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[ Evidence Of Darwinian Selection Still Influencing Human Evolution ]

Evidence Of Darwinian Selection Still Influencing Human Evolution

New evidence proves humans are continuing to evolve and that significant natural and sexual selection is still taking place in our species in the modern world. Despite advancements in medicine and technology, as well as an increased prevalence of monogamy, research reveals humans are continuing to evolve just like other species. Scientists in an international collaboration, which includes the University of Sheffield, analysed church records of about 6, 000 Finnish people born between 1760-1849 to determine whether the demographic, cultural and technological changes of the agricultural revolution affected natural and sexual selection in our species. Project leader Dr Virpi Lummaa, of the University's Department of Animal and Plant Sciences, said: "We have shown advances have not challenged the fact that our species is still evolving, just like all the other species 'in the wild'.

New Insight Into Molecular Motor Movement

Molecular motors are the key to the development of higher forms of life. They transport proteins, signal molecules and even entire chromosomes down long protein fibers, components of the so-called cytoskeleton, from one location in the cell to another. Not unlike trucks on a motorway, there are permanently thousands of these small motor proteins underway at any given point in time - a highly coordinated and extremely fast mode of transport. This highly efficient infrastructure is a prerequisite for the formation of large, complex cells and multicellular organisms. Bacteria, for example, lack this foundation, because they possess neither molecular motors nor cytoskeletons. Kinesins represent one class of such molecular motors. They run along microtubules comprising 13 individual fibers arranged in a tube form.

Anti-Superbug Clues In Deep, Isolated Cave

A deep, isolated cave in New Mexico harbors strains of antibiotic-resistant bacteria that might hold clues for fighting modern-day superbugs. The hope is the discovery means there are previously unknown antibiotics occurring naturally, that could be used to treat infections. Researchers from McMaster University, in Hamilton, Ontario, Canada, and the University of Akron, in Akron, Ohio, USA, write about their findings in the 11 April online issue of PLoS ONE. Resistance to antibiotics among bacteria is giving rise to superbugs like methicillin-resistant Staphylococcus aureus ( MRSA ), and a growing concern for human health. In extreme cases the bacteria are resistant to all drugs and the only option left to deal with the infection is surgery. An important question for research is where and how these organisms acquire their resistance.

Genetically Modified Animals For Use In Scientific Research

Researchers reporting in the journal Cell, a Cell Press publication, have devised a new and improved method for producing genetically modified animals for use in scientific research. The method relies on haploid embryonic stem cells (haESCs) instead of sperm to artificially fertilize immature egg cells. Such stem cells are similar to sperm in that they carry only genetic material from a mouse "dad." Not only will the advance make it easier to produce genetically modified mice, but it may also enable genetic modification of animals that can't be modified by today's means. The technique might ultimately be used in assisted human reproduction for those affected by genetic disease, the researchers suggest. "The current procedure to generate genetically modified animals is tedious and very inefficient, " said Jinsong Li of the Shanghai Institute for Biological Sciences.

Morphogen Theory Questioned

New York University biologists have discovered new mechanisms that control how proteins are expressed in different regions of embryos, while also shedding additional insight into how physical traits are arranged in body plans. Their findings, which appear in the journal Cell, call for reconsideration of a decades-old biological theory. The researchers investigated a specific theory - morphogen theory, which posits that proteins controlling traits are arranged as gradients, with different amounts of proteins activating genes to create specified physical features. This theory was first put forth in the 1950s by mathematician and World War II code breaker Alan Turing and refined in the 1960s by Lewis Wolpert. It has been used to explain why a tiger has stripes, among other phenomena. But some biologists have raised questions about the theory, which contends that physical features are necessarily tied to absolute concentrations of proteins within the morphogen gradient.


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