Brown-led study rearranges some branches on animal tree of lifeMarch 06, 2008A study led by Brown University biologist Casey Dunn uses new genomics tools to answer old questions about animal evolution. The study is the most comprehensive animal phylogenomic research project to date, involving 40 million base pairs of new DNA data taken from 29 animal species. The study, which appears in Nature, settles some long-standing debates about the relationships between major groups of animals and offers up a few surprises. The big shocker: Comb jellyfish - common and extremely fragile jellies with well-developed tissues - appear to have diverged from other animals even before the lowly sponge, which has no tissue to speak of. This finding calls into question the very root of the animal tree of life, which traditionally placed sponges at the base. "This finding suggests either that comb jellies evolved their complexity independently from other animals, or that sponges have become greatly simplified through the course of evolution. If corroborated by other types of evidence, this would significantly change the way we think about the earliest multicellular animals," said Dunn, assistant professor of ecology and evolutionary biology at Brown. "Coming up with these surprises, and trying to better understand the relationships between living things, made this project so fascinating." Charles Darwin introduced the idea of a "tree of life" in his seminal book Origin of Species. A sketch of the tree was the book's only illustration. Nearly 150 years after its publication, many relationships between animal groups are still unclear. While enormous strides have been made in genomics, offering up a species' entire genome for comparison, there are millions of animal species on the planet. There simply isn't the time to sequence all these genomes. To get a better grasp of the tree of life - without sequencing the entire genomes of scores of species - Dunn and his team collected data, called expressed sequence tags, from the active genes of 29 poorly understood animals that perch on far-flung branches of the tree of life, including comb jellies, centipedes and mollusks. The scientists analyzed this data in combination with existing genomic data from 48 other animals, such as humans and fruit flies, looking for the most common genes being activated, or expressed. The aim of this new approach is to analyze a large number of genes from a large number of animals - an improvement over comparative genomics methods which allow for a limited analysis of genes or animals. The new process is not only more comprehensive, it is also more computationally intensive. Dunn's project demanded the power of more than 120 processors housed in computer clusters located in laboratories around the globe. Dunn and his team: * unambiguously confirmed certain animal relationships, including the existence of a group that includes invertebrates that shed their skin, such as arthropods and nematodes; * convincingly resolved conflicting evidence surrounding other relationships, such as the close relationship of millipedes and centipedes to spiders rather than insects; * established new animal relationships, such as the close ties between nemerteans, or ribbon worms, and brachiopods, or two-shelled invertebrates. "What is exciting is that this new information changes our basic understanding about the natural world - information found in basic biology books and natural history posters," Dunn said. "While the picture of the tree of life is far from complete after this study, it is clearer. And these new results show that these new genomic approaches will be able to resolve at least some problems that have been previously intractable." Brown University |
|||||||||||||||||||||
| Related Animal Species Current Events and Animal Species News Articles Wild pigs and deer do not spread GM corn via feces or accumulate transgenic residues in meat Deer stew, roast of wild boar, venison ragout - come fall, all varieties of game are in season for gourmets. However, ever since the worldwide surge in genetically modified corn, critical consumers' appetites have abated somewhat. CU-Boulder team identifies DNA barcodes to help track illegal trading of wildlife products Researchers from several institutions including the University of Colorado at Boulder have sequenced DNA "barcodes" for as many as 25 hunted wildlife species, providing information that can be used to better monitor the elusive trade of wildlife products, or bushmeat. Animal sacrifice in Brazilian folk religion Candomblé, a religion practiced primarily in South America and inspired by older African beliefs, makes much use of animal sacrifice. Researchers writing in BioMed Central's open access Journal of Ethnobiology and Ethnomedicine carried out interviews with priests, priestesses and adherents of the religion, documenting the role sacrifice plays in their beliefs. Key feature of immune system survived in humans, other primates for 60 million years A new study has concluded that one key part of the immune system, the ability of vitamin D to regulate anti-bactericidal proteins, is so important that is has been conserved through almost 60 million years of evolution and is shared only by primates, including humans - but no other known animal species. Biological clocks of insects could lead to more effective pest control Researchers at Oregon State University have discovered that the circadian rhythms or biological "clocks" in some insects can make them far more susceptible to pesticides at some times of the day instead of others. Researchers to study rebirth of an island after volcanic eruption When Alaska's Kasatochi Volcano erupted on Aug. 7, 2008, it virtually sterilized Kasatochi Island, covering the small Aleutian island with a layer of ash and other volcanic material several meters thick. Human language and dolphin movement patterns show similarities in brevity Two researchers from the Polytechnic University of Catalonia (UPC) and the University of Aberdeen in the United Kingdom have shown for the first time that the law of brevity in human language, according to which the most frequently-used words tend to be the shortest, also extends to other animal species. Researchers Look to Imprinted Genes for Clues to Fetal Growth Restriction in Cloned Swine Researchers at North Carolina State University have found that intrauterine growth restriction (IUGR), which results in low birth weight and long-term deleterious health effects in cloned swine, is linked to a type of gene - known as an imprinted gene - found only in placental mammals. Reduced diet thwarts aging, disease in monkeys The bottom-line message from a decades-long study of monkeys on a restricted diet is simple: Consuming fewer calories leads to a longer, healthier life. Battle of the sexes benefits offspring, says research Parents compensate for a lazy partner by working harder to bring up their offspring, but not enough to completely make up for the lack of parenting. More Animal Species Current Events and Animal Species News Articles |
|||||||||||||||||||||
|
|||||||||||||||||||||
|
|||||||||||||||||||||