Further probings revealed the existence of a clutch of master control genes, each directing the development of a section of body, which were dubbed homeotic (from a Greek word meaning ‘similar’) or hox genes.

The origin of the Tibetan dzong is not known although there is evidence of Chinese and Mongol influences in the style of their military architecture.

Terrell quipped to the new tactical officer, “He also holds doctorates in archaeology and xenobotany. So, if you get the urge to debate him about fossils or flowers . . . don't.”

The citadel walls that crown the hill, on the slopes of which the modern city descends amphitheatrically into the sea, are remnants of Venetian fortifications.