tag:blogger.com,1999:blog-108309222024-03-08T13:12:33.018-06:00The Evolution ProjectDocumenting evolutionary biology being usedJosh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.comBlogger398125tag:blogger.com,1999:blog-10830922.post-1155233026834406702006-08-10T12:58:00.000-05:002006-08-10T13:03:46.960-05:00Ohio HOPEA few days ago we mentioned a new group in Ohio that will be helping promote pro-science candidates for the Ohio Board of Ed, and especially helping to bust "Ohio's answer to Connie Morris." Well, <a href="http://www.ohiohope.org">HOPE has webpage</a> now, so you can click over there and help support their important work.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com38tag:blogger.com,1999:blog-10830922.post-1155153519283007532006-08-09T14:53:00.000-05:002006-08-09T14:58:39.396-05:00How western Kansas became K-State country, and how we can make it evolution country<a href="http://www2.ljworld.com/news/2006/aug/08/ku_country/">KU Country? | LJWorld.com</a>:<br /><br /><blockquote>Craig Miner’s latest book, “Next Year Country: Dust to Dust in Western Kansas, 1890-1940,” was featured in Monday’s Journal-World. In the book, Miner, a history professor at Wichita State University, chronicles the peaks and valleys of western Kansas, where harsh weather often spelled the difference between success and failure for the agricultural economy.<br /><br />While compiling the history, Miner turned up several clues about why residents of the western two-thirds of the state have a good feeling about K-State. The school set up experiment stations across the area to test crop varieties and develop new hybrids that were resistant to pests and drought.<br /><br />K-State, the railroads and the local Farm Bureaus took information on the road, traveling to different cities giving lectures and sharing information about better agriculture techniques for men and home economics for women.</blockquote>I see nothing to suggest that a similar strategy, reaching out to the more distant communities and showing the value of science and evolutionary biology to people in rural Kansas couldn't bring the western part of the state as firmly onto the side of Darwin as they are of the Wildcats.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1131416485984535872005-11-07T20:21:00.000-06:002005-11-07T20:21:26.006-06:00Request for helpI haven't had the time to deal with TEP lately, but I hate to see it languish. Would anyone like to help me out?Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128498456650721442005-10-05T02:47:00.000-05:002005-10-05T02:47:36.650-05:00678: The Living Worlds HypothesisIn <a href="http://www.astrobio.net/news/modules.php?op=modload&name=News&file=article&sid=1720&mode=thread&order=0&thold=0">this interview</a> David Grinspoon posits a hypothesis about the way life could have evolved on Titan. It's a testable hypothesis.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128497946523689302005-10-05T02:39:00.000-05:002005-10-05T02:39:06.523-05:00677: A Prize Bug<a href="http://www.corante.com/loom/archives/2005/10/03/a_prize_bug.php">A Prize Bug</a>:<br /><blockquote>As scientists got to know the global variation of Helicobacter better, they began to discover a remarkable pattern. They mapped out an evolutionary tree of the strains of the bacteria and found that it lined up very well with the migrations of humans over the past 50,000 years. One study looked at the Ladakh province of northern India. Muslims and Buddhists have coexisted there for 1000 but remain isolated from one another. It turns out that Muslim Ladakhs only carry a European strain of Helicobacter, while Buddhists carry a mix of European and East Asian bugs. In Peru, Indians who have lived in relative isolation from European colonists carry Helicobacter that is akin to the bugs in East Asia, a major source of migration into the New World. Peruvians from the cities, on the other hand, carried European Helicobacter. It appears that Helicobacter existed in our species before humans began to move beyond Africa, and was then carried around the world as our ancestors traveled the globe. But exactly how long ago this parasite first made its home in us remains to be discovered.<br /><br />Scientists have a long way to go in order to understand the full evolutionary story of Helicobacter. Many ethnic groups have yet to be sampled, and the evolutionary contortions of their bacteria have yet to be documented. This work promises to offer some guidance about what we should do about this remarkable bug. Antibiotics can wipe it out, but that doesn't necessarily mean we should eradicate it from our species. It produces some proteins that kill other microbes, and one study suggested that it reduces the chances of children getting diarrhoea. Other studies have suggested that while Helicobacter causes some kinds of cancer, not having it increases the chances of other kinds. It's possible that a long coevolution has made Helicobacter part parasite, part mutualist--much the same as intestinal worms may have prevented our ancestors from getting allergies. It's even possible that Helicobacter's high-speed evolution allowed it to become more parasitic in some parts of the world and more mutualistic in others. Before we decide on its future, it will serve us well to understand Helicobacter's past.