| Bloodhound budgets Are speed records indulgent or are there big benefits? bbc.co.uk |
Florida panthers bound back thanks to Texas mates By LAURAN NEERGAARD 2010-09-23T19:34:37ZWASHINGTON (AP) -- In the quest to save the endangered Florida panther, their Texas cousins were the cat's meow. Wildlife biologists moved eight female panthers from Texas - close relatives yet genetically distinct - into south Florida 15 years ago in hopes of boosting reproduction, and the immigration paid off.... hosted.ap.org |
Nuclear receptors reveal glimpses into the evolution of complexity An international team of researchers charted the one billion year evolutionary course that a protein family followed, finding that today's novelty and complexity came about through many small changesDuring my lifetime, science and especially evolution, has been vigorously attacked by religious crackpots determined to inculcate humanity with their own unverifiable world view; that a supreme being specially created every living thing on earth. Yes, everything, even including mosquitoes, ticks, catholic priests and candirú -- those crazy Amazonian fish that swim into human penises and using their backward-facing spines, embed themselves into one's bladder. What sort of perverse supreme being would create such horrible creatures, anyway?But unlike kooks and wackaloons, who have an idiosyncratic sense of reality anyway, scientists rely upon solid, testable evidence to support their claims. To that end, proponents of "intelligent design" -- the modern incarnation of creationism -- have co-opted the use of words that sound scientific, hoping to deceive the public into accepting their beliefs as valid. For example, comparing proteins to intracellular "machines," IDists argue that there are so many complex molecular "machines" in cells that it boggles the mind to think they could have evolved de novo so many times. But did they?"[T]he fact is that most of these 'machines' are related to many other such 'machines' in the cell, and they are subtle variants on each other," said molecular archaeologist Joseph Thornton. Dr Thornton is an associate professor in the Center for Ecology and Evolutionary Biology at the University of Oregon in Eugene and an early career scientist for the Howard Hughes Medical Institute. "The complexity only had to evolve once, after which it was subtly altered by tinkering," said Dr Thornton. "But unless you really look under the hood of these proteins, the common template is obscured, and it appears that their complex functions had to evolve de novo in each one."Dr Thornton spearheaded an international team of researchers who "looked under the hood" at the template for a large and important family of proteins, the nuclear receptors (NRs). There are hundreds of different NRs and they regulate essential biological processes, such as development, metabolism and reproduction. They accomplish this by triggering the expression of specific genes in response to hormones, nutrients and other chemical signals. Many NRs are activated after binding to a specific hormone or other small molecule, known as a ligand, before they can bind DNA. However, some NRs function without the influence of a specific ligand, while others are incapable of activating gene expression, instead acting primarily as repressors by stopping the expression of particular genes. But which type of NR evolved first? The prevailing hypothesis is that the ancestral NR caused changes in the cell without having to bind a particular ligand first, suggesting that complexity -- the capacity to be regulated by chemical signals -- evolved independently in many lineages. But an alternative hypothesis suggests that the ancestral NR was a ligand-activated protein. This hypothesis, which has received scant attention, implies that minor evolutionary tinkering with the conserved ancestral type allowed NRs to respond to new molecular partners or, alternatively, to lose dependence on those partners after mutations that modified or degraded existing functions.To understand how the functional activity of NRs evolved, Dr Thornton's team searched GenBank and identified the DNA sequences, functions, and molecular structures of hundreds of NRs. Comparing these data, they used computers to extrapolate and reconstruct the biochemical characteristics of the ancestral NR, which first arose in the mists of time -- as long as a billion years ago, before all the different animal lineages evolved (figure):Contrary to the prevailing hypothesis, the team's computer analysis showed that the ancestral NR did require activation by a ligand. They also found that the underlying molecular mechanisms that allowed the ancestral protein to be activated by chemical signals were conserved in virtually all present-day NR descendants.The likely ancestor to all NRs arose before the earliest animal lineages, giving rise to two NRs in demosponges (see figure, above and also refer to photograph at top). Demosponges are simple, multicellular animals in the phylum porifera, which is the most basal of the animal groups and thus, is closest to the ancestral animal. The team tested the activity of the two demosponge NRs and found that they are activated by fatty acids, suggesting that the ancestral NR's ligand was probably also a fatty acid. Fatty acids are produced when fats are metabolised or broken down by the body. The researchers tinkered with the sponge NRs by making small changes that they predicted had followed the evolutionary changes to NR activity. They tested their predictions for how particular changes in the amino acids located in the ligand-binding pocket could change their mutant NR's binding character and function. As predicted, they found that some of their mutant NRs evolved partnerships with different hormones or other chemical signals after just a few changes that subtly affected the size and shape of the cavity where the signalling molecule binds. Other mutations made the NR structure more stable, removing the need for the protein to interact with a chemical signal before activating gene expression. These ligand-independent NRs are constitutive gene expression activators, like a light switch stuck in the "on" position. "Each body plan seems to be its own unrelated form, and how it might be possible to transform one form to another is mind-boggling," said Dr Thornton in an email message. "[But] when one identifies the underlying mechanisms for building these forms and reconstructs evolution vertically, tracing it through time from common ancestors, [then] the process of evolutionary transformation from a shared ancestral template becomes clear," said Dr Thornton. This idea also forms the core for research in developmental evolution, more commonly known as "evo-devo": the morphology of animals -- from jellyfish to fly to worm to fish to human -- are built using the same basic genetic toolkit, subtly reorganised and redeployed to build the wing of a fly or the limb of a human. "This is the protein version of this concept," explained Dr Thornton. "There is little true novelty in evolution, but remarkable creativity through the tinkering processes of mutation, selection and drift." "I find this issue interesting whether or not it's related to the controversy over intelligent design," added Dr Thornton. "It is about the nature of evolutionary creativity and the difficulty of seeing our own connections to our past." Sources:Bridgham, J., Eick, G., Larroux, C., Deshpande, K., Harms, M., Gauthier, M., Ortlund, E., Degnan, B., & Thornton, J. (2010). Protein Evolution by Molecular Tinkering: Diversification of the Nuclear Receptor Superfamily from a Ligand-Dependent Ancestor. PLoS Biology, 8 (10) DOI: 10.1371/journal.pbio.1000497Interview with Dr Joseph Thornton [email, 5 October 2010]GrrlScientistguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
Researchers react to news of funding freeze Britain's scientists and engineers will hear today how they have fared in the comprehensive spending review. We ask them for their reaction to the likely freezing of the science budgetPlease post your own reactions belowThe day of reckoning has arrived. This afternoon, George Osborne will lay out where the axe will fall across government departments, and the picture is likely to be a grim one for many in the public sector. Sources in the Department for Business, Innovation and Skills tell me that the £4.6bn spent each year on scientific research will be maintained and ringfenced for the next four years, a cut in real terms of around 10% in the science budget taking account of inflation. The capital expenditure budget - a further £1.4bn - is not protected, and could be halved. The full impact of this may not be clear for some time.In recent months and weeks, the science budget has been fiercely defended by researchers and supporters of science. Those in DBIS I spoke with said that science got its act together and put a strong case. I'm told that both the business secretary, Vince Cable, and the science minister, David Willetts, negotiated hard with the Treasury to limit the depth of cuts to science.The chancellor's speech is due to begin at 12.30pm, but my colleague Andrew Sparrow has already begun live blogging the spending review and will push on through until the end of the day. Evan Harris, a former MP and Liberal Democrat science spokesman, has written a blog on how to judge the spending review here. He advises we avoid jumping for joy until the fat lady has sung. I will be gathering reactions to the announcement from researchers and campaign groups and posting them in the comments below, but do please join in with your own thoughts on what the cuts mean. We can only expect an overall figure for the science budget today. It could take months for Cable's team to work out how the money is allocated between the research councils, the national academies, the Higher Education Funding Council for England (which funds university research) and other bodies. Adrian Smith, the Business, Innovation and Skills director general for research, will be advising Cable on this. This is a crucial process, as it will shed light on the fields of research that the government wants to prioritise. The bottom line is that it could be some time before researchers in a particular field know how well - or not - their area has fared.Science funding crisisScience policySpending review 2010Ian Sampleguardian.co.uk © Guardian News & Media Limited 2010 | Use of this content is subject to our Terms & Conditions | More Feeds guardian.co.uk |
World congress explores soil-borne disease More than 260 scientists and researchers from 16 countries are in Townsville in north Queensland this week as part of the sixth World Melioidosis Congress. abc.net.au |