Genetics

Monkeflower Mutation Provides Evolution Insight

Publication: National Geographic News   Date: November 12, 2003   View Article

For years scientists have grappled to understand the number and type of genetic mutations required for a new species to evolve. Does it require the accumulation of many minute mutations? Or can a single mutation spark a big change?

Now researchers studying pink and red flowers in the monkeyflower (Mimulus) family have found a persuasive answer: A single mutation can recruit a whole new set of pollinators, serving as the fork in the road that leads to a new species.

Did Galapagos Turtle Lineage Survive Ancient Blast?

Publication: National Geographic News   Date: October 2, 2003   View Article

About 100,000 years ago the top of Volcano Alcedo in the Galápagos Islands exploded in a violent eruption that smothered the region in pumice and blew away all but one lucky lineage of the giant tortoises that lived there, according to a new study.

“The only lineage that probably survived the eruption was the one that repopulated the region,” said Luciano Beheregaray, a molecular ecologist at Macquarie University in Sydney, Australia.

Female Moa Birds Liked the Little Guys, Studies Suggest

Publication: National Geographic News   Date: September 11, 2003   View Article

Female moa birds had a sweet spot for the little guys, according to two papers appearing in the September 11 issue of Nature.

The research teams, led by scientists in New Zealand and England, applied a pioneering technique in genetic analysis that allowed them to determine the sex of extinct moa by analyzing nuclear DNA extracted from fossils.

Rocky Mountains Separate Canadian Lynx, Study Says

Publication: National Geographic News   Date: September 3, 2003   View Article

The Canadian lynx (Lynx canadensis) may creep for miles through dense, debris-strewn forest for the chance to pounce on a scarce snowshoe hare (Lepus americanus), but the stealthy feline is apparently seldom bothered to weather a crossing of the Rocky Mountains to find a mate.

Evolutionary ecologist Nils Chr. Stenseth together with geneticists Kjetill Jakobsen and Eli Rueness at the University of Oslo in Norway, and colleagues from Canada and Sweden, performed a large-scale genetic analysis of the elusive cat throughout its North American habitat and found populations of genetically distinct animals.

Chilean Mystery Blob Identified as Sperm Whale Skin

Publication: National Geographic News   Date: August 25, 2003   View Article

A mysterious, 41-foot by 19-foot (12.4-meter by 5.4-meter) gelatinous mass of flesh that washed ashore in southern Chile this June came from a sperm whale (Physeter macrocephalus), not a giant octopus (Octopus giganteus) as some sleuths suspected.

“Two independent DNA analyses confirmed the identification as belonging to a sperm whale,” said Elsa Cabrera, director of the Center for Cetacean Conservation in Santiago, Chile.

Big Trouble for Asia’s Giant Catfish

Publication: National Geographic News   Date: May 15, 2003   View Article

This time of year, fishers along the banks of the Mekong River in the village of Chiang Khong in northern Thailand wait expectant, as they have for hundreds of years, for the arrival and harvest of giant catfish. But this year the catfish may never come.

“No fish have been captured in Thailand since 2001 and the giant catfish is in danger of disappearing from Thailand completely,” said Zeb Hogan, a fisheries biologist at the University of California at Davis.

Cannibalism Normal for Early Humans?

Publication: National Geographic News   Date: April 10, 2003   View Article

Genetic markers commonly found in modern humans all over the world could be evidence that our earliest ancestors were cannibals, according to new research. Scientists suggest that even today many of us carry a gene that evolved as protection against brain diseases that can be spread by eating human flesh.

© 2008-2010 Collected Writings By John Roach