- Author: Kathy Keatley Garvey
But if you're UC Davis entomologist-geneticist Geoffrey Attardo, you do.
He led landmark research published Sept. 2 in the journal Genome Biology that provides new insight into the genomics of the tsetse fly, an insect that transmits the parasite that causes human and animal trypanosomiasis. In humans, it's commonly known as sleeping sickness, and if not treated, it's fatal.
Tsetse flies, Glossina sp., are of great medical and economic importance, wrote Attardo and co-authors Adly M. M. Abd-Alla of the Insect Pest Control Laboratory, Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria, and Serap Aksoy of the Yale School of Public Health, New Haven, Conn. They related that since the implementation of surveillance and record-keeping in the 20th century, “millions of people in sub-Saharan Africa” have died from sleeping sickness.
Their research compares and analyzes the genomes of six species of tsetse flies and could lead to better insights into disease prevention and control. “It was a behemoth project, spanning six to seven years,” said Attardo, an assistant professor in the Department of Entomology and Nematology. “This project represents the combined efforts of a consortium of 56 researchers throughout the United States, Europe, Africa and China.”
“The aim of these studies,” the authors wrote, “was to generate and mine the genomic sequences of six species of tsetse flies with different ecological niches, host preferences, and vectorial capacities. The goals of the analyses performed here are to identify the novel genetic features specific to tsetse flies and to characterize the differences between the Glossina species to correlate the genetic changes with phenotypic differences in these divergent species.”
“Expanded genomic discoveries reveal the genetics underlying Glossina biology and provide a rich body of knowledge for basic science and disease control,” the scientists concluded. “They also provide insight into the evolutionary biology underlying novel adaptations and are relevant to applied aspects of vector control such as trap design and discovery of novel pest and disease control strategies.”
Attardo, who joined the UC Davis faculty in 2017 after serving 13 years with the Yale School of Public Health, said the massive research project involved “the complete sequencing and assembly of six Glossina species, including the two primary vectors of human African tryapnosomiasis, three major vectors of animal trypanosomiasis and one ancestral tsetse species which demonstrates some resistance to the species of trypanosomes responsible for human and some animal forms of the disease.”
- A clearer definition of the Glossina phylogenetic tree and placement of a controversial species.
- Identification of rapidly evolving regions of the tsetse genome relative to Drosophila.
- Identification of Glossina specific genes and their functions as well as expansions and contractions of gene families in tsetse relative to other flies.
“We discuss the functional implications of these changes and how they relate to tsetses' physiological adaptations and evolutionary history,” Attardo noted.
“We discovered that the rhodopsin gene family which is associated with vision/color detection shows conservation in motion detection and tracking associated genes.” Attardo said. “However, the gene coding for the protein that detects blue wavelengths is divergent relative to houseflies and shows the highest variance between Glossina species of all the rhodopsin genes. This is significant as the color blue is used as an attractant to bring tsetse into the traps used for control. It suggests that different species may be tuned/attracted to different wavelengths of blue.”
They also analyzed the genes associated with tsetse immunity and the relative differences in comparison with houseflies and fruit flies. “We see many immune genes missing in Glossina and increased copy numbers of genes associated with negative regulation of immune function. We think this may be associated with the evolution of obligate symbiosis as a way to protect their symbionts.”
“We also found extreme conservation of milk proteins between all sequenced species,” the UC Davis medical entomologist said. “On the flip side, male reproductive proteins (seminal proteins) appear to be very rapidly evolving relative to the rest of the genome. The copy numbers of these genes also change significantly between species.”
The scientists also found an overall reduction of olfactory associated genes and protein modifications specific to salivary proteins in the two species that vector human trypanosomiasis.
In 1995, the World Health Organization (WHO) estimated that 60 million people were at risk of sleeping sickness, with an estimated 300,000 new cases per year in Africa, and fewer than 30,000 cases diagnosed and treated. Due to increased control, only 3796 cases were reported in 2014, with less than 15,000 estimated cases, according to WHO statistics.
The parasitic disease “mostly affects poor populations living in remote rural areas of Africa,” according to WHO. “Untreated, it is usually fatal. Travelers also risk becoming infected if they venture through regions where the insect is common. Generally, the disease is not found in urban areas, although cases have been reported in suburban areas of big cities in some disease endemic countries.”
Several National Institutes of Health (NIH) grants, awarded to Attardo and Aksoy, funded the research. They also drew funding from the McDonnell Genome Institute at Washington University School of Medicine; the National Research Foundation, the Swiss National Science Foundation, and the Slovak Research and Development Agency.
- Author: Kathy Keatley Garvey
It's August, 2007 and bee breeder-geneticist Susan Cobey, manager of the Harry H. Laidlaw Jr. Honey Bee Research Facility, University of California, Davis, is opening a hive in the apiary.
"Girls, where's your mother?” she asks again, pulling out another frame.
She quickly locates the queen bee, "the mother of them all." And "all" is not right in the bee world.
Susan "Sue" Cobey wants to "build a better bee."
Cobey, now a bee breeder-geneticist at Washington State University, seeks to maximize the good traits and minimize the bad traits. By controlling the genetics of honey bees (Apis mellifera), she says, researchers can breed stronger, more survivable bees--bees able to withstand such pests as varroa mites and such maladies as colony collapse disorder. “Controlled mating is the basic foundation of all stock improvement programs.”
Cobey who joined Washington State University's Department of Entomology in 2010, works with department chair and bee scientist Walter "Steve" Sheppard, who researches population genetics and evolution of honey bees, insect introductions and mechanisms of genetic differentiation; and bee scientist Brandon Hopkins, an expert on cryopreservation of bee semen.