</blockquote>This is the bacterium that won Marshall and Warren this year's Nobel Prize. Understanding its evolution gives insight into the diseases it causes and prevents, and our own species' history.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128497721403728372005-10-05T02:35:00.000-05:002005-10-05T02:35:21.403-05:00676: Fitting in: Newly evolved genes adopt a variety of strategies to remain in the gene pool<a href="http://www.pandasthumb.org/archives/2005/10/fitting_in_newl.html">The Panda's Thumb: Fitting in: Newly evolved genes adopt a variety of strategies to remain in the gene pool</a>:<br /><blockquote>To determine the basis for the persistence of functional gene duplicates in the genome, three scientists at the Institute of Molecular Systems Biology at the Swiss Federal Institute of Technology in Zürich have collaborated on the largest systematic analysis of duplicated gene function to date. Using an integrative combination of computational and experimental approaches, they classified duplicate pairs of genes involved in yeast metabolism into four functional categories: (1) back-up, where a duplicate gene copy has acquired the ability to compensate in the absence of the other copy, (2) subfunctionalization, where a duplicate copy has evolved a completely new, non-overlapping function, (3) regulation, where the differential regulation of duplicates fine-tunes pathway usage, and (4) gene dosage, where the increased expression provided by the duplicate gene copy augments production of the corresponding protein.<br /><br />Their results, which appear in the October issue of the journal Genome Research, indicate that no single role prevails but that all four of the mechanisms play a substantial role in maintaining duplicate genes in the genome.</blockquote>Gene duplication is a major source of novel material for evolution.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128497527374607752005-10-05T02:32:00.000-05:002005-10-05T02:32:07.376-05:00675: The words of the world<a href="http://www.pandasthumb.org/archives/2005/10/the_words_of_th.html">The Panda's Thumb: The words of the world</a>:<br /><blockquote>A study in Science has returned biological methods to linguistic evolution in a reversal of history, and concluded that one can, within limits, reconstruct the history of language.<br /><br />Charles Darwin was not the first person to suppose that historical evolution could be recognised by homologies and represented by tree diagrams. That honour goes to Sir William Jones in 1797, although the tree idea was later.<br /><br />Jones argued that one could compare cognate terms and infer a historical relationship between languages and this has become the foundation of modern philology. For example, words that are based on the idea of “knowing” (including, as it happens, “idea”) generate a tree of Indo-European languages. [And like biological evolution, there are “creationists” who think that all language was created in Sanskrit.]<br /><br />Now, a study in Science has returned biological methods to linguistic evolution in a reversal of history, and come up with some interesting conclusions.</blockquote>Evolution gives insight into linguistics.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128497374626678592005-10-05T02:29:00.000-05:002005-10-05T02:29:34.626-05:00674: New dolphin species discovered<a href="http://evolvethought.blogspot.com/2005/10/new-dolphin-species-discovered-in-my.html">New dolphin species in Australia.</a>Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128497271365297582005-10-05T02:27:00.000-05:002005-10-05T02:27:51.366-05:00673: How A Zebra Lost Its Stripes: Rapid Evolution Of The Quagga<a href="http://www.sciencedaily.com/releases/2005/09/050928084511.htm">How A Zebra Lost Its Stripes: Rapid Evolution Of The Quagga</a>:<br /><blockquote>In the past, the quagga has alternatively been described as a species and a subspecies of the Plains zebra.These researchers asked how and when the quagga diverged from all the remaining related horses, zebras, and asses. They compared the genetics, coat color and habitats of existing zebras with related extinct species.