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To sequence the human genome, scientists established a network of laboratories, equipped with robots that could analyze DNA day and night. Once they began to finish up the human genome a few years ago, they began to wonder what species to sequence next. With millions of species to choose from, they could only pick a handful that would give the biggest bang for the buck. Squabbling ensued, with different coalitions of scientists lobbied for different species. Some argued successfully for medically important species, such as the mosquito that carries malaria. Others made the case for chimpanzees, to help them pinpoint that genes that make us uniquely human. And in 2002, a team of scientists made the case for the humble honeybee.
Why spend millions on the honeybee? For one thing, honeybees are commercially valuable. They make honey, and they pollinate crops. But the honeybee lobby also argued that there were much deeper reasons to sequence its genome. Honeybees lives in societies that rival our own in size and complexity. A single hive may contain as many as 80,000 bees, which together build the hive, gather food, and feed the next generation of bees. They gather nectar from flowers, and they find flowers by merging many sources of information including the position of the sun and the subtle nuances of a flower's scent. When they come back to their hive, they waggle out a dance to indicate where other honeybees can find the flowers. They manage all this with only a million neurons in their head--a thousandth the number we have.
Only some of the bees in a hive search for food. Each hive is divided up into castes, such as foragers, sterile female worker bees who tend to the larvae, male drones who mate with the queen, and the queen herself. These different kinds of honeybees might well seem like they belong to different species. The queen lives ten times longer than her workers, churning out 2,000 eggs a day. Yet the genetic information for building all of these bees is stored in the same genome. Each bee's fate is determined as it develops. All bee larvae are initially fed a substance called royal jelly, secreted from the heads of the workers. It's a rich source of vitamins and other nutrients. It also influences how a bee develops. After three days, almost all the larvae get switched to a diet of honey. Only the queens in the making continue to get the royal jelly. Sequencing the honeybee genome could allow scientists to begin to piece together the way genes can help give rise to a complex animal society.
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