fitness

Researchers reveal the infectious impact of salmon farms on wild salmon

...ger than the farm itself." Sea lice can lower the fitness of salmon - and in some cases be lethal - as they create open lesions on the surface of the fish that compromises a fish's ability to maintain its salt-water balance. When infection rates are high enough, the parasites feed on the fish at rates great...

Amino acids in nectar enhance butterfly fecundity: A long awaited link

...e significance of nectar amino acids for butterfly fitness and insinuated that butterflies have acted as agen...id production by plants, nectar preferences of and fitness benefits to butterflies. This article by Jovanne Mevi-Schütz and Andreas Erhardt will appear in the...

Vascular structure and function improve with diet and exercise

...t and physical activity prescribed were matched to fitness level in an individually tailored fashion and delivered in a family practice setting as opposed to a hospital or laboratory." The randomized, single-blind trial of SNAC intervention versus usual care lifestyle counseling included 38 patients with hi...

Report that delayed motherhood decreases life expectancy of mouse offspring

... offspring. Several other aspects of reproductive fitness of offspring were assessed, but none showed significant deleterious effects. This report identifying effects of delayed motherhood on life expectancy and body weight of offspring will surely stimulate inquiries into mechanisms resulting in these dis...

Science study holds implications for gene therapy and stem cell biology

...ruses as a tool to discover genes that enhance the fitness of stem cells. Such genes are of great interest fo...e the availability of genes that enhance stem cell fitness using this novel approach. Simultaneously, we need to study whether similar genes regulate the behav...

Men Estimate Men's Risks Of Common Disorders Higher Than Women Do, And Vice Versa

... tendency was also evident in the one condition -- fitness -- posed in positive terms. "Previous studies on personal risk assessments suggest a tendency to underestimate one's own risk of illness compared to one's peers -- this is often referred to as optimism bias. Our findings suggest in contrast that wha...

Gene loss accelerates aging

...mage available on request) were hair loss, reduced fitness and body weight, progressive curvature of the spine, and a shortened lifespan. "Aging and cancer are two sides of the same coin. In one case, cells stop dividing and in the other, they can't stop dividing. We suspect that having the right amount of ...

DDT-resistant insects have additional genetic advantage that helps resistance spread

...nes themselves. "Experimenters looking at genetic fitness in resistant insects often only look at single cha...s that are genetically unrelated. "Differences in fitness therefore often correspond to differences in genetic background rather and are not due to the resist...

Costly breeding programs for endangered species pay off

...n both breeding groups exhibited similar levels of fitness and fertility as long as they remained in a contro...me a pair of flies mated, researchers measured the fitness of the pair by counting the number of eggs the female laid, and by measuring the number of eggs that...

Weapon performance determines mating success in the collared lizard

...rmance (i.e., bite force) is a better predictor of fitness than body size and weapon size. The study finds t...luence fight outcomes, has far stronger effects on fitness than size. The strong influence of weapon performance on reproductive success suggests that selectio...

MicroRNAs have shaped the evolution of the majority of mammalian genes

...s, in order to maintain their functions and ensure fitness of the organism, have quickly lost sites that pair up with microRNAs. In addition to the thousands of cases where genes have avoided microRNA targeting, Farh also investigated the opposite extreme, cases where genes have maintained microRNA target s...

A bug's life: Exceptional genomic stability yet rapid protein evolution in a carpenter ant mutualist

...nome evolution, as well as the consequences on the fitness of the bacterium and its host. "Developments in endosymbiosis are important not only to questions in basic research, but may have important practical implications," notes Wernegreen. "A very promising area of endosymbiont research is the manipulation...

Computer models aid understanding of antibody-dependent enhancement in spread of dengue fever

...c effects of antibody-dependent enhancement on the fitness of viruses" was written by Derek A. T. Cummings, Ira B. Schwartz, Lora Billings, Leah B. Shaw and Donald S. Burke. Cummings and Burke are with the Johns Hopkins Bloomberg School of Public Health. Schwartz and Shaw are with the Naval Research Laborato...