"Building a better bee” involves collecting bee semen (germplasm) in European countries, including Italy, Slovenia, Germany, and the Republic of Kazakhstan. Those countries, she points out, rear bees with favorable genetic traits, such as resistance to varroa mites, the No. 1 enemy of beekeepers in the United States.
The dwindling gene pool diversity in the United States is troublesome, Cobey says. Although European colonists brought honey bees to the Jamestown colony in 1622, live honey bee imports have been banned in the United States since 1922.
So Cobey has been traveling to Europe since 2006--every year but 2016--to collect bee semen. “It took me 22 years to get that first permit," says Cobey. "It was opening the Canadian border to Europe that turned it--politics, not biology-based. We started asking (to collect bee semen in Europe) in the early 1980s with Harry Laidlaw's backing."
"My first trip to Europe was in 2006 from Ohio State University for carnica (Apis mellifera carnica, a darker subspecies) bee stock," recalled Cobey, who studied and trained with Harry Laidlaw, the father of honey bee genetics. Cobey joined the UC Davis Department of Entomology in 2007 and a year later, she began collecting bee semen in Europe with Steve Sheppard. The WSU bee breeding program involves crossbreeding honey bees to bolster their genetic traits. WSU is the only lab in the country with permits to import bee semen, and the only laboratory with the ability to freeze it. The WSU team uses liquid nitrogen to preserve the bee semen.
The European trip was memorable and productive. "Slovenia is a beautiful country with a long tradition of beekeeping," Cobey said.
"In Semič, Slovenia, we collected bee semen, met with the local beekeepers and gave presentations about our program,” Cobey said. “Afterwards we celebrated with a feast of roasted pig, hosted by Stane Plut."
"What a trip that was (to Italy and Slovenia)!" said Park-Burris. "Slovenia only allows the beekeepers to keep Carniolan bees. Sue was in heaven and it was fun to see how excited she got about her bees. Likewise I was really happy to see the Italy stock in Bologna again. The beekeepers there were so excited that we wanted more of their stock. Their hospitality was overwhelming."
Park-Burris marveled that the Slovenians keep almost all of their hives in "houses" and "then they paint pictures on them that tell a story. It was very interesting. One Slovenian told me that they treat their bees like pets and that was so true!"
Cobey is an international authority on the instrumental insemination of queen bees. She's taught the specialized technique for more than three decades, instructing students how to extract semen from a drone, and inseminate an anesthetized virgin queen. Magnified images on a computer screen help illustrate the procedure.
Cobey began training students in instrumental insemination in 1984. "This has taken me all over the world--currently I have invitations/inquiries to six countries," said Cobey, who has set up a lab at her home on Whidbey Island to teach workshops. Husband Timothy Lawrence, also a veteran beekeeper, is an associate professor and the county director (Island County) of Washington State University Extension.
"I receive three to five requests for classes per day here; I'm sorting these to the most needed/most serious," Cobey said. "The interest is much more serious. But note--still many struggle with this, as there are many aspects, including the specialized beekeeping that goes with it."
Cobey recently taught UC Davis staff research associates and beekeepers Bernardo Niño and Charley Nye of the Elina Lastro Niño lab in a three-day class in her lab. "I'm just doing small classes so I can give more individual attention, and concentrate on the details. So I have just three or four people per class. I hope UC Davis starts some classes as the interest is overwhelming." A UC Davis goal is to offer classes in 2018 or 2019, according to Niño.
Some of Cobey's students go on to teach others the technique. UC Davis graduate Elizabeth Frost learned from Susan Cobey while working as her staff research associate at the Laidlaw facility. "She is now teaching instrumental insemination in Australia," Cobey said.
Cobey traces her interest in bees back to the 1970s. After enrolling in a student exchange program in entomology in 1975 at Oregon State University, Corvallis, she received her bachelor's degree in entomology in 1976 from the University of Delaware, Newark. From 1978 to 1980, she worked at UC Davis, where she was influenced by Harry Laidlaw (1907-2003).
Laidlaw perfected artificial bee insemination technology. “He discovered the valve fold in the queen bee which hinders injection of semen into the lateral oviducts,” Cobey said. “He developed instrumentation to bypass the valve fold enabling the success of bee insemination.”
Utilizing the training, Cobey established the Vaca Valley Apiaries in Vacaville in 1982, developing the highly regarded New World Carniolan Breeding Program. The Carniolans, originally from the Austrian Alps and the Balkans, are darker than the popular Italian honey bees, the most common subspecies in the United States. The Carniolans are known for their gentle behavior, and may be more suited to cooler weather.
In 1990 Cobey pulled up roots—and hives—and settled in Ohio, serving as staff apiarist at the Rothenbuhler Honey Bee Research Laboratory at Ohio State University until accepting the staff research associate position and manager of the UC Davis facility in 2007.
Now she's focused on the WSU bee breeding program, which produces breeder queen bees, which are then provided to commercial queen bee producers, who in turn can produce thousands of queen bees for the nation's beekeepers. The goal is to preserve and improve the stock of honeybees and to prevent subspecies from extinction.
Hopkins says that genetic diversity offers improved bee fitness and productivity. A genetically diverse colony handles diseases better. The biggest need in the U.S. honey bee population is anything that would increase resistance to parasitic Varroa mites, Hopkins says. (See WSU post.)
Cobey is featured in a National Public Radio piece, "No Offense, American Bees, But Your Sperm Isn't Cutting It."
"Honey bees aren't native to America," Cobey told reporter Ryan Bell. "We brought them here. But the U.S. closed its borders to live honey bee imports in 1922, and our honey bee population has been interbreeding ever since."
"Girls, where's your mother?"