<br /><br />The mitochondrial DNA markers from 13 museum specimens, including the only skeleton in museum collections, which is at Yale's Peabody Museum of Natural History, showed that quagga likely diverged from Plains zebra about 120,000 to 290,000 years ago during the Ice Age. These results suggest that the quagga descended from a population of plains zebras that became isolated and the distinct quagga body type and coloring evolved rapidly.<br /><br />This study reveals that the Ice Age was important not just in Europe and North America, but also in Africa.<br /><br />"The rapid evolution of coat color in the quagga could be explained by disrupted gene flow because of geographical isolation, an adaptive response to a drier habitat, or a combination of both of the two forces," said Caccone.</blockquote>Thanks to <a href="http://mcdougald.blogspot.com/2005/09/darwin-and-quagga.html">afarensis</a> for the tip.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128497097160500912005-10-05T02:24:00.000-05:002005-10-05T02:24:57.206-05:00672: Autoimmune overload may damage HIV-infected brain | Science Blog<a href="http://www.scienceblog.com/cms/autoimmune_overload_may_damage_hiv-infected_brain_9005">Autoimmune overload may damage HIV-infected brain | Science Blog</a>:<br /><blockquote>Researchers studying the evolution of the human immunodeficiency virus (HIV) in the brain have found that the body's own defenses may cause HIV-related dementia.<br /><br />Publishing in the Sept. 2005 issue of the Journal of Virology, the researchers show that HIV in the temporal lobe mutates at a rate 100 times faster than in other parts of the body, triggering white blood cells to continually swarm to attack the infection. The associated overcrowding and inflammation appear to cause the dementia.<br /><br />Earlier studies had suggested that the build-up of white blood cells could lead to HIV-related dementia, but this is the first study to track the probable mechanism.<br /><br />The findings could lead to new treatments that target HIV-infected white blood cells, perhaps one day countering the brain wasting that will affect as many as 15 percent of the nearly 40 million people around the world who are infected with the virus.</blockquote>Evolution, saving lives.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1128487239803707492005-10-04T23:40:00.000-05:002005-10-04T23:40:39.856-05:00671: Save the Flowers<a href="http://www.sciencenews.org/articles/20050924/bob10.asp">Save the Flowers: Science News Online, Sept. 24, 2005</a>:<br /><blockquote>No one knows what's responsible for this waning of fragrance by roses and other ornamental-flower varieties, including carnations and chrysanthemums, but scientists who investigate floral scent suspect that the flower breeding that's led to an estimated 18,000 rose cultivars in an ever-widening spectrum has run roughshod over fragrance.<br /><br />"Pigment compounds are derived from the same biochemical precursors [as scent compounds are], so it makes sense that if you make more of one you get less of the other," notes floral-scent biochemist and geneticist Eran Pichersky of the University of Michigan in Ann Arbor.<br /><br />Floral scent may be dwindling because breeders for the $30 billion ornamental-flower industry pay scant attention to this most emblematic attribute of flowers.</blockquote>Evolution is a story of trade-offs. This is a testable evolutionary hypothesis.<br /><br />Thanks to <a href="http://www.boingboing.net/2005/09/29/beautiful_flowers_lo.html">BoingBoing</a> for the tip.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com2tag:blogger.com,1999:blog-10830922.post-1127950956148067002005-09-28T18:42:00.000-05:002005-09-28T18:42:36.186-05:00644-670: Evolutionary Game Theory<a href="http://mahalanobis.twoday.net/stories/1008595/">A few words on Evolutionary Game Theory</a>:<br /><blockquote>About a month ago, Michael asked me to give my opinion on an article on cheating viruses and game theory. Coincidentally, I had to write a referee report on a paper about evolutionary game theory (EGT) only recently, so I have collected further material and ideas about this topic which I would like to share with you:<br /><br />Jörgen Weibull's paper "What have we learned from Evolutionary Game Theory so far?" provides a great non-technical introduction to EGT. It gives a first idea of what EGT is all about. I very much appreciated the reference list of this paper as well. In Evolutionary game dynamic, Josef Hofbauer and Karl Sigmund dig a little deeper and provide some interesting insights into the relationship between systems of differential equations (inclusions) and special equilibrium refinements (notable ESS and ES). Finally, I would like to draw your attention to Daniel Friedman's paper "On economic applications of evolutionary game theory". This paper is also non-technical and its objective is to make the general ideas behind an evolutionary game theoretic model more tranparent. As the title suggests, Friedman gives a nice outline of how these ideas can be incorporated into economic models.