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Deadly poisons meet their match
Research news and discovery
PHILIPPE CLEMENT/NATUREPL.COM
In brief– There be giants
Monarchs of the glen end up with underachiever daughters GOOD genes for males are not necessarily good genes for females too. In red deer at least, popular males tend to father rather unsuccessful daughters. The finding could help to explain the paradox of why poor genes often persist and genetic variation isn’t lost over time. Katharina Foerster of the University of Edinburgh, UK, and colleagues studied data collected over the last 40 years from the Isle of Rhum, off Scotland’s west coast. They measured the success of individual deer based on their lifespan and the number and survival rate of their offspring.
The most successful male deer tended to father daughters that weren’t so successful (Nature, vol 447, p 1107). “The daughters had less breeding success and produced fewer calves than average,” says Foerster. Meanwhile, male deer that carried genes corresponding to greater female success didn’t father as many calves. This mismatch could help explain why some poor traits don’t die out. “We see this sexually antagonistic selection because the male and female deer need to fulfil different requirements in order to be successful,” says Foerster. The team think that this twist on the battle of the sexes is likely to occur in any species where there are physical differences between the male and female – perhaps including humans.
Moon recipe: smash planets and stir THE Earth and moon share a past etched in silicon, and it hints that the favoured theory of how the moon formed isn’t quite right. Most astronomers believe that the moon formed when a Marssized object struck Earth. If this is the case, the moon should contain mainly rock from the impacting body. However, Alex Halliday of the University of Oxford and his colleagues have evidence www.newscientist.com
suggesting that this isn’t so. The team studied the ratios of light to heavy isotopes of various elements in rock from the Earth, moon and meteorites. For most elements, the composition was the same, but samples from the Earth and moon showed a puzzling preference for the heavy forms of iron and silicon. The moon’s isotopic make-up was identical to Earth’s,
with no trace of an impacting object (Nature, vol 447, p 1102). Halliday thinks that the results support a modified giant impact theory proposed two years ago by Kaveh Pahlevan and Dave Stevenson of the California Institute of Technology, Pasadena. They suggested that the impact of a Mars-sized body first created a hot cloud of rock vapour. This mixed together as it cooled – obliterating any unique isotopic signatures of the impacting body – before forming the moon.
A PENGUIN big enough to look you in the eye is hardly what you’d expect to find in the tropics. But 36 million years ago, giant 1.5-metre penguins roamed the Peruvian coast. Large size in penguins is thought to be an adaptation to conserve body heat, so Mario Urbina of the National University of San Marcos in Lima was surprised to find that the giants, named Icadyptes salasi, lived in the tropics at a time when Earth was much warmer. The global cooling that covered Antarctica with ice sheets didn’t start until about 34 million years ago, 2 million years after Icadyptes had died out (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0611099104). “We don’t know how the large penguins would have thermoregulated on land,” says Julia Clarke of North Carolina State University in Raleigh. They probably spent most of their time in the water.
Deadly poisons meet their match RICIN, cholera toxin and shiga toxin, produced by deadly strains of E. coli, are the stuff of every poisoner’s handbook – because there is no antidote. Now Jose Saenz and colleagues at Washington University School of Medicine in St Louis, Missouri, may have found one. These toxins travel backwards through a cell’s protein-making pathway, passing through the Golgi network and endoplasmic reticulum before interrupting protein synthesis. Saenz’s team screened 14,400 small molecules for compounds that could halt this journey without disrupting normal cell function. They found two such molecules which, if safe, could lead to treatments for these poisons (Infection and Immunity, DOI: 10.1128/IAI.00442-07). 30 June 2007 | NewScientist | 19
PHILIPPE CLEMENT/NATUREPL.COM
In brief– There be giants
Monarchs of the glen end up with underachiever daughters GOOD genes for males are not necessarily good genes for females too. In red deer at least, popular males tend to father rather unsuccessful daughters. The finding could help to explain the paradox of why poor genes often persist and genetic variation isn’t lost over time. Katharina Foerster of the University of Edinburgh, UK, and colleagues studied data collected over the last 40 years from the Isle of Rhum, off Scotland’s west coast. They measured the success of individual deer based on their lifespan and the number and survival rate of their offspring.
The most successful male deer tended to father daughters that weren’t so successful (Nature, vol 447, p 1107). “The daughters had less breeding success and produced fewer calves than average,” says Foerster. Meanwhile, male deer that carried genes corresponding to greater female success didn’t father as many calves. This mismatch could help explain why some poor traits don’t die out. “We see this sexually antagonistic selection because the male and female deer need to fulfil different requirements in order to be successful,” says Foerster. The team think that this twist on the battle of the sexes is likely to occur in any species where there are physical differences between the male and female – perhaps including humans.
Moon recipe: smash planets and stir THE Earth and moon share a past etched in silicon, and it hints that the favoured theory of how the moon formed isn’t quite right. Most astronomers believe that the moon formed when a Marssized object struck Earth. If this is the case, the moon should contain mainly rock from the impacting body. However, Alex Halliday of the University of Oxford and his colleagues have evidence www.newscientist.com
suggesting that this isn’t so. The team studied the ratios of light to heavy isotopes of various elements in rock from the Earth, moon and meteorites. For most elements, the composition was the same, but samples from the Earth and moon showed a puzzling preference for the heavy forms of iron and silicon. The moon’s isotopic make-up was identical to Earth’s,
with no trace of an impacting object (Nature, vol 447, p 1102). Halliday thinks that the results support a modified giant impact theory proposed two years ago by Kaveh Pahlevan and Dave Stevenson of the California Institute of Technology, Pasadena. They suggested that the impact of a Mars-sized body first created a hot cloud of rock vapour. This mixed together as it cooled – obliterating any unique isotopic signatures of the impacting body – before forming the moon.
A PENGUIN big enough to look you in the eye is hardly what you’d expect to find in the tropics. But 36 million years ago, giant 1.5-metre penguins roamed the Peruvian coast. Large size in penguins is thought to be an adaptation to conserve body heat, so Mario Urbina of the National University of San Marcos in Lima was surprised to find that the giants, named Icadyptes salasi, lived in the tropics at a time when Earth was much warmer. The global cooling that covered Antarctica with ice sheets didn’t start until about 34 million years ago, 2 million years after Icadyptes had died out (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0611099104). “We don’t know how the large penguins would have thermoregulated on land,” says Julia Clarke of North Carolina State University in Raleigh. They probably spent most of their time in the water.
Deadly poisons meet their match RICIN, cholera toxin and shiga toxin, produced by deadly strains of E. coli, are the stuff of every poisoner’s handbook – because there is no antidote. Now Jose Saenz and colleagues at Washington University School of Medicine in St Louis, Missouri, may have found one. These toxins travel backwards through a cell’s protein-making pathway, passing through the Golgi network and endoplasmic reticulum before interrupting protein synthesis. Saenz’s team screened 14,400 small molecules for compounds that could halt this journey without disrupting normal cell function. They found two such molecules which, if safe, could lead to treatments for these poisons (Infection and Immunity, DOI: 10.1128/IAI.00442-07). 30 June 2007 | NewScientist | 19