NatureNews: Great Ape Census in Africa
The first ever pan African great ape survey aims to get an accurate estimate of chimpanzee populations remaining in the wild.
Nature: Science in Africa – View from the Frontline
Kenya: In search of talent
Kenyan science is a study in contrasts. Among sub-Saharan nations, it ranks third — behind South Africa and Nigeria — in its output of scientific papers published in international journals, and its publishing outranks that of economic heavyweight Nigeria in fields such as environment, ecology and immunology. It is also a hub of collaborations on the continent (see ‘Country connections’). But Kenya’s research output has grown more slowly than most other sub-Saharan nations. In the recent African Union survey, Kenya scored last in terms of the increase in the numbers of published research papers, normalized for population size.
Most of the scientific work in Kenya is centred in government-owned research institutes that have extensive international collaborations. Among the most renowned is the Kenya Medical Research Institute (KEMRI), which has centres around the country and does basic research as well as developing drugs, vaccines and products such as diagnostic kits for HIV — an important service because Kenya lacks a thriving private sector for commercialization of research. KEMRI has a budget of $37.5 million, with 45% coming from its international collaborators, including the Wellcome Trust, a London-based medical research charity.
Other centres also stand out, such as the Kenya Agricultural Research Institute, headquartered in Nairobi, which has an international reputation for its work on crops and agricultural diseases. And the Kenya Marine and Fisheries Research Institute, headquartered in Mombasa, has a programme focused on mangrove research that is considered the best in sub-Saharan Africa.
By contrast, the universities suffer from lack of infrastructure and money. The government and donors have focused on boosting primary and secondary education, but have neglected universities, say observers.
The government invested only $3.6 million in 2010 on university-based research, according to Shaukat Abdulrazak, secretary of the National Council for Science and Technology. And there is a shortage of professors to serve a student population that grew from 90,000 in 2004 to more than 120,000 in 2008.
Nature: The Wheat Stalker
Njoro, Kenya (Jun 30, 2011) — David Cheruiyot noticed that his wheat fields were turning the wrong colour. The stems of the plants took on a sickly brown hue, and when he peeled open the heads there was no grain inside. “If you go to inspect it, there is nothing but dust,” he recalls.
Ug99, a virulent fungus that causes a disease called stem rust, arrived on Cheruiyot’s farm in Kenya in 2007. It devastated wheat fields in the country that season, slashing yields by as much as 80% in some regions. Since that epidemic, Cheruiyot has sprayed his wheat three times a season with fungicide, something that few farmers in Africa can afford.
Online collection.
Stem rust has plagued farmers for millennia, but Ug99 is a new superstrain that overcomes defensive genes in 90% of the wheat crops planted around the globe. Since it was first detected in 1998, spores of the fungus have spread from East Africa into Yemen and Iran. If the disease continues its march eastwards, hitting the breadbaskets of south Asia and China, it will threaten the food supply of hundreds of millions of people.
Better biosurveillance could halt disease spread
Joined-up approach would have helped in German E. coli outbreak.
Germany is still recovering from one of the world’s worst outbreaks of enterohaemorrhagic Escherichia coli, which as of 18 June had sickened more than 3,200 people and caused 39 deaths1. The unusually deadly bacteria moved undetected through the food supply from livestock to agriculture to the dinner table, and the response to the outbreak was branded slow and inefficient by physicians and scientists (see ‘Microbe outbreak panics Europe‘).
Now a group of health professionals assembled by the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, has called for biosurveillance efforts in the United States and worldwide to be streamlined to help recognize and respond to threats quickly.
“We are trying to create an international immune system, a system that has the capacity to recognize abnormalities,” says Ian Lipkin, co-chair of the National Biosurveillance Advisory Subcommittee (NBAS) and director of the Center for Infection and Immunity at the Mailman School of Public Health at Columbia University, New York.
A last push to eradicate polio
Funding gap persists as agencies and organizations attempt to wipe out the tenacious virus.
Some 99% of wild poliovirus has been eradicated, but it clings on in a few places. The last endemic hot spots are the conflict-ridden front lines of Pakistan and Afghanistan, areas of India and Nigeria — and governments and charities are scrambling to eliminate it entirely.
Bill Gates, the Microsoft co-founder and co-chair of the Bill & Melinda Gates Foundation headquartered in Seattle, Washington, announced in his annual letter yesterday his commitment to eradicate polio by 2012, by giving the vaccine to all children under five in poor countries. The initiative is led by the Gates Foundation and the World Health Organization’s (WHO) Global Polio Eradication Initiative (GPEI), which includes among other organizations Rotary International, a non-profit foundation headquartered in Evanston, Illinois.
Nature examines the challenges that remain before the virus can be wiped out.
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Evolution: A One-Way Street
Since Darwin, evolution has been in vogue. Most scientists take it on principle that accumulation of mutations in DNA over million of years leads to new life forms.
But a question that has intrigued researchers for some time is whether organisms can go back to their ancestral forms. Is evolution is reversible? Conventional wisdom—known in the sphere of evolutionary biology as “Dollo’s law” after pre-eminent dinosaur researcher Louis Dollo—says no. A recent study published in the journal Nature has elegantly confirmed that evolution is a one-way street by studying the process at the molecular level.
As evolution occurs, the changes are so intricate that it becomes nearly impossible for the organism to go back to its original form. Freshwater fishes that live in a dark cave will lose their eyesight over generations. Even if a landslide creates an opening in the cave and lets in some sunshine, it is highly unlikely that the eye will reform.
Dollo’s theory has remained mostly unchallenged, except for a few works that say that evolution is reversible. In 2003, a team of scientists said that they’d found a species of snail that had regained its ability to coil into a loop after having lost the trait in previous generations.
“But their methods were unreliable,” said Boris Igic, a professor of biology at the University of Illinois in Chicago who was not affliated with the study. The snails could either have gone back to their original genetic makeup, or they could have gained new proteins that give it the old coiling.
The problem was that there was no real test to prove these theories. Evolution of organisms takes millions of years, making it difficult for scientists to make any direct observations.
Joseph Thornton, a biology professor at the University of Oregon, and his colleagues went around the problem by examining a single protein that helps humans and vertebrates cope with stress.
Millions of years ago, a fish existed that lacked bones. It is the ancestor to most life forms on earth today. That fish contained a small protein called the glutocorticoid receptor, which became active in the presence of two distinct hormones.
Over the course of the next 40 million years, the receptor evolved and became more specific such that it activated in the presence of only a single hormone—cortisol. It had accumulated 37 changes, but only seven were necessary to make it into the new receptor.
The researchers wanted to find out whether evolution could reverse at the level of the protein. To do so, they reversed the seven changes.
“But to our surprise, we got a dead receptor when we reversed,” said Thornton.
They found that the only way to make the protein reverse completely was to make five extra changes. These five fine-tuned the receptor, but did not give it a new function.
The probability of all five of these changes getting reversed is highly unlikely since they don’t confer a new advantage to the organism. They act like brakes that have to be removed to make evolution a two-way street.
Once the scientists fixed these five, they found that making the seven key changes reversed the protein to the ancestral form. They called the five brakes “ratchets” that prevented reverse evolution.
“This is not to say that the ancestral function cannot be re-acquired,” said Igic. But the function will come from forward evolution rather than a reversal. When whales evolved from a four-legged terrestrial ancestor, they evolved new proteins that resulted in fins. It was a reversal in function toward an ancestor of tetrapods that could swim, but in biochemistry, it was a movement forward.
Natural selection can take numerous paths during evolution but once those paths are chosen, reversal is highly unlikely. This is the first study of its kind, but Thornton does not expect this to be a rare case.
That an experiment at the molecular level can deliver a decisive conclusion about higher-order evolution is testament to the elegance of life.
“Everything that makes us who we are is stored in DNA,” said Ortlund, a biochemistry professor at Emory University, and co-author of the study. “Changes at the macroscopic scale have to start at the molecular level.”