Sex on Six Legs_ Lessons on Life, Love, and Language From the Insect World - Marlene Zuk [25]
Of course, the first step after sequencing is to find genes with particular functions. Once that is accomplished, the opportunity arises for new, and sometimes diabolical, methods of pest control. Scientists are currently trying to use genetics to make insects pass on the instruments of their own destruction. A gene that is innocuous in the presence of, say, a particular antibiotic, but lethal otherwise, is inserted into an insect. The insect is then reared on a diet containing the antibiotic until it is an adult, when it no longer feeds, and is released into the wild. After the insects with the manipulated genes mate with normal members of the opposite sex, they produce offspring containing the gene—but those offspring are out in nature, where the lethal gene takes effect. Other even more clever methods are in the works.
As with genome size, studies of genome sequences confirm the presence of a hefty amount of noncoding DNA. One researcher refers to it as "dark matter," similar to the science fiction-like invisible stuff of outer space, which conveys both the mysterious nature of the substance and the almost peevish response that its discovery has elicited. We all seemed to have expected Mother Nature to be more thrifty in her allocation of genetic material, maybe saving that extra DNA, like leftovers at dinner. Shouldn't somebody have made another organism out of those bits and pieces of adenine and cytosine? Or maybe we just don't like the idea that it doesn't take many genes to make a whole complicated being; as Ryan Gregory says, "The strikingly low number of genes required to construct even the most complex organism represents one of the most surprising findings to emerge from the analysis of complete genome sequences." Somehow we seem to feel cheated by our own simplicity.
Of course, it's not that we are simple, per se. It's just that, once again, we are reminded that evolution is a tinkerer, using what's at hand to make its products. I like to think of the nuclei of our cells, not as perfectly tuned whirring machines, each gear essential, but as vast echoing warehouses of factories. Entire machines are outdated and useless, left rusted in a corner but never taken away and demolished. Others are jury-rigged out of pieces from older models and newer ones, rattling jerkily through their paces but ultimately manufacturing something useable.
The Social Genome
ALTHOUGH honeybees, like mosquitoes, are enormously important to human well-being, the sequencing of the honeybee genome was heralded not just because it might help us fight the mysterious decline of colonies throughout North America, but because bees are such extraordinarily social animals. Gene Robinson, who eschewed fruit-picking to devote himself to bees, thinks studying their genomes can show us how animals can become so integrated that they are often described as a single superorganism. According to the great biologist and ant lover E. O. Wilson, "If Earth's social organisms are scored by complexity of communication, division of labour, and intensity of group integration, three pinnacles of evolution stand out: humanity, the jellyfish-like siphonophores [creatures such as the Portuguese Man o' War], and a select assemblage of social insect species." Where does this high degree of interdependence come from?
One of the most surprising pieces of news from the honeybee genome project, published in 2006, was the relative paucity of genes associated with defense against diseases, compared with