|NHGRI Selects 13 More Organisms for
Gibbon, Bats, Finch and Mosquito Strains Added to
Bethesda, Maryland — The National Human
Genome Research Institute (NHGRI), one of the National Institutes
of Health (NIH),
announced today that the Large-Scale Sequencing Research
Network will target 13 more organisms as part of its
ongoing effort to produce genomic data that will expand
biological knowledge and improve human health.
The National Advisory Council for Human Genome Research
(NACHGR), which is a federally chartered committee that
advises NHGRI on program priorities and goals, recently
approved a comprehensive plan that adds two new sets
of sequencing targets. The strategy includes a mix of
whole genome sequencing, genome mapping and sequencing
of genomic regions chosen for their scientific merits.
“We want to set the stage for a greater understanding
of the major biological innovations that have occurred
throughout evolution, with emphasis on learning more
about our own genome. Genomic information from a wide
array of species already is proving useful in many areas
of biomedical research that may benefit both humans
and animals,” said Mark S. Guyer, Ph.D., director of
NHGRI’s Division of Extramural Research.
The first group of targets consists of nine mammals.
Eight mammals will be sequenced at low-density draft
coverage, created by sequencing their genomes two times
over. This sequencing strategy, begun last year on another
set of mammals, is used primarily to identify features
that are similar, or conserved, among the genomes of
the human and other mammals. Sequences that have been
conserved throughout evolution often reveal important
functional regions of the human genome. Initial data
show that using low-density sequencing for such comparisons
is almost as effective as more costly, high-density
sequencing. The eight mammals are: 13-lined ground squirrel
(Spermophilis tridecemlineatus), megabat (Cynopterus species),
microbat (Microchiroptera species), tree shrew
(Tupaia belangeri), bushbaby (Otolemur
garnetti), hyrax (Procavia capensis),
pangolin (Manis species) and sloth (Bradypus or Choloepus species).
The ninth mammal is the Northern white-cheeked gibbon
(Nomascus leucogenys). This non-human primate
species belongs to a major evolutionary branch that
has not yet had the genome of any of its members sequenced.
The gibbon genome is unique because it contains many
chromosomal rearrangements, which makes it valuable
for studying how such rearrangements have contributed
to the evolution and speciation of humans and other
non-human primates. To identify chromosomal rearrangements,
researchers will need to sequence only small portions
of the gibbon genome through a process known as Bacterial
Artificial Chromosome (BAC)-end sequencing.
Also selected in the latest round were four non-mammalian
organisms. Three of the organisms have been targeted
for six-fold, or “high-quality draft,” sequencing. They
are: M and S strains of a malaria-carrying mosquito
(Anopheles gambiae) and a roundworm (Heterorhabditis
bacteriophora). Researchers will also construct
a physical map of the zebra finch (Taeniopygia guttata)
genome, paving the way for later efforts to sequence
selected regions of the songbird’s genome.
“Sequencing the genomes of a diverse set of organisms
is a powerful tool to understand the biological processes
at work in human health and illness,” said NHGRI Director
Francis S. Collins, M.D., Ph.D. “Comparative genomics
has proven to be one of the most effective strategies
for revealing the important structural and functional
elements of the human genome sequence.”
The mosquito, Anopheles gambiae, is medically
significant because it can harbor the malaria parasite, Plasmodium
falciparum, and is the primary transmitter of the
disease in Africa. Approximately 30 of 500 Anopheles species
are known vectors of human malaria. Malaria afflicts
up to 300 million people and kills more than 1 million
people a year. In 2002, Celera Genomics completed a
draft genome sequence of a laboratory strain of Anopheles
gambiae, a hybrid of two naturally occurring species,
known as “M” and “S” strains, that can transmit malaria.
Researchers expect that sequencing the genomes of the
M and S strains, both of which are insecticide-resistant,
will help to further efforts to combat malaria. The
sequence data will also provide new insights into key
structural and functional elements of the Anopheles genome.
The roundworm genome is important because its sequence
will aid in comparative annotation of the genomes of
other roundworms that have been sequenced, including
that of Caenorhabditis elegans, one of the
most important model systems for understanding animal
development. In addition, Heterorhabditis bacteriophora is
widely used as a biological control agent because it
kills agricultural insect pests. Understanding its genome
will increase insights into biological control, as well
as into basic mechanisms of parasitism that may be applicable
to parasites of humans.
The zebra finch was chosen because it is a major model
system for understanding brain development, learning
and memory. Because it is related to the chicken, whose
genome has already been sequenced, it will be possible
to leverage the chicken genome to get more insight from
the zebra finch map.
It has been shown that most segments of the human genome
originated long before humans themselves. Consequently,
scientists will use the genome sequences of the non-mammalian
animals to learn more about how, when and why the genomes
of humans and other mammals came to be composed of certain
DNA sequences, as well as to gain new insights into
the organization of genomes.
Sequencing efforts will be carried out by the NHGRI-supported
Large-Scale Sequencing Research Network, which consists
of five centers: Agencourt Bioscience Corp., Beverly,
Mass.; Baylor College of Medicine, Houston; the Broad
Institute of MIT and Harvard, Cambridge, Mass.; The
J. Craig Venter Science Institute, Rockville, Md.; and
Washington University School of Medicine, St. Louis.
Assignment of each organism to a specific center or
centers will be determined at a later date.
NHGRI’s process for selecting sequencing targets begins
with two working groups comprised of experts from across
the research community. Each of the working groups is
responsible for developing a proposal for a set of genomes
to sequence that would advance knowledge in one of two
important scientific areas: understanding the human
genome and understanding the evolutionary biology of
genomes. A coordinating committee then reviews the working
groups’ proposals, helping to fine-tune the suggestions
and integrate them into an overarching set of scientific
priorities. The recommendations of the coordinating
committee are then reviewed and approved by NHGRI’s
advisory council, which in turn forwards its recommendations
regarding sequencing strategy to NHGRI leadership.
The genomes of a number of organisms have been or
are being sequenced by the large-scale sequencing capacity
developed by the Human Genome Project. These include
the dog, the mouse, the rat, the chicken, the honey
bee, ten fruit flies, the sea urchin, two puffer fish,
two sea squirts, two roundworms, over a dozen fungi,
baker’s yeast and the bacterium Escherichia coli. Organisms
currently in the NHGRI sequencing pipeline include:
macaque, orangutan, cow, platypus, red flour beetle,
several additional species of fungi and domestic cat.
A complete list of organisms and their sequencing status
can be viewed at www.genome.gov/10002154.
To learn more about the rapidly growing field of comparative
genomic analysis, go to: www.genome.gov/11509542.
For the white papers on other organisms currently in
NHGRI’s sequencing pipeline, go to: www.genome.gov/10002154.
For more on NHGRI’s selection process for large-scale
sequencing projects, go to: www.genome.gov/Sequencing/OrganismSelection.
High-resolution photos of the gibbon, bushbaby, 13-lined
ground squirrel and other organisms in the Large-Scale
Sequencing Program are available at: www.genome.gov/10005141.
NHGRI is one of the 27 institutes and centers at
NIH, an agency of the Department of Health and Human
Services. The NHGRI Division of Extramural Research
supports grants for research and for training and
career development at sites nationwide. Additional
information about NHGRI can be found at its Web site, www.genome.gov.