May 1, 2006, 11:58 PM CT

The Greenbeards Have Blue Throats

A new study of side-blotched lizards in California has revealed the genetic underpinnings of altruistic behavior in this common lizard species, providing new insights into the long-standing puzzle of how cooperation and altruism can evolve. The study, led by scientists at the University of California, Santa Cruz, offers the first evidence in vertebrates of an important theoretical concept in evolutionary biology known as "greenbeard" altruism.

"This reflects a major breakthrough in our understanding of how cooperative behavior arises from genes," said Barry Sinervo, professor of ecology and evolutionary biology at UCSC and first author of a paper describing the new findings. The paper would be reported in the May 9 issue of Proceedings of the National Academy of Sciences (PNAS) and is currently available in the online early edition of PNAS.

The paper describes unrelated male lizards that form cooperative partnerships to protect their territories. These partnerships are often mutually beneficial, enabling both partners to father more offspring than they would on their own. Under some circumstances, however, one male in the pair may have few or no offspring as a result of protecting its partner from the aggressive intrusions of other lizards.

This type of cooperation, in which one individual bears all the costs and another unrelated individual receives the benefits, is called "true altruism." These lizards have an annual life cycle, so this behavior may spell the end of the altruistic male's lineage.........

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April 29, 2006, 9:02 AM CT

Diagnostic Tests for monkeypox

Scientists at the Oregon NPRC developed a novel series of tests that show evidence of being more sensitive and accurate in diagnosing human monkeypox infections than current tests approved by the U.S. Centers for Disease Control and Prevention (CDC). The studies may lead to improved diagnoses, therapies, and preventive measures for monkeypox and other sometimes-deadly agents that might proliferate in a natural outbreak or a bioterror attack.

NPRC researchers Mark Slifka and Matt Lewis traveled to Wisconsin to examine more than 40 individuals who had been exposed to the monkeypox virus, a close relative of the smallpox virus. In 2003, dozens of people in the Midwest had been exposed to pet prairie dogs infected with monkeypox, and 72 cases of human infections were later reported to the CDC.

The Oregon researchers used a unique series of diagnostic tests to confirm previously unverified human infections. The diagnostic series also identified an additional three individuals whose infections had been undiagnosed because they lacked obvious symptoms. These three people, having been vaccinated against smallpox more than a decade before, were fully protected against monkeypox disease.

Slifka notes that the biocontainment level-3 laboratory associated with the Oregon NPRC is one of the few in the country with the appropriate safeguards, expertise, and authorization to conduct experiments with monkeypox. "Our studies would not have been possible without access to the NPRC or the resources of the General Clinical Research Center, where some blood analyses were performed," Slifka says. "While this research primarily focused on monkeypox, this same technology could also be used to better detect a smallpox outbreak." Although smallpox no longer exists in nature, having been eradicated through effective worldwide vaccine programs, the virus is still considered a significant bioterror threat.........

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April 29, 2006, 8:38 AM CT

Fluorescent Green Tadpoles

Robert Grainger, W. L. Lyons Brown Professor of Biology at the University of Virginia, uses NCRR support to develop genomic and genetic resources for Xenopus tropicalis, the western clawed frog of Africa. "Combining the new genomic and genetic tools with the power that frogs provide for studying early embryonic development should create a golden future for the X. tropicalis model," Grainger says. He views X. tropicalis as a much-needed complement to a related research frog, X. laevis, whose value is limited by its complex genome and long generation times.

Grainger and colleagues have so far created about 100 different genetically altered lines of X. tropicalis for use in studies of development. They manipulate the genomes of these frogs with a technique called transgenesis, or gene transfer, using parts of genes known as control or regulatory elements. These elements control gene expression-the degree to which a gene's protein product gets produced within the cell-by either promoting or repressing the transcription of the gene's DNA sequence into messenger RNA (mRNA).

The scientists first take a regulatory element that promotes the expression of some particular gene of interest. They then hook up this promoter sequence with a reporter gene-a gene that produces an easily detectable protein product such as green fluorescent protein. When this transgenic construct is introduced into frog embryos, the result is embryos whose tissues light up with the reporter-gene product whenever and wherever the original gene of interest is expressed in the developing frog. Simultaneous development of different tissues can be visualized by combining specific promoters with reporter genes that produce differently colored proteins.........

