Shiver Me Piglets!
By Catherine Scullion
New findings published by a team from the University of Uppsala in Sweden, pinpoint a genetic cause of the shivering of newborn piglets cooed over in petting zoos and barns across the country.
Most newborn mammals are kept warm by a reaction in the mitochondria involving brown fat tissue; which converts fats into heat. Pigs lack this mechanism and so shudder in order to maintain their body temperature.
The new results assert the difference to be caused by loss of function of the gene encoding Uncoupling Protein (UCP) 1. mRNA to be translated into the protein has not been transcribed in an ancestor of the modern domestic pig for the past 20 million years.
UCP1 is a key component of the aforementioned heat producing process. Neither this protein nor brown fat tissue has been found in domesticated pigs. Leif Anderson, director of the project, is pleased that the findings can be neatly used in the context of evolutionary theory. "A reasonable explanation for this is that brown fat was not essential during a period in the evolution of pigs, when it lived in a warm climate." The wild boar is the only known ancestor of the domestic pig known to live in a cold climate. Apparently in compensation for loss of UCP1 and brown fat these animals make dens to provide a warmer microclimate for their young.
Such facts are evidence of dynamic interaction between biological processes of an animal and its environment. Traits not essential for survival are often irretrievably lost, other measures can then develop according to environmental pressures
To Andersson the study is one of many which highlights weakness in the 'intelligent design' hypothesis which continues to gain support in America. The team found four different mutations in the gene, any of these is sufficient to preclude UCP1 production.
"If a creator happened to make a mistake with the UCP1 gene in the pig, why four different mistakes when one would have been enough to disrupt gene function." This is further endorsed by the identification of identical mutations in closely related species. It doesn't really seem like the work of an omnipotent, all knowing creator; though everyone has their off-days I suppose.
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