Initiation Zone vs Nested Discontinuity Models

"Interestingly, phylogenetic data suggest that the specific attributes of the eukaryal machinery could date back to an archaeal ancestor containing a rudimentary form of chromatin structure. Since nucleosomes form only on double stranded DNA, greater symmetry of the ancestral eukaryal/archaeal replication fork could facilitate the emergence of chromatin structure. "

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Forgotten by evolution? Stem Cells

Max Planck Society - Press Release: "The Max Planck researchers have two possible explanations for their results. On one hand, the stem cells could be missing some factor which is absolutely necessary for the complete differentiation into specialised cells and tissue. On the other hand, it could be the case that at least some of the known adult stem cell types are 'only' the rudiments of earlier embryonal differentiation processes, or even dispersed leftovers from previous evolutionary stages. Indeed, these cells are still showing plasticity which is a characteristic of stem cells, but no direct physiological function can be deduced from it."

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Biologists Discover New Pathway Into Plant Cells

Biologists Discover New Pathway Into Plant Cells: "Also of considerable interest is that the biological mechanism discovered here bears striking similarity to the way proteins can function in mammalian cells - scientists say they may have found a characteristic that has been preserved for more than 600 million years, when plants and animals diverged from a common ancestor on their separate evolutionary paths."

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06.24.2005 - Revueltosaurus skeleton unearthed at Petrified Forest upsets dinosaur tale

06.24.2005 - Revueltosaurus skeleton unearthed at Petrified Forest upsets dinosaur tale: "Dinosaurs are divided into two main groups, the ornithischians and saurischians, both of which, based on fossil finds, appeared to arise in the Late Triassic, between 225 and 200 million years ago. The early ornithischians were thought to have evolved into animals such as the stegosaurs of the Jurassic and the frilled and duck-billed dinosaurs of the Cretaceous, while the saurischians split into the sauropodomorphs - the long-necked browsers like Brachiosaurus - and the carnivorous theropods, like T. rex. Only the theropods survive to the present as birds."

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Technique Offers New View Of Dynamic Biological Landscape

Technique Offers New View Of Dynamic Biological Landscape: "The E-MAP technique consists of selectively 'dialing down' the activity of a multitude of gene pairs and comparing the effects of those changes to those that result when each gene is dialed down individually. Many genes' activity could be reduced by eliminating them entirely, but for the subset of genes that are essential for yeast growth -- whose complete deletion would kill the cell -- the researchers invented a high throughput technique to manipulate the half-life of their messenger RNA (mRNA). Since mRNA is a genetic intermediate during the conversion of a gene to protein, reducing its lifespan by mutating the mRNA message lowers the amount of protein the cell can produce. The group called this approach 'decreased abundance by mRNA perturbation' (DAmP). "

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Ribosome and RNA world

11.03.2005 - New X-rays of cell's ribosome could lead to better antibiotics: "Ribosomes are found in all organisms, ranging from bacteria to humans, and probably arose nearly 2 billion years ago. They have changed so little through evolution that a bacterial ribosome can often translate human genes into protein. Some people suspect that ribosomes, which at their core consist of ribonucleic acid (RNA), a sister of the DNA that comprises our genes, arose when RNA, not DNA, carried our genetic dowry."

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archaeon Sulfolobus solfataricus

Transcriptional response to DNA damage in the archaeon Sulfolobus solfataricus -- Salerno et al. 31 (21): 6127 -- Nucleic Acids Research: "Genomic sequencing has revealed the presence of archaeal genes homologous to components of the eucaryal nucleotide excision repair (NER) pathway, which is involved in the repair of ultraviolet (UV) light-induced DNA damage. However, the events involved in the cell response to UV irradiation and their regulation have not been studied in Archaea. We show here that UV radiation induces the formation of cyclobutane pyrimidine dimers (CPDs) in the hyperthermophilic archaeon Sulfolobus solfataricus, and that these lesions are efficiently repaired in vivo in the dark, suggesting that a NER pathway is active. DNA damage is a signal for concomitant growth arrest and transcriptional induction of the NER genes XPF, XPG and XPB. The cell response to UV irradiation includes transcriptional regulation of genes encoding two DNA binding proteins involved in chromosome dynamics. Moreover, several of these genes are also strongly induced by the intercalating agent actinomycin D. Thus, response to DNA damage in S.solfataricus has features essentially conserved in all three domains of life. "

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10.27.2005 - Picky female frogs drive evolution of new species in less than 8,000 years

10.27.2005 - Picky female frogs drive evolution of new species in less than 8,000 years: "The yet-to-be- named species arose after two isolated populations of the green-eyed tree frog reestablished contact less than 8,000 years ago and found that their hybrid offspring were less viable. To avoid hybridizing with the wrong frogs and ensure healthy offspring, one group of females preferentially chose mates from their own lineage. Over several thousand years, this behavior created a reproductively isolated population - essentially a new species - that is unable to mate with either of the original frog populations."

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Godless Origins

Gray Matters
Adeistic
Avidity
Eine Kleine Nattermusing
eMusings
eVolition
Galaria
Godspell Follies
MetaThoughts
Mimble Wimble
Naturalism
Neologisms
palimpsest
Sechuam
Sintheist
Tabula Flexuosa
Weltschauung

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o

Archea & Eubacteria . Cancer . Cell Biology . Complex Systems . Cyanobacteria . Diagrams & Tables . Endosymbiosis . Enzymes . Evo Devo . Evolution . Evolutionary Algorithms . Evolution in Action . Fat . Geology . Galaria . Glossary . Godspell Follies . Immunology . Life Chemistry . Medical Science . Mechanisms of Evolution . Mimble Wimble . Molecule . Molecular Biology . Molecular Paths . Organics . Origin of Life . Paleogeology . Pathways . Photosynthesis . Protein . Receptor . Rocks & Minerals . SET . Signaling . Sleep . Stem & Progenitor Cells . Stromatolites . Taxonomy Phylogeny . Tissue . Virus .

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Item links

Items
~ In the Beginning was Abiogenesis ~ Before the Beginning ~ Miller-Urey & Beyond
~ CHONSP and RNA world ~ The evolution of the prebiotic atmosphere ~ Primordial Soup : Theories ~ Top Down & Bottom Up ~ Minimal Molecules ~ Minimal Genome ~ Archaea
~ Illogical Deceit theory ~ RNA world ~ protein catalysts and ribozymes ~ A primordial RