Smithsonian researchers map genome of Hawaiian bird
Imagine a jigsaw puzzle with 100 million pieces and multiple copies of each individual piece. Now, imagine trying to match the identical pieces to form one complete image.
That is how Smithsonian Conservation Biology Institute researcher Robert Fleischer describes the process of mapping a genome.
Fleischer, the institute’s head of the Center for Conservation and Evolutionary Genetics, was part of a research team that recently completed mapping the genome for the Hawaiian honeycreeper.
A news release issued by the institute notes this is the first time that researchers from the institute in Front Royal have mapped the genome of any avian species.
According to the Genetics Home Reference, a genome is essentially “an organism’s complete set of DNA” or “the information needed to build and maintain that organism.”
The purpose of mapping this particular genome, Fleischer said, is to conserve the remaining species of honeycreepers by studying the effects of a non-native avian malaria.
Mapping this genome was a major step in a complicated research project that is working toward finding a solution, Fleischer said.
He explained that this particular family of birds has seen a “progressive extinction” since the Polynesians arrived on the islands between 1000 and 1200 A.D.
In that time, the amount of diverse honeycreeper species has decreased through various causes from just over 30 to about 18 today.
Fleischer explained this research group has mapped the genome of a particular species of honeycreeper called the amakihi.
He said this species lives in low elevation areas of Hawaii — where malaria and the transmitting mosquitoes are prevalent — and “seems to tolerate” the disease.
Fleischer said the disease “affects many of the species” and the highly susceptible honeycreepers typically reside in points of high elevation where malaria and mosquitoes are rare.
“If you take a high-elevation [honeycreeper] that’s never been around malaria … and infect them with it, about 60 percent of them die,” Fleischer said.
For this particular study, Fleischer said that he and his team are “interested in the ones that survive versus the ones that die and how they differ genetically.”
He said one of the next steps after this genome mapping is to perform a “gene expression” analysis. Essentially, this will tell the team what genes are involved in the survival of the amakihi.
They will take the current genome sequence and screen it against the genes of randomly selected amakihi. This process will apply to 140 different amakihi living in various parts of the island as well as “old museum specimens” of extinct honeycreepers.
The hope from using all of these methods, Fleischer said, is to “pinpoint the gene or genes … that are involved in the amakihi’s ability to tolerate the malaria.”
“That might lead to developing some vaccine or chemical treatment to provide when we do captive breeding,” Fleischer said.
At the same time, Fleischer stressed that time is a factor with this research effort.
The mosquitoes responsible for spreading malaria are beginning to migrate toward higher elevations as the Hawaiian Islands heat up due to climate change, Fleischer said.
As the mosquitoes progress up the mountains, it could cause the residing range of certain highly susceptible honeycreepers to shrink to the point that they “might not have any refuge.”
“We figure there is a limited amount of time before we lose another 10 or 12 species of honeycreepers,” Fleischer said.
He noted that researchers at the University of Wisconsin have roughly estimated that it could take 50 years before the mosquitoes completely advance up the mountains.
However, because the malaria is being spread through one type of mosquito and parasite, Fleischer said that makes creating any kind of vaccine simpler.
Compared with human malaria, Fleischer said the avian malaria has “very little genetic diversity.”
Because of this, Fleischer said, “We may be able to combat this better than human malaria.”
At the moment, Fleischer said they have another genome happening where they are using this recently assembled genome to analyze 140 individual amakihi from various parts of the islands.
Fleischer said that he and his group “have to get the genome, the sequences from these other individuals and make the right kind of comparisons and locate the genes.”
“Once we have that, then we can try to look into ways to solve the problem,” Fleischer said.
Contact staff writer Kevin Green at 540-465-5137 ext. 155, or email@example.com
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