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Treating animals like molecules aids census
In brief– Sun, skin and the Cleaning cages makes a meal of lab rats’ own young wrong set of genes
GUNNAR KNECHTEL/LAIF/CAMERA PRESS
18 | NewScientist | 24 May 2008
AS THE old adage has it, cleanliness is next to godliness, but it also has sinister consequences for lab rats: they are much more likely to cannibalise their young if their cages are frequently cleaned. Charlotte Burn at the University of Oxford and Georgia Mason at the University of Guelph in Ontario, Canada, found that nearly twice as many pups were eaten in cages cleaned twice a week as in those cleaned fortnightly (Applied Animal Behaviour Science, DOI: 10.1016/ j.applanim.2008.02.005).
Cannibalism was most likely if the cages were cleaned soon after the pups were born. Burn notes that cannibalism in rodents is not unusual; mothers sometimes eat unhealthy young to conserve energy for raising healthy ones. But while this might be normal behaviour, it could be disruptive in a research context The findings suggest that cleaning their cages disrupts the rats’ ability to recognise their kin, according to Volker Rudolf at Rice University in Houston, Texas. Burn says that scent is the key to
rats being able to recognise their pups. She suggests minimising the handling of very young pups to avoid interfering with the scents that bond their parents to them. It is also important, she says, to avoid introducing foreign scents into the rats’ cages. For example, lab technicians should avoid handling several rats one after another. Finally, Burn advises, cleaning the rats’ cages should not “stress the parents with loud noises or physical disturbance”. FRANK COURTES/AGNCE VU
RED hair, freckles and pale skin make you sun sensitive, but genes, not pigmentation, may be the ultimate guide to who is most likely to get skin cancer after sitting in the sun. Genes for light hair and skin and the risk of skin cancer tend to go hand in hand. For instance, the same mutations in a gene called MC1R that cause red hair and freckles also greatly increase the chances of getting melanoma if you sunbathe. But not all such genes are equally affected by sunlight. Researchers led by Karí Stefánnson of Decode Genetics in Reykjavik, Iceland, have identified a mutation in a gene called ASIP that, like MC1R, is linked to red hair and freckles and increases the likelihood of getting skin cancer (Nature, DOI: 10.1038/ng.161). Interestingly, though, this ASIP variant doubles the risk of melanoma even in sunstarved Icelanders, indicating that its skin cancer effect is less dependent on sunlight than MC1R ’s. “In Iceland you can avoid sunlight because it is so rare,” says Stefánnson. In contrast, his team found that having the MC1R variant had little effect on Icelandic people’s risk of developing skin cancer, indicating that its effect was highly dependent on exposure to sunlight. “It doesn’t look like it’s just pigmentation,” agrees geneticist Stuart MacGregor of the Queensland Institute of Medical Research in Brisbane, Australia.
Treat a hippo like a gas molecule HOW many pygmy hippos are left in the wild? It’s hard to estimate numbers of elusive animals, but a new census method should make it possible to uncover the secrets of even the shyest. Conservation biologists use automatic cameras triggered by infrared sensors to record the presence of animals such as pygmy hippos or deer that tend to flee or hide from humans. With most species, though, it is impossible to tell whether the camera is recording a few individuals many times or many individuals a few times. Now Marcus Rowcliffe at the Institute of Zoology in London and his colleagues have adapted equations for the random motion of gas molecules to help them estimate the population density of a species from the frequency with which animals are photographed. The only other information they need is how fast the animals move. The researchers tested their method in an animal reserve on two species of deer and a type of wallaby, and found the population sizes calculated matched the actual populations in the park (Journal of Applied Ecology, DOI: 10.1111/j.1365-2664.2008.01473.x).
Alps are no go without snow FOR skiers and snowboarders there is no business like snow business. But in the Alps winter sports may be doing no business at all in years to come. In the late 1980s, there was a dramatic step-like drop in the amount of snow falling in the Swiss Alps. Since then, snowfall has never recovered, and in some years the amount that fell was 60 per cent lower than was typical in the early 1980s, says Christoph Marty at the Swiss Federal Institute for Snow and Avalanche Research in Davos. He has analysed snowfall trends spanning 60 years and adds that the average number of
snow days over the last 20 winters is lower than at any time since records began more than 100 years ago. The future of winter tourism in the region is looking grim. “I don’t believe we will see the kind of snow conditions we have experienced in past decades,” he says. Previous studies have suggested a decline in the region’s snowfall but Marty’s analysis is the first to take in 10 years of new data from 34 stations between 200 and 1800 metres above snow level. The work will appear in Geophysical Research Letters. It’s hard say whether this marks any kind of tipping point in terms of climate change, says Marty. “But from the data it looks like a change in the large-scale weather pattern,” he adds.
www.newscientist.com
GUNNAR KNECHTEL/LAIF/CAMERA PRESS
18 | NewScientist | 24 May 2008
AS THE old adage has it, cleanliness is next to godliness, but it also has sinister consequences for lab rats: they are much more likely to cannibalise their young if their cages are frequently cleaned. Charlotte Burn at the University of Oxford and Georgia Mason at the University of Guelph in Ontario, Canada, found that nearly twice as many pups were eaten in cages cleaned twice a week as in those cleaned fortnightly (Applied Animal Behaviour Science, DOI: 10.1016/ j.applanim.2008.02.005).
Cannibalism was most likely if the cages were cleaned soon after the pups were born. Burn notes that cannibalism in rodents is not unusual; mothers sometimes eat unhealthy young to conserve energy for raising healthy ones. But while this might be normal behaviour, it could be disruptive in a research context The findings suggest that cleaning their cages disrupts the rats’ ability to recognise their kin, according to Volker Rudolf at Rice University in Houston, Texas. Burn says that scent is the key to
rats being able to recognise their pups. She suggests minimising the handling of very young pups to avoid interfering with the scents that bond their parents to them. It is also important, she says, to avoid introducing foreign scents into the rats’ cages. For example, lab technicians should avoid handling several rats one after another. Finally, Burn advises, cleaning the rats’ cages should not “stress the parents with loud noises or physical disturbance”. FRANK COURTES/AGNCE VU
RED hair, freckles and pale skin make you sun sensitive, but genes, not pigmentation, may be the ultimate guide to who is most likely to get skin cancer after sitting in the sun. Genes for light hair and skin and the risk of skin cancer tend to go hand in hand. For instance, the same mutations in a gene called MC1R that cause red hair and freckles also greatly increase the chances of getting melanoma if you sunbathe. But not all such genes are equally affected by sunlight. Researchers led by Karí Stefánnson of Decode Genetics in Reykjavik, Iceland, have identified a mutation in a gene called ASIP that, like MC1R, is linked to red hair and freckles and increases the likelihood of getting skin cancer (Nature, DOI: 10.1038/ng.161). Interestingly, though, this ASIP variant doubles the risk of melanoma even in sunstarved Icelanders, indicating that its skin cancer effect is less dependent on sunlight than MC1R ’s. “In Iceland you can avoid sunlight because it is so rare,” says Stefánnson. In contrast, his team found that having the MC1R variant had little effect on Icelandic people’s risk of developing skin cancer, indicating that its effect was highly dependent on exposure to sunlight. “It doesn’t look like it’s just pigmentation,” agrees geneticist Stuart MacGregor of the Queensland Institute of Medical Research in Brisbane, Australia.
Treat a hippo like a gas molecule HOW many pygmy hippos are left in the wild? It’s hard to estimate numbers of elusive animals, but a new census method should make it possible to uncover the secrets of even the shyest. Conservation biologists use automatic cameras triggered by infrared sensors to record the presence of animals such as pygmy hippos or deer that tend to flee or hide from humans. With most species, though, it is impossible to tell whether the camera is recording a few individuals many times or many individuals a few times. Now Marcus Rowcliffe at the Institute of Zoology in London and his colleagues have adapted equations for the random motion of gas molecules to help them estimate the population density of a species from the frequency with which animals are photographed. The only other information they need is how fast the animals move. The researchers tested their method in an animal reserve on two species of deer and a type of wallaby, and found the population sizes calculated matched the actual populations in the park (Journal of Applied Ecology, DOI: 10.1111/j.1365-2664.2008.01473.x).
Alps are no go without snow FOR skiers and snowboarders there is no business like snow business. But in the Alps winter sports may be doing no business at all in years to come. In the late 1980s, there was a dramatic step-like drop in the amount of snow falling in the Swiss Alps. Since then, snowfall has never recovered, and in some years the amount that fell was 60 per cent lower than was typical in the early 1980s, says Christoph Marty at the Swiss Federal Institute for Snow and Avalanche Research in Davos. He has analysed snowfall trends spanning 60 years and adds that the average number of
snow days over the last 20 winters is lower than at any time since records began more than 100 years ago. The future of winter tourism in the region is looking grim. “I don’t believe we will see the kind of snow conditions we have experienced in past decades,” he says. Previous studies have suggested a decline in the region’s snowfall but Marty’s analysis is the first to take in 10 years of new data from 34 stations between 200 and 1800 metres above snow level. The work will appear in Geophysical Research Letters. It’s hard say whether this marks any kind of tipping point in terms of climate change, says Marty. “But from the data it looks like a change in the large-scale weather pattern,” he adds.
www.newscientist.com