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Domain: biologists.org
Stories and comments across the archive that link to biologists.org.
Stories · 5
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Genetically-Modified 'Surrogate Hens' Could Lay Eggs of Rare Chicken Breeds, Scientists Say (theguardian.com)
In an effort to preserve rare varieties of chicken breeds and diversify the chicken gene pool, scientists at the University of Edinburgh's Roslin Institute have come up with a plan to breed genetically-modified chickens designed to act as surrogates that would be capable of laying eggs from any rare breed. Such rare breeds include the Nankin, Scots Dumpy and Sicilian Buttercup. The Guardian reports: The surrogacy technique, which places a new, mind-bending twist on the classic chicken or egg question, involves first genetically engineering hens to be sterile. This is done by deleting a gene, called DDX4, that is required for the development of primordial follicles (the precursors to eggs) meaning that the surrogate hens will never lay eggs that are biologically their own. The next step will be to transplant follicles from rare birds into the surrogate (this is done before the surrogate chick is hatched from its own egg), meaning it would go on to lay eggs belonging to entirely different breeds of chicken. Given that the hens would also need to be artificially inseminated with sperm from the same rare variety, the approach may appear unnecessarily convoluted. Why not just breed the rare birds the normal way? The scientists' ultimate goal is to create a gene bank of chicken breeds preserved for posterity, and since primordial follicles can be frozen efficiently, while eggs cannot, the surrogacy technique serves an essential work-around. Mike McGrew, who is leading the project and is the first author on a paper on the work published this week in the journal Development, predicts that the surrogates will be able to lay eggs from any breed, including chicken's wild predecessor, the red junglefowl, but he is doubtful about whether it will work efficiently across species -- it is not likely that the surrogate hens will be giving birth to eagle chicks, for instance. Richard Broad, a field officer for the Rare Breeds Survival Trust, agreed that rare chickens could be a source of valuable genetic variation, potentially carrying variants that would provide resistance against new forms of avian flu. At present, the team is focused on chicken breeds, but expects the technique to work to preserve rare varieties of ducks, geese and quail. -
For the First Time, Organ Regenerated Inside a Living Animal
ananyo (2519492) writes "Scientists at Edinburgh University have successfully persuaded an organ to regenerate inside an animal. As they report in the journal Development, they have treated, in mice, an organ called the thymus, which is a part of the immune system that runs down in old age. Instead of adding stem cells they have stimulated their animals' thymuses to make more of a protein called FOXN1. This is a transcription factor (a molecular switch that activates genes). The scientists knew from earlier experiments that FOXN1 is important for the embryonic development of the thymus, and speculated that it might also rejuvenate the organ in older animals. They bred a special strain of mice whose FOXN1 production could be stimulated specifically in the thymus by tamoxifen, a drug more familiar as a treatment for breast cancer. In one-year-olds, stimulating FOXN1 production in the thymus caused it to become 2.7 times bigger within a month. In two-year-olds the increase was 2.6 times. Moreover, when the researchers studied the enlarged thymuses microscopically, and compared them with those from untreated control animals of the same ages, they found that the organs' internal structures had reverted to their youthful nature." -
Flying Snake Mysteries Revealed
Rambo Tribble writes "Researchers from Virginia Tech are reporting they have uncovered the secrets behind the genus Chrysopelea's aerodynamic feats . These ophidians are capable of gliding some distance while appearing to slither through the air. The BBC's article on the revelations hosts a short video of the phenomenon. At the heart of Chrysopelea's feat is a remarkable ability of the snakes to alter their body's cross-section. Finally, snakes that don't need to be on no stinking plane." The paper [PDF] has some more cool pictures, too. -
Flying Snake Mysteries Revealed
Rambo Tribble writes "Researchers from Virginia Tech are reporting they have uncovered the secrets behind the genus Chrysopelea's aerodynamic feats . These ophidians are capable of gliding some distance while appearing to slither through the air. The BBC's article on the revelations hosts a short video of the phenomenon. At the heart of Chrysopelea's feat is a remarkable ability of the snakes to alter their body's cross-section. Finally, snakes that don't need to be on no stinking plane." The paper [PDF] has some more cool pictures, too. -
"Cyber-Roach" Forces Rethink On Animal Movement
Lanxon writes "A team of researchers at the Royal Veterinary College in London has built a 'cyber-cockroach' (a cockroach wearing an accelerometer in a tiny backpack) to try and better understand the movements of many-legged animals. They found that unlike bipedal creatures, animals with more than two legs don't adjust their movements when walking over a softer surface." The academic paper is available from the Journal of Experimental Biology. This research will be helpful in finding better ways for multi-legged robots to navigate difficult terrain.