</blockquote>Links are omitted, but click through and check out the ways that evolutionary logic is used by economists.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1127785578176466922005-09-26T14:06:00.000-05:002005-09-26T20:46:18.176-05:00643: Insight into our sight: A new view on the evolution of the eye lensVia <a href="http://darwin.bc.asu.edu/blog/?p=532">Stranger Fruit</a>, <a href="http://www.eurekalert.org/pub_releases/2005-09/cp-iio092105.php">Insight into our sight: A new view on the evolution of the eye lens</a>:<br /><blockquote>Fish, frogs, birds and mammals all experience image-forming vision, thanks to the fact that their eyes all express crystallins and form a lens; however, the vertebrates' nearest invertebrate relatives, such as sea squirts, have only simple eyes that detect light but are incapable of forming an image. This has lead to the view that the lens evolved within the vertebrates early in vertebrate evolution, and it raises a long-standing question in evolutionary biology: How could a complex organ with such special physical properties have evolved?<br /><br />In their new work, Shimeld and colleagues approached this question by examining the evolutionary origin of one crystallin protein family, known as the ß?-crystallins. Focusing on sea squirts, invertebrate cousins of the vertebrate lineage, the researchers found that these creatures possess a single crystallin gene, which is expressed in its primitive light-sensing system. The identification of the sea squirt's crystallin strongly suggests that it is the single gene from which the vertebrate ß?-crystallins evolved.<br /><br />The researchers also found that, remarkably, expression of the sea squirt crystallin gene is controlled by genetic elements that also respond to the factors that control lens development in vertebrates: The researchers showed that when regulatory regions of the sea squirt gene are transferred to frog embryos, these regulatory elements drive gene expression in the tadpoles' own visual system, including the lens. This strongly suggests that prior to the evolution of the lens, there was a regulatory link between two tiers of genes: those that would later become responsible for controlling lens development, and those that would help give the lens its special physical properties. This combination of genes appears to have then been co-opted in an early vertebrate during the evolution of its visual system, giving rise to the lens.</blockquote>Common descent, testable evolutionary predictions and evaluating evolutionary hypotheses. Cool.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1127785570703412652005-09-26T13:01:00.000-05:002005-09-26T20:47:12.696-05:00642: Evolving modularity<a href="http://johnhawks.net/weblog/2005/09/21#modular_evolution_circuits_kashtan_2005">John Hawks explains Why organisms are modular</a>. Very neat simulations by Kashtan and Alon on the evolution of circuits in varying environment.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com1tag:blogger.com,1999:blog-10830922.post-1127149031214161332005-09-19T11:57:00.000-05:002005-09-19T11:57:11.276-05:00641: Researchers Find How Malaria Parasite Disperses From Red Blood Cells | Science Blog<a href="http://www.scienceblog.com/cms/researchers_find_how_malaria_parasite_disperses_from_red_blood_cells_8935">Researchers Find How Malaria Parasite Disperses From Red Blood Cells | Science Blog</a>:<br /><blockquote>Researchers at the National Institute of Child Health and Human Development have determined the sequence in which the malaria parasite disperses from the red blood cells it infects. The National Institute of Child Health and Human Development is one of the National Institutes of Health.<br /><br />…<br /><br />“It’s extremely important to learn about all aspects of the malaria parasite’s life cycle, ” said Duane Alexander, M.D., Director of the NICHD. “The parasite is growing resistant to the drugs used to treat it, and new information is essential for developing strategies to protect against the disease.”</blockquote>Evolution is at work in the resistance to drugs, but also explains how the parasite is so well adapted to parasitism.<br /><!-- technorati tags start --><p style="text-align:right;font-size:10px;">Technorati Tags: <a href="http://www.technorati.com/tag/evolution" rel="tag">evolution</a></p><!