Genetic chip will help salmon farmers breed better fish

Atlantic salmon production could be boosted by a new technology that will help select the best fish for breeding.The development will enable salmon breeders to improve the quality of their stock and its resistance to disease.A chip loaded with hundreds of thousands of pieces of DNA — each holding a fragment of the salmon’s genetic code — will allow breeders to detect fish with the best genes.It does so by detecting variations in the genetic code of each individual fish — known as single nucleotide polymorphisms (SNPs). These variations make it possible to identify genes that are linked to desirable physical traits, such as growth or resistance to problematic diseases, for example sea lice infestations.Salmon breeders will be able to carry out the test by taking a small sample of fin tissue.The chip carries over twenty times more genetic information than existing tools. Similar chips have already transformed breeding programmes for land-farmed livestock including cattle and pigs.Salmon farming contributes around half a billion pounds to the UK economy each year and provides healthy, high quality food. Worldwide, approximately 1.5 million tonnes of Atlantic salmon are produced every year.Scientists from the University of Edinburgh’s Roslin Institute and Edinburgh Genomics initiative developed the chip with researchers from the Universities of Stirling and Glasgow. They worked with industrial partners Affymetrix UK and Landcatch Natural Selection. The work was funded by the UK’s innovation agency — the Technology Strategy Board — and the Biotechnology and Biological Sciences Research Council.The chip is highlighted in a study published today in the journal BMC Genomics and it will be available to breeders and farmers from March 2014.Dr Ross Houston, of The Roslin Institute, said: “Selective breeding programmes have been used to improve salmon stocks since the 1970s. This new technology will allow the best breeding fish to be selected more efficiently and accurately, particularly those with characteristics that are difficult to measure such as resistance to disease”Dr Alan Tinch, director of genetics at Landcatch Natural Selection, said: “This development takes selective breeding programmes to a whole new level. It is an extension to the selective breeding of salmon allowing more accurate identification of the best fish to create healthier and more robust offspring.”Story Source:The above story is based on materials provided by University of Edinburgh. Note: Materials may be edited for content and length.

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Why are consumers less likely to buy a product when it’s the only option?

July 26, 2013 — Consumers are more likely to search for alternatives when they are given only one option, according to a new study in the Journal of Consumer Research.”There has been a lot of recent attention devoted to the pitfalls of presenting consumers with too many options. However, consumers may also react negatively when choices are too restrictive. Isolating an option, even temporarily, may increase how much consumers search and potentially the likelihood that they make no purchase,” writes author Daniel Mochon (Tulane University).Suppose a consumer really wants to buy a camera. Narrowing the selection should make it easier to choose from one of the available options. Reducing the selection to just a single camera should make it even easier, but it doesn’t. In fact, consumers may be less likely to choose a specific camera when it’s the only option.In one study, consumers were asked to purchase a DVD player. One group was presented with a Sony DVD player, a second group was presented with a Philips DVD player, and a third group was presented with both options. Consumers were more likely to make a selection when they were presented together than when each was presented alone.Giving consumers only one option increases their desire to search for more options. As a result, they might reject a product they would otherwise purchase. For example, a consumer shopping for a DVD player may be willing to purchase a Sony model when another option is also available, but unwilling to purchase the same Sony when it’s the only option.”Companies should consider how options are presented to consumers. …

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Evolution shapes new rules for ant behavior, research finds

May 15, 2013 — In ancient Greece, the city-states that waited until their own harvest was in before attacking and destroying a rival community’s crops often experienced better long-term success.

It turns out that ant colonies that show similar selectivity when gathering food yield a similar result. The latest findings from Stanford biology Professor Deborah M. Gordon’s long-term study of harvester ants reveal that the colonies that restrain their foraging except in prime conditions also experience improved rates of reproductive success.

Importantly, the study provides the first evidence of natural selection shaping collective behavior, said Gordon, who is also a senior fellow at the Stanford Woods Institute for the Environment.

A long-held belief in biology has posited that the amount of food an animal acquires can serve as a proxy for its reproductive success. The hummingbirds that drink the most nectar, for example, stand the best chance of surviving to reproduce.

But the math isn’t always so straightforward. The harvester ants that Gordon studies in the desert in southeast Arizona, for instance, have to spend water to obtain water: an ant loses water while foraging, and obtains water from the fats in the seeds it eats.

The ants use simple positive feedback interactions to regulate foraging activity. Foragers wait near the opening of the nest, and bump antennae with ants returning with food. The faster outgoing foragers meet ants returning with seeds, the more ants go out to forage. (Last year, Gordon, Katie Dektar, an undergraduate, and Balaji Prabhakar, a professor of computer science and of electrical engineering at Stanford, showed that the ants’ “Anternet” algorithm follows the same rules as the protocols that regulate data traffic congestion in the Internet).

Colonies differ, however, in how they use these interactions to regulate foraging. Some colonies are likely to forage less when conditions are dry. These same, more successful colonies are also more likely to forage more steadily when conditions are good.

Gordon found that it’s more important for the ants to not waste water than to forage for every last piece of food. There’s no survival cost to this strategy, even though the colonies sometimes forgo foraging for an entire day. Instead, not only do the colonies that hunker down on the bad days live just as long as those that go all out, they also have more offspring colonies.

“Natural selection is not favoring the behavior that sends out the most ants to get the most food, but instead regulating foraging to hold back when conditions are bad,” Gordon said. “This is natural selection shaping a collective behavior exhibited by the entire colony.”

Gordon’s group is still investigating how the ants gauge humidity, but they have determined that the collective response of the colony to conditions is heritable from parent colony to offspring colony. Even though a daughter queen will establish her new colony so far from the parent colony that the two colonies will never interact, the offspring colonies resemble parent colonies in their sensitivity to conditions.

Although the foraging activity of the offspring colonies and the parent colony didn’t entirely match up on all days, they were similar on extreme days: parent and offspring colonies made similar judgments about when to lie low or take advantage of ideal conditions.

While the region has experienced 10 to 15 years of protracted drought, and the more restrained colonies will most likely fare better reproductively as that trend continues, Gordon can’t yet say whether the emphasis on sustainability evolved in response to climate change pressures.

“What’s evolving here are simple rules for how ants participate in a network that regulates the collective behavior of the colony,” she said.

The work is published in the May 16 issue of the journal Nature.

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