Consortium decodes honey bee genome

HOUSTON -- (October 25, 2006) -- The Honey Bee Genome Sequencing Project Consortium, led by the Human Genome Sequencing Center at Baylor College of Medicine in Houston, announced today the generation and analysis of the genome sequence of the honey bee, Apis mellifera.

The primary results are presented in today’s issue of Nature, and over 40 companion manuscripts describing further detailed analyses are contained in current issues of Insect Molecular Biology, Genome Research, Science, Proceedings of the National Academy of Sciences (USA), and other journals.

The high quality draft sequence covers over 98 percent of the genome.

The BCM-HGSC generated the sequence data for the HBGSP. After assembly of the genome at the BCM-HGSC, the genome center led an analysis team of over 170 investigators representing nearly 100 groups from 16 countries. Funding for the HBGSP was largely provided by the National Human Genome Research Institute of the National Institutes of Health with additional funding provided by the U.S. Department of Agriculture.

“Comparing the genomes of the honey bee and other species separated over evolutionary time from humans have provided us with powerful insights into the complex biological processes that have evolved over hundreds of millions of years,” said NHGRI Director Dr. Francis S. Collins. “The genome of the honey bee has been added to a growing list of organisms whose sequence can be compared side by side to better understand the structure and functions of our own genes. And that will help speed our understanding of how genes contribute to health and what goes wrong in illness.”

The honey bee has long been treasured by man for its honey and wax and was domesticated in the Stone Age over 8,000 years ago. Bees were carried around the world with human migrations and were introduced into America from Europe in the 17th century. They perform a crucial service in agriculture by pollinating flowers.

“This represents a major advance in our efforts to guarantee pollination of the world’s food, fiber, and oilseed crops,” said USDA program leader Dr. Kevin J. Hackett. “Three-quarters of the world’s flowering plants are dependent on pollinators, yet the world’s principal pollinator, the honey bee, is in decline. Now scientists have a powerful tool for fighting back against the causes of decline, while improving bee health and increasing honey production.”

The honey bee is an important model for social behavior with its striking development into queen and worker castes, each consisting of a different type of organism yet all having the same genome, and elaborate social organization in the hive. Honey bees communicate with the famous “dance language,” and have sophisticated cognitive abilities.

“The sequencing of the first social insect is a landmark in taking behavioral research to the genomic level,” said Dr. George Weinstock, co-director of the BCM-HGSC. “The observation that the honey bee brain has a similar genetic parts list to a solitary insect like the fruit fly supports the concept that regulation of gene activity is an important key to behavior. In fact, our analysis did show potential regulators that were caste- and stage-specific.”

The honey bee is a member of the insect order Hymenoptera which includes hundreds of thousands of other species including ants, wasps, and sawflies. Honey bees diverged from fruit flies and mosquitoes, other insects that have been sequenced, over 300 million years ago. The honey bee genome fills an evolutionary gap in the growing collection of sequenced insects, and comparison between these insect genomes was an important part of the analysis. The honey bee has many vertebrate genes not previously found in sequenced insect genomes, thus revealing that these are not recent vertebrate innovations, but they are ancient genes from the 600 million-year-old last common ancestor of bees and vertebrates. Their absence in other insects is a reflection of evolutionary specialization in the different insect lineages.

The honey bee genome is quite distinct from other sequenced insects due to the long evolutionary distance between them. The genome is 50 percent larger than fruit flies but contains roughly the same number of genes. It has more regions rich in the adenine and thymine bases, and these often contain genes. In contrast, stretches of low AT content are often gene deserts. There are few transposon or retroposon families represented in the genome, another unusual characteristic compared to other insects.

“The honey bee genome sequence will aid genetic research into host-pathogen interactions,” said Dr. Kim Worley, associate professor of the BCM-HGSC. “There are striking differences between the immune system gene complements of honey bees and other sequenced insects.”

The project also identified a number of single nucleotide polymorphisms, SNPs, between the sequenced species and other honey bee species including the famous Africanized “killer” bee. Population genetic studies using these new genetic markers suggested that the genus Apis originated in Africa and migrated on multiple occasions into Eurasia. Insights into the invasion of the New World by African bees included demonstration of genetic mixing between pre-existing and Africanized bees.

“The genome sequence opens the door to a new era in honey bee genetics,” said Dr. Richard Gibbs, director of the BCM-HGSC.

The honey bee project is one of five insect genomes the BCM-HGSC has undertaken, including the fruit fly, wasp, pea aphid, and red flour beetle. The BCM-HGSC was one of five centers in the public Human Genome Project, and has since completed or is working on genomes of four non-human primates, nine other mammals, the sea urchin, and numerous microbes in addition to the insect genomes. Other projects at the BCM-HGSC are studying the genetic basis of human disease and this will be the major emphasis of future work.