all Daniel L. Hartl stories

Deadliest form of malaria is younger than previously believed

70652986 — Mon, 26 Mar 2007 05:14:16 -0400

Malaria kills more people than any other communicable disease except for tuberculosis. It is the world's most serious parasitic tropical disease, resulting in 1 million to 3 million deaths annually. The most lethal form of malaria, Plasmodium falciparum, accounts for the majority of infections, 200 million to 300 million annually. Now researchers from the Harvard-Oxford Malaria Genome Diversity Project have linked the origin of the P.falciparum parasite to a single ancestor of more recent origin than previously thought.

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New gene found in fruit flies could impact human medicine

70652986 — Mon, 26 Mar 2007 05:07:17 -0400

In one type of fruit fly, Drosophilia melanogaster, but not in others, researchers found a gene that carries instructions for making a motor that gives this species' sperm extra horsepower. The researchers were not looking specifically for such a gene but came across it serendipitously during a general investigation of motor proteins. Various creatures boast these proteins, which make it possible for them to get around in salt water or fresh water, or in a reproductive canal, by lashing or spinning threadlike tails. "The tail of D. melanogaster's sperm is twice as long as the fly itself," researcher Daniel Hartl points out. "Other fruit flies may have tails as long as 20 times their body length, intricately coiled inside their sex organs until ready for use.

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What killed the dinosaurs?

70652986 — Mon, 26 Mar 2007 05:11:13 -0400

Charles Marshall's childhood passion led him to a career in paleontology, trying to understand the interplay between inheritance, environment, and catastrophe in directing evolution. Marshall's work attracted media attention in 1996. He and University of Washington geologist Peter Ward concluded there may have been other causes than just the well-publicized comet or asteroid impact responsible for the extinctions at the end of the Cretaceous Period, when all living dinosaur species died out. Marshall used a statistical analysis of the fossil record to conclude that a major drop in sea level – preceding the impact by 150,000 to 300,000 years – may have led to as much as 25 percent of the huge number of extinctions that took place.

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