of the Year: Watching Evolution In Action
One of the most dramatic evolution
results came in September, when an international
team published the genome of our closest relatives,
the chimpanzee, including Tammy, who lives at
the Saint Louis Zoo.
[Photo by Carol Weerts, Saint Louis Zoo]
Evolution has been the foundation and guiding theory of biology since
Darwin gave the theory its proper scientific debut in 1859. But Darwin
probably never dreamed that researchers in 2005 would still be uncovering
new details about the nuts and bolts of his theory — how does
evolution actually work in the world of influenza genes and chimpanzee
genes and stickleback fish armor? Studies that follow evolution in
action claim top honors as the Breakthrough of the Year, named by
its publisher AAAS, the nonprofit science society.
In 2005, scientists piled up new insights about evolution at the
genetic level and the birth of species, including information that
could help us lead healthier lives in the future. Ironically, these
often-startling discoveries occurred in a year when backers of “intelligent
design” and other opponents of evolution sought to escalate
challenges to this fundamental concept.
This milestone, plus nine other research advances, make up Science’s
list of the top 10 scientific developments in 2005, chosen for their
profound implications for society and the advancement of science.
Science’s Top Ten list appears in the 23 December
2005 issue of the journal Science.
Many of this year’s breakthrough studies followed evolution
at the genetic level. In October this year, an international team
of researchers unveiled a map of the chimpanzee genome. Scientists
are already poring over the chimpanzee genome and another international
effort, the biggest map to date of single-letter variations in the
human genetic sequence, hoping to get a better glimpse of the human
species' evolutionary history. The two studies give scientists new
material for studying conditions from AIDS to heart disease, and may
lay the groundwork for a future of personalized genetic medicine.
This year's sequencing of the 1918 pandemic flu virus could have
a more immediate impact on medicine. The amazing story of flu genes
preserved in permafrost and painstakingly reconstructed has a chilling
coda: the deadly flu seems to have started out as purely a bird virus.
Understanding the evolution of last century's deadly bird flu may
help us predict and cope with the current bird flu threat.
With the human genome already in
hand, researchers lined up chimp and human DNA
and examined, one by one, the 40 million evolutionary
events that separate them from us. In this photo,
a young chimpanzee in Uganda's Kibale National
Park, feeds on Ficus natalensis.
[Photo by Jean-Michel Krief]
Other studies showed how small changes in DNA can trigger
dramatic evolutionary events. Researchers found that
a single genetic change can be all it takes to turn
one species into many, as in the case of the Alaskan
stickleback fish that lost its armor and evolved from
an ocean-loving species to a variety of landlocked lake
Beyond the genome, researchers watched evolution in action among
a number of animals, from caterpillars to crickets, and found that
behavioral differences such as what to eat and when to mate may be
enough to turn a single population into two species. These painstaking
observations and other experiments showed that evolutionary studies
are as relevant to 2005 as they were to 1859.
Science also salutes nine other scientific achievements
Planetary Safaris: With spacecraft at or on the
way to the moon, Mercury, Venus, Mars, a comet, an asteroid, Saturn
and the very edge of the solar system, planetary discovery soared
in 2005. The high point in a year of highlights may be the landing
of the European spacecraft Huygens on Titan, Saturn's largest moon.
Huygens’ trip to Titan revealed a world where infrequent but
drenching rains of liquid methane shape the land and participate in
a fascinating hydrologic cycle.
A Rich Year for Plants: Several key molecular cues
behind flowering and other plant mysteries and surprises came to light
in 2005. For example, plant molecular biologists pinned down the identity
of a signal that initiates the seasonal development of flowers. Other
research focused on a gene involved in stimulating flowering, and
another study highlighted a surprising cache of RNA.
The Nature of Neutron Stars: In 2005, new instruments
yielded vivid insights into the most violent behaviors of neutron
stars. A short, intense pulse of radiation from near the center of
the Milky Way, recorded on 27 December 2004, may be the result of
a short gamma ray burst — a rapid merger of two ancient neutron
stars or a neutron star and a black hole.
Brain Wiring and Disease: Several studies in 2005
suggest that diseases such schizophrenia, Tourette syndrome, and dyslexia
are rooted in "faulty wiring" of the brain's neural circuitry
during development in the womb.
Where Did Earth Come From?: This year, researchers
took another look at Earth rocks and meteorites that resemble the
starting material of the solar system and found that their atoms were
significantly different. So where did Earth get its building blocks?
Some scientists now say early Earth materials come from a different
part of the solar system, while others say parts of early Earth are
just sunk deep in the planet, hidden from view.
Key Protein's Close-up: The most detailed molecular
portrait to date of a voltage-gated potassium channel was unveiled
in 2005. These channels, gatekeeper proteins that usher potassium
ions in and out of cells, are as key to nerve and muscle functioning
as transistors are to computers.
Changing Climate of Climate Change?: In 2005, evidence
linking humans to global warming continued to accumulate and U.S.
politicians began to take notice. From the warming of deep ocean waters
and increased frequencies of the most intense tropical cyclones to
continued reductions in ice cover in the Arctic Ocean and altered
bird migratory patterns, scientific evidence for climate change built
up in 2005 and non-scientists seem to have listened.
Cell Signaling Steps Up: Dynamic views of how cells
respond to the chemical and environmental signals all around them
took hold in 2005 thanks to efforts to track multiple inputs and outputs
of cell signaling networks simultaneously. For example, researchers
created a model of nearly 8,000 chemical signals involved in a network
leading to programmed cell death.
ITER Lands in France: The struggle over the location
of the world's first fusion reactor has ended — the International
Thermonuclear Experimental Reactor (ITER) will be built at Cadarache
in southern France and not in Rokkasho, Japan. One aim of ITER is
to generate fusion-powered electricity by recreating the power of
the sun on Earth.
Science’s Breakdown of
the Year — U.S. Particle Physics: With the cancellation
of two major experiments and talk of an early closing for one of the
three existing particle colliders, U.S. particle physics is Science’s
breakdown of 2005. As the U.S. program founders, particle physics
research around the world could suffer. A bit of good particle physics
news did emerge in 2005, however — researchers around the world
remain committed to building the International Linear Collider, a
multibillion-dollar global facility that may be the key to the future
of particle physics.
Areas to watch in 2006: This year, Science’s
predictions for hot fields and topics in the upcoming year include
drug and vaccine development for avian flu, RNA-interference in humans,
high-temperature superconductors, the microbial family tree, detection
of the merging of two neutron stars and ultrahigh-energy cosmic rays
— the speediest atomic nuclei in the universe. Researchers will
also be on the lookout for more evidence for the ivory-billed woodpecker
and solid helium flowing like a liquid.
This press release is also available in Chinese,
An audio file with Science news staff discussing Science's
Breakthrough of the Year runners up will be available to the public
on Thursday 22 December. To listen, click
To access a podcast feed, click
Daniel B. Kane
22 December 2005