-- technorati tags end -->Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1127103438614261512005-09-18T23:17:00.000-05:002005-09-18T23:17:18.660-05:00640: Stressed Cells Spark DNA Repair Missteps And Speed EvolutionThanks to <a href="http://mcdougald.blogspot.com/2005/09/evolution-of-complex-protein-machines.html">afarensis</a> for point out <a href="http://www.sciencedaily.com/releases/2005/09/050916080112.htm">Stressed Cells Spark DNA Repair Missteps And Speed Evolution</a>:<br /><blockquote>When Dr. Susan Rosenberg, professor of molecular and human genetics at Baylor College of Medicine, first published her finding that the mutation rate increased in bacteria stressed by starvation, sometimes resulting in a rare change that benefited the bacteria, it was controversial.<br /><br />In a report in the current issue of the journal Molecular Cell, she and her colleagues describe not only how it happens but also show that this only occurs at a special time and place in the stressed cells.</blockquote>Research on evolution that reveals how cancer works, how the body fights it, and how new mutations arise.<br /><!-- technorati tags start --><p style="text-align:right;font-size:10px;">Technorati Tags: <a href="http://www.technorati.com/tag/evolution" rel="tag">evolution</a></p><!-- technorati tags end -->Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1127081342117200792005-09-18T17:08:00.000-05:002005-09-18T17:09:02.116-05:00639: Mitochondrial DNA adaptations in living human populations<a href="http://johnhawks.net/weblog/2005/09/18#ruiz-pesini_selection_mtdna_2004">Mitochondrial DNA adaptations in living human populations</a>:<br /><blockquote>populations in northern latitudes today are enriched for a number of mtDNA haplogroups that are likely adaptive to cold. Today, these haplogroups (as a class) are largely protective against degenerative diseases of aging, possibly because they reduce oxygen free radical production. But they are also more susceptible to disorders of energy metabolism, because they reduce ATP production.<br /><br />Needless to say, this says some interesting things about the relationship of longevity and energy metabolism in recent human populations.</blockquote>Human evolution and the trade-offs between longevity and energy efficiency.<br /><!-- technorati tags start --><p style="text-align:right;font-size:10px;">Technorati Tags: <a href="http://www.technorati.com/tag/evolution" rel="tag">evolution</a></p><!-- technorati tags end -->Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1127081031441383232005-09-18T17:03:00.000-05:002005-09-18T17:03:51.526-05:00638: Part Human, Part Virus<a href="http://www.corante.com/loom/archives/2005/09/15/part_human_part_virus.php">Part Human, Part Virus: Corante > The Loom ></a>:<br /><blockquote>Here’s the history as they now see it: the free-living, oxygen-breathing ancestors of mitochondria were infected with some nasty T3/T7 viruses. Most of the time the viruses were fatal. But some mutant tried to replicate itself inside a proto-mitochondrion and failed. Its genes were trapped in the genome of its host. Its host was able to reproduce, and one of its descendants took up residence inside the cell of a eukaryote. At some point after this merger, a mutation caused the virus’s DNA and RNA copying genes to come back online. They took over the job of making these molecules, and the mitochondria’s own genes for this job were later stripped out of its genome.</blockquote>Viruses, endosymbionts, and the evolution of eukaryotes.<br /><!-- technorati tags start --><p style="text-align:right;font-size:10px;">Technorati Tags: <a href="http://www.technorati.com/tag/evolution" rel="tag">evolution</a></p><!-- technorati tags end -->Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1126758025427936482005-09-14T23:20:00.000-05:002005-09-14T23:20:25.486-05:00637: For Fossil Hunters, Gobi Is No Desert - New York Times<a href="http://www.nytimes.com/2005/09/13/science/13gobi.html?ei=5088&en=7ada78abdb73dbe7&ex=1284264000&partner=rssnyt&emc=rss&pagewanted=all">For Fossil Hunters, Gobi Is No Desert - New York Times</a>:<br /><blockquote>It has been the paleontologists' boast, never disputed, that this particular forbidding stretch of the Gobi holds the world's richest and most diverse deposits of dinosaur and early mammal remains from 80 million years ago, a critical time for life in the Cretaceous geologic period.<br /><br />Four years had passed since paleontologists of the American-Mongolian expedition last pitched camp at Ukhaa Tolgod ("brown hills" in Mongolian), scene of their greatest triumphs. They were lured back last month, as surely as gold prospectors to the mother lode, by the expectation that the site has more to yield.</blockquote>Hunting early fossils. Evolution at work.<br /><!-- technorati tags start --><p style="text-align:right;font-size:10px;">Technorati Tags: <a href="http://www.technorati.com/tag/evolution" rel="tag">evolution</a></p><!