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April 29, 2006, 8:13 AM CT

Does Red Noise Increase or Decrease Extinction Risk?

Recent theoretical studies have shown contrasting effects of temporal correlation of environmental fluctuations (red noise) on the risk of population extinction. It is still debated whether and under which conditions red noise increases or decreases extinction risk compared with uncorrelated (white) noise. Here, we explain the opposing effects by introducing two features of red noise time series. On the one hand, positive autocorrelation increases the probability of series of poor environmental conditions, implying increasing extinction risk.

Conversely, for a given time period, the probability of at least one extremely bad year ("catastrophe") is reduced compared with white noise, implying decreasing extinction risk. Which of these two features determines extinction risk depends on the strength of environmental fluctuations and the sensitivity of population dynamics to these fluctuations. If extreme (catastrophic) events can occur (strong noise) or sensitivity is high (overcompensatory density dependence), then temporal correlation decreases extinction risk; otherwise, it increases it. Thus, our results provide a simple explanation for the contrasting prior findings and are a crucial step toward a general understanding of the effect of noise color on extinction risk.........

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April 29, 2006, 8:08 AM CT

No Evidence of Current Sexual Selection on Sexually Dimorphic Traits

Sexual dimorphism, especially in ornamental traits, is likely to have arisen by sexual selection. Most empirical and theoretical studies of sexual dimorphism assume that ongoing sexual selection also maintains the dimorphism. Over four seasons, I measured the sexual selection acting on three sexually dimorphic attributes (epaulet size, body size, and the blackness of the body plumage) of male red-winged blackbirds and found no consistent directional or stabilizing selection on any of them. Correlational selection was also negligible. I used path analysis to explore potential relationships in more detail but found no direct or indirect effects of male traits on either within- or extrapair success.

Males who were resident on the marsh for more years had higher within-pair success, primarily because they spent more of the season on their territory. Experimental manipulations of epaulet size and color and the extent of nonblack feathers in the black body plumage had no detectable effect on the number of within-pair mates, paternity, or the number of extrapair offspring sired in nearby territories. These results combine with data from other studies of red-winged blackbirds to suggest that, despite high variation in male mating success and hence a strong opportunity for sexual selection, several morphological attributes that differ between the sexes and vary among males are not under current sexual selection. The possible explanations for why add complexity to our understanding of how sexual selection operates.........

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April 28, 2006, 0:10 AM CT

Studying Gene Regulation In Insects

Susan Brown, an associate professor of biology at Kansas State University, is interested in how evolution generates so much diversity in insects shapes and forms.

Take the fruit fly and the beetle, for example. Even though they look very different, they have the same segmented body plan consisting of head, thorax and abdomen, Brown said. They differ, though, in how they make segments in the embryo. Fruit flies make segments all at once; beetles make segments one at a time.

"Imagine slicing a loaf of bread," Brown said. "Segmentation in fruit flies is similar to a pre-sliced loaf of bread. In other insects and even humans, segments are added one at a time, like slicing a loaf of freshly baked bread."

It is this segmentation that is the basis of a paper by Brown and two K-State doctoral students. The appears in a recent edition of Proceedings of the National Academy of Science.

"We wanted to know how the same genes that slice a space like a loaf of bread can also add slices one at a time," Brown said.

As per Brown, the groundwork for this research was laid about 20 years ago when researchers first learned about the genes that regulate embryonic development in the fruit fly. She said one question that a number of researchers have been asking since is do other insects have those same genes? If they do, what role do these genes play to give insects such different ways of making segments?.........

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April 26, 2006, 7:34 PM CT

Metamorphosis Gene Is Key For Insects Like Grasshoppers

It is a marvel of nature that a creature such as a caterpillar changes into something quite different, a butterfly. Contrast that with a grasshopper, which looks largely the same from the time it hatches through its adult stage.

New University of Washington research shows that a regulatory gene named broad, known to be necessary for development of insects that undergo complete metamorphosis, also is key for the maturation of insects that have incomplete metamorphosis. The work appears to present the first molecular evidence that the nymphal stage in lower insects is equivalent to the pupal, or chrysalis, stage of advanced insects such as butterflies.

Metamorphosis evolved in insects about 300 million years ago from ancestors of direct-developing insects such as grasshoppers. Biologists know the broad gene regulates metamorphosis in flies and moths and is found only at the transition between their larval and pupal stages. To understand how metamorphosis evolved in insects, the UW scientists examined how the broad gene functions in direct-developing insects, which don't have a pupal stage.

"We found that it is expressed throughout the nymphal stages, and that it is also mandatory for change," said Deniz Erezyilmaz, a UW biology research associate. "So it looks like metamorphosis evolved in insects by restricting the expression of the broad gene to a short but intense period of change at the transition from larva to pupa."........

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April 26, 2006, 6:48 PM CT

Helpful Dose Of Hormones From The Mother

Researchers have discovered that a dominant hyena puts her cubs on the road to success before they are born by passing on high levels of certain hormones that make her budding young leaders more aggressive and sexually advanced.

The report, reported in the April 27 issue of Nature, is the first study in mammals to demonstrate a relationship between a female's social rank and her ability to influence her offspring's behavior through prenatal hormone transfer. Previously, this phenomenon had only been documented in birds.

Michigan State University's Kay Holekamp, together with her colleagues, spent almost 10 years sampling androgen levels from free-ranging hyenas in Kenya. Androgens are hormones, such as testosterone, that control development of typically masculine characteristics like aggression, muscle development and sexual behavior.

The team found that alpha females had higher androgen levels late in pregnancy when compared to the subordinate, pregnant females in the pack. Consequently, the cubs of the alpha females were more aggressive and exhibited more sexual play, characteristics that elevate the chances for life-success in both sexes.

In hyena packs, male-female social roles are reversed from what is normally found in nature--that is, female hyenas are larger, more aggressive and dominate the group. They even have deceptively male-like genitalia, leading to the misconception that they are hermaphrodites.........

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April 24, 2006, 6:36 PM CT

Reproductive Success In Early Life Leads To Faster Ageing

Why do we stop reproducing after a certain age, and how is this age determined? A study by Oxford University researchers has shed light on this question by studying data from Dorset swans.

A theory which says that reproductive success in early life will lead to faster ageing later has been supported by the study of mute swans (Cygnus olor) which shows that those swans which reproduce early in life also stopped breeding early, and vice versa. Which pattern a swan adopts appears to be genetically inherited.

The team, from the Edward Grey Institute in Oxford's Department of Zoology, investigated data on swans that bred as youngsters and those that started to reproduce at a much later age. They discovered the age at which swans started to reproduce varied considerably - from two to twelve years old - and the age at which swans stopped breeding also showed huge variation - from two to twenty years old. The main finding, however, was that the birds that started breeding at an early age stopped reproducing earlier than the late-starters.

The study, would be published in the science journal PNAS this week, supports the 'antagonistic pleiotropy' theory for the evolution of ageing, that says that you 'pay' in later life for your success in reproducing when young. It is thought the study is the first to show this pattern in a wild animal population.........

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April 22, 2006, 6:21 PM CT

Healthy Backyard

Look up! Breathe deep! Earth Day comes during one of the sweetest-smelling, most radiant times of the year. You don't have to go far to celebrate nature, as migrating birds return to your backyard, neighborhood parks brim with petals, and the warm weather melts our cabin fever away.

Around the globe, more than half a billion people are celebrating the 36th annual Earth Day, and finding ways to make the world a greener place. So get involved! As the premier organization dedicated to conserving wildlife of every hue and stripe and speckle and spot, we invite you to join us in our commitment by practicing these Earth-friendly suggestions.

Cheep cheep! Like the sounds of a backyard chorus? Visit http://www.wcs.org/birdgardening to find out how you can provide a friendly environment for the wild birds that share our city and suburbs.

Garden for the bugs! Learn how planting flowers that will attract insects like earthworms, butterflies, and midge flies to your yard keeps it green and healthy. Visit for a list of bug bytes.

Like a shore dinner? Learn how to choose seafood that comes from healthy, thriving fisheries by visiting http://www.wcs.org/gofish, where you can print out a seafood wallet card to carry with you.

Reduce, reuse, recycle. With the continual growth of the "human footprint," or human influence, on the Earth's land surface, the world's resources are at stake. But nature is often resilient if given half a chance. By finding ways to tread more gently on the planet, and to co-exist with wildlife, we can help offer that chance.........

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