Getting an evolutionary handle on life after reproduction

... postreproductive females should contribute to the fitness of their offspring or relatives, a hypothesis call...on whether postreproductive lifespan can influence fitness enough to be under selection. But in a field dominated by investigations into the origins of human m...

Fish evolve a longer lifespan by evolving a longer reproductive period, researchers find

...er they stop reproducing, do not contribute to the fitness of young fish. As a result, the post-reproductive ...at post-reproductive humans can increase their own fitness by contributing to the fitness of their grandchildren and that the prolonged post-reproductive lifes...

Removing egg from nest may help save endangered whooping crane

...a single chick to protect. Even though long-term fitness is almost the same whether one egg or two is laid, the risk of extinction for the Wood Buffalo-Aransas whooping crane population is lowest when eggs are removed, says Boyce. He recognizes the need to minimize human influence in national parks, but s...

Genetic analysis of cavefish reveals more about evolution

.... Therefore, it doesn't diminish other aspects of fitness when it is mutated. ...

Evolutionary conservation of a mechanism of longevity from worms to mammals

... elegans gene clk-1, results in increased cellular fitness and prolonged lifespan in mice. The gene clk-1 in the worm, as well as mclk1 in mice, encodes an enzyme necessary for the biosynhesis of ubiquinone, an essential cofactor in numerous redox reactions such as mitochondrial respiration. Though lack ...

Plants, too, have ways to manage freeloaders

...ore cooperative rhizobia by manipulating bacterial fitness in the nodule," the authors wrote. "We think that when roots explore the soil and encounter bacteria, they will nodulate them, but then the plant will evaluate how much nitrogen it's getting from the bacteria and the efficiency with which it's getti...

Spring migration of pink-footed geese under threat

.... Our model shows that naïve geese have much lower fitness than experienced geese, which are able to anticipate and adapt to changes in their environment." There are two discrete populations of pink-footed goose: the Greenland/Iceland population, which breeds in Iceland and Greenland and overwinters in Brit...

Escapee farmed salmon infiltrate fitter wild populations

...may alter the gene pool of wild salmon, reduce its fitness and accelerate its decline." ...

'Genetic network' guards against lethal DNA damage

...e genetic interactions, which are called synthetic fitness or lethality interactions. Synthetic lethality is ...ffects of 5,000 different double mutations on cell fitness in a single experiment. With this technology, only 5,000 tests would be required to map the 25 milli...

Viral 'fitness' explains different resistance patterns to aids drugs

...f medication also factors in. Differences in viral fitness of mutated resistant virus occur between different...ttention should be given in defining how virologic fitness determines how different patterns of taking medications may lead to resistance" said Steven Deeks, M...

Males with elevated levels of testosterone lead shorter lives but have more success siring offspring

...at testosterone-treated males had a higher overall fitness than control males," write the authors in a study in the May issue of American Naturalist. This led to the question of why don't juncos naturally have higher levels of testosterone? Testosterone-treated males produced more offspring, but they were ...

Evolution follows few of the possible paths to antibiotic resistance

...tion are likely to result in continuously improved fitness and therefore be relevant to the process of natural selection. ...

Contaminants linked to sturgeon decline in Columbia river

...ed, "and exhibited reduced growth and reproductive fitness when compared to fish sampled in other locations. These data suggest that some contaminants may be accumulating behind dams over time." North America's largest freshwater fish, white sturgeon can grow to 20 feet in length, weigh more than 1,500 poun...

U of M study examines kidney stone prevention in astronauts

...eve enough resistance to maintain their pre-flight fitness levels. "This becomes a real health concern, as the time astronauts spend in space and living in the space station is extended," said Manoj Monga, M.D., professor of urologic surgery and lead investigator. The study will be published in the July 200...

Study reveals how cells destroy faulty proteins in cystic fibrosis

...unds known as chemical chaperones can increase the fitness of misshaped CFTR and get it into proper shape. Thus, "If we can figure out how to get CFTR into the right shape, we can cure the disease," Cyr said. To better understand how to fix CFTR, Cyr's research team at the UNC Cystic Fibrosis Pulmonary R...

The higher the hierarchy, the greater the aggression

...ors. Cant et al. conclude that variation in future fitness due to inheritance rank is the hidden factor accounting for much of the variation in aggression among apparently equivalent individuals. ...

Report warns about carbon dioxide threats to marine life

...tion is: "What does this mean in terms of organism fitness and the future of marine ecosystems?" ...

Mobile DNA part of evolution's toolbox

..."And to the extent that [such changes] improve the fitness of an organism," says Haussler, "they eventually will become fixed in a population." "This suggests a lot of exciting evolutionary avenues," says Haussler, "but we don't yet know how prevalent this kind of evolution is." Other labs have found simil...

Beauty and the brain

...ttractiveness), prototypicality signals health and fitness ?unusually protuberant eyes might be a clue to disease, for example ?and so is a kind of shorthand for the value of a potential mate. But whereas that explanation makes intuitive sense when it comes to human faces, Winkielman said, it strains cred...

Protowings may have helped bird ancestors cover rough terrain

... it is not immediately evident what improvement in fitness would result from ancestral, partly evolved wings. Two theories have recently dominated the debate: one postulates that flight evolved in tree-dwelling ancestors that used their forelimbs to help them glide, while the other considers ancestral birds ...

A human taste for rarity spells disaster for endangered species

...ls of many plant and animal species suffer reduced fitness at low population densities, which increases their extinction risk. The authors' model now shows that humans can trigger an "anthropogenic Allee effect" in rare species through a paradox of value. When rarity acquires value, prices for scarce species...

Buildup of damaged DNA in cells drives aging

... from our parents. The second is that lifespan and fitness in old age is determined by how much damage we incur over our lifetime. "Our study suggests that both of these hypotheses are correct. Damage, including DNA damage, drives the functional decline we all experience as we age. But how we respond to ...

Walking not enough for significant exercise benefits

...exercise program to the test against a traditional fitness program which incorporated cardio-based activities... energy expenditure, we found that the traditional fitness program improved aerobic fitness and reduced systolic blood pressure, more than the 10,000-step life...

Does natural selection drive the evolution of cancer?

...benign cells in a tumor to increase their relative fitness over their malignant neighbors. This would allow t...Maley says. "In this case, you try to increase the fitness of chemosensitive cells so that they outcompete any resistant cells that are in the tumor. And then ...

How did bilaterally symmetric flowers evolve from radially symmetric ones?

...xplored how different flower shapes affected plant fitness in natural populations of Erysimum mediohispanicum, a Mediterranean herb. Their findings will be published in the October issue of The American Naturalist. The researchers found that plants bearing bilaterally symmetrical flowers were more visited ...

Fruit flies and global warming -- Some like it hot

...nt heat hardening treatments to get estimates of a fitness component in the wild. They used the likelihood to... sites without natural resources as an estimate of fitness in Drosophila. The results showed that heat treated flies were much more often caught at the baits a...

Childhood obesity among Quebec Cree raises concerns

...ool students exhibited very low levels of physical fitness and physical activity. Diet is another obvious possibility to consider. This University of Alberta research is ongoing—and there’s no question that it is timely. The federal government has just announced the release of a new version of the Canada ...

Fitness has fallen since the days of Ancient Greece

...ld struggle to find enough people at that level of fitness today to power the ships at those speeds." Triremes were a huge technological advance, allowing Athens to dominate the seas. They had a strong keel, taken forward into a huge spike covered in bronze plates, which meant they could ram and hole enem...

The penalty of having a sister -- why sibling sex matters for male saiga antelopes

... an amplified negative effect on male reproductive fitness in species where competition amongst males for mates is very high." The saiga antelope provides scientists with an ideal opportunity to investigate the effects of mixed-sex twin litters on size and development, because there are a high proportion ...

Helium helps patients breathe easier

...ercise, which may improve their exercise capacity, fitness level and as a result, quality of life," Eves said. ...