-- technorati tags end -->Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1126735950446547272005-09-14T17:12:00.000-05:002005-09-14T17:12:30.446-05:00636: Immune system has evolved to prevent autoimmune disease | Science Blog<a href="http://www.scienceblog.com/cms/immune_system_has_evolved_to_prevent_autoimmune_disease_8884">Immune system has evolved to prevent autoimmune disease | Science Blog</a>:<br /><blockquote>New research finds the human immune system has foregone evolutionary changes that would allow it to produce better antibodies in less time because the improved antibodies would be far more likely to attack the body's own tissues. The Rice University study finds the immune system has evolved a near-perfect balance for producing antibodies that are both effective against pathogens and unlikely to cause autoimmune disease.<br /><br />The findings will be published in the journal Physical Review Letters. They are based on a new model of the immune system that is the first to simulate the hierarchical nature of the body's immune response. The model predicts that chronic infections may lead to autoimmune diseases, a scenario that has been proposed as a cause of some rheumatic diseases like arthritis.</blockquote>Mmmm, evolution. There are constraints on evolution and our immune system is (clearly) not perfect.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1126735857882233532005-09-14T17:10:00.000-05:002005-09-14T17:10:57.883-05:00635: How bodies and plants repair UV damaged DNA | Science Blog<a href="http://www.scienceblog.com/cms/how_bodies_and_plants_repair_uv_damaged_dna_8885">How bodies and plants repair UV damaged DNA | Science Blog</a>:<br /><blockquote>For the first time, researchers have observed exactly how some cells are able to repair DNA damage caused by the sun's ultraviolet (UV) radiation.<br /><br />The Ohio State University study revealed how the enzyme photolyase uses energy from visible light to repair UV damage.<br /><br />This enzyme is missing in all mammals, including humans, although all plants and all other animals have it. Greater understanding of how photolyase works could one day lead to drugs that help repair UV damage in human DNA.<br /><br />…<br /><br />Scientists believe that all placental mammals lost the ability to make this enzyme some 170 million years ago, said Zhong, an assistant professor of physics and adjunct assistant professor of chemistry and biochemistry at Ohio State.<br /><br />That's why humans, mice, and all other mammals are particularly vulnerable to cancer-causing UV rays from the sun. But the rest of the animal kingdom – insects, fish, birds, amphibians, marsupials, and even bacteria, viruses and yeast – retained a greater ability to repair such damage.</blockquote>Common descent!Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1126735554336675092005-09-14T17:05:00.000-05:002005-09-14T17:05:54.336-05:00634: In Chimpanzee DNA, Signs of Y Chromosome's Evolution - New York Times<a href="http://www.nytimes.com/2005/09/01/science/01chimp.html?ex=1283227200&en=8d7073d0343ce531&ei=5088&partner=rssnyt&emc=rss">In Chimpanzee DNA, Signs of Y Chromosome's Evolution - New York Times</a>:<br /><blockquote>Scientists have decoded the chimp genome and compared it with that of humans, a major step toward defining what makes people human and developing a deep insight into the evolution of human sexual behavior.<br /><br />Scientists sequenced the DNA of a chimpanzee named Clint and compared it with that of humans.<br /><br />The comparison pinpoints the genetic differences that have arisen in the two species since they split from a common ancestor some six million years ago.<br /><br />The realization that chimpanzees hold a trove of information about human evolution and nature comes at a time when they and other great apes are under harsh pressures in their native habitat. Their populations are dwindling fast as forests are cut down and people shoot them for meat. They may soon disappear from the wild altogether, primatologists fear, except in the few sanctuaries that have been established.<br /><br />Chimpanzees and people possess almost identical sets of genes, so the genes that have changed down the human lineage should hold the key to what makes people human.</blockquote>Common descent and human evolution!Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1126735099259681992005-09-14T16:58:00.000-05:002005-09-14T16:58:19.303-05:00633: Brain May Still Be Evolving, Studies Hint - New York Times<a href="http://www.nytimes.com/2005/09/09/science/09brain.html?ei=5088&en=d8f1aaeff4ecf407&ex=1283918400&adxnnl=1&partner=rssnyt&emc=rss&adxnnlx=1126278467-Jx2QJ+4mibfjKVNR2CSUrA">Brain May Still Be Evolving, Studies Hint - New York Times</a>:<br /><blockquote>Two genes involved in determining the size of the human brain have undergone substantial evolution in the last 60,000 years, researchers say, leading to the surprising suggestion that the brain is still undergoing rapid evolution.<br /><br />The discovery adds weight to the view that human evolution is still a work in progress, since previous instances of recent genetic change have come to light in genes that defend against disease and confer the ability to digest milk in adulthood.<br /><br />It had been widely assumed until recently that human evolution more or less stopped 50,000 years ago.</blockquote>This surprises no one, in fact. I've got a stack of cases where humans are evolving, ranging from lactose intolerance to mutations which conferred protection against the Plague and now protect some people against HIV.<br /><br />Don't read this to mean that particular alleles necessarily are "genetically smarter" or anything like that. It may mean that or it may not, all they are showing is change, another name for evolution.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0tag:blogger.com,1999:blog-10830922.post-1124731776021611462005-08-22T12:29:00.000-05:002005-08-22T12:29:36.706-05:00632: The Tubercular Hominid<a href="http://www.corante.com/loom/archives/2005/08/22/the_tubercular_hominid.php">The Tubercular Hominid: Corante > The Loom ></a>:<br /><blockquote>French researchers have found that people in Djibouti carry strains of TB that are significantly different than anything seen before. They have many more genetic differences than have been found in human TB strains from anywhere else in the world. Yet they are more closely related to other human TB than to the Mycobacterium species that infect cattle and other animals. The scientists then turned the mutations of the Djibouti strains into a molecular clock. They estimate that the ancestor of today's human TB existed some three million years. The <a href="http://pathogens.plosjournals.org/static_sites/plospathogens/10.1371_journal.ppat.0010005-S.pdf">results</a> have just been published in the new open access journal PLOS Pathogens.<br /><br />If tuberculosis was infecting our ancestors three million years ago, it was infecting early, small-brained hominids. All of the hominids known from that time lived in Africa, and hominids would not be found outside the continent for over a million years. Our own species is believed to have evolved much later in Africa, and to have spread to Asia and Europe roughly 50,000 years ago. So it's telling that all these ancient strains are found in Africa, not far from some of the richest lodes of hominid fossils in Ethiopia. The genetic diversity of these bacteria reflects the genetic diversity of living Africans.</blockquote>The evolution of TB.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com1tag:blogger.com,1999:blog-10830922.post-1124381861263536882005-08-18T11:17:00.000-05:002005-08-18T11:17:41.456-05:00631: Worm ideal model for studying viruses in humans | Science Blog<a href="http://www.scienceblog.com/cms/node/8706">Worm ideal model for studying viruses in humans | Science Blog</a>:<br /><blockquote>For years researchers throughout the world have studied C. elegans because many aspects of its biology, such as genetics, development and the workings of neurons, mirror the biology of humans. However, no viruses were known to infect the millimeter-long roundworm so it was not used as a model for studying viral infections.<br /><br />The Nature paper now shows that UC Riverside researchers have developed a strain of the worm, C. elegans, in which an animal virus could replicate, allowing them to map the delicate dance of action and reaction between virus and host.<br /><br />The UCR team has shown that virus replication in the worm triggers an antiviral response known as RNA silencing or RNA interference (RNAi). RNAi specifically breaks down the virus’ RNA. Virus RNA creates proteins that allow the virus to function. The virus responds by producing a protein acting as a suppressor of RNAi to shut down the host’s antiviral response. Virus infection did not occur when the viral RNAi suppressor was made inactive by genetic mutations in the host system.<br /><br />C. elegans’ RNAi system is considered a “blanket system,” meaning that it has parallels in humans, making the worm model discovered by Ding and his colleagues a valuable tool in studying the way viruses interact with hosts. This tool may speed the discovery of treatments for virus-caused diseases that plague humans.<br /><br />“The RNAi machinery is very similar between humans and C. elegans, and human viruses such as Influenza A virus and HIV are known to produce RNAi suppressors,” Ding said. “So now, the question is can we treat human viral diseases using chemical inhibitors of viral RNAi suppressors?”</blockquote>Common descent and the evolutionary arms race between viruses and their hosts.Josh Rosenauhttp://www.blogger.com/profile/07304209937998935215noreply@blogger.com0