Bar Code of Life: DNA Tags Help Classify Animals
Posted on November 12, 2008 in Global warming definition
Wandering the aisles of a supermarket several years ago, one of us (Hebert) marveled at how the store could keep track of the array of merchandise simply by examining the varying order of thick and thin lines that make up a product’s barcode. Why, he mused, couldn’t the unique ordering of the four nucleic acids in a short strand of DNA be mined in a similar way to identify the legions of species on earth? Ever since Carl Linnaeus began systematically classifying all living things 250 years ago, biologists have looked at various features--color, shape, even behavior--to identify animals and plants. In the past few decades, researchers have begun to apply the genetic information in DNA to the task. But both classical and modern genetic methods demand great expertise and eat up huge amounts of time. Using just a small section of the DNA--something more akin to the 12-digit barcode on products--would require far less time and skill. [More] The X Chromosome and the Case against Monogamy Researchers report genetic evidence bolstering the socially contentious idea that polygyny--the mating practice where some males dominate reproduction by fathering children with several women--was the norm for sexual behavior throughout human history and prehistory. Because polygyny means other men father few or no children, the study, published today in PLoS Genetics, also shows that, on average, women bequeath more genes to their offspring than men do. [More]
Climate change may be sparking new and bigger "dead zones"
Posted on October 15, 2008 in Global warming
“Wasteland” conjures up visions of dusty desolation where life is fleeting and harsh--if it exists at all. Oceans, too, have their inhospitable pockets. Scientists are discovering that climate change--and not just fertilizer from farm use--may be spurring the emergence of barren underwater landscapes in coastal waters. Expanding dead zones not only spell trouble for biodiversity, but they also threaten the commercial fisheries of many nations. Dead zones are not new; they form seasonally in economically vital ecoystems worldwide, including the Gulf of Mexico and Chesapeake Bay. Agricultural runoff sparks many of these die-offs; increased use of nitrogen fertilizers has doubled the number of lifeless pockets every decade since the 1960s, resulting in 405 dead zones now dotting coastlines globally. [More] Bar Code of Life: DNA Tags Help Classify Animals Wandering the aisles of a supermarket several years ago, one of us (Hebert) marveled at how the store could keep track of the array of merchandise simply by examining the varying order of thick and thin lines that make up a product’s barcode. Why, he mused, couldn’t the unique ordering of the four nucleic acids in a short strand of DNA be mined in a similar way to identify the legions of species on earth? Ever since Carl Linnaeus began systematically classifying all living things 250 years ago, biologists have looked at various features--color, shape, even behavior--to identify animals and plants. In the past few decades, researchers have begun to apply the genetic information in DNA to the task. But both classical and modern genetic methods demand great expertise and eat up huge amounts of time. Using just a small section of the DNA--something more akin to the 12-digit barcode on products--would require far less time and skill. [More]