually moving foragers). In a recent, revelatory study, researchers in Berger’s lab injected a single dose of a histone-altering chemical into the brains of major ants. Remarkably, their identities changed; caste was recast. The major ants wandered away from the colony and began to forage for food. The guards turned into scouts. Yet the caste switch could occur only if the chemical was injected during a vulnerable period in the ants’ development.

[...] The impact of the histone-altering experiment sank in as I left Reinberg’s lab and dodged into the subway. [...] All of an ant’s possible selves are inscribed in its genome. Epigenetic signals conceal some of these selves and reveal others, coiling some, uncoiling others. The ant chooses a life between its genes and its epigenes—inhabiting one self among its incipient selves.”
― Siddhartha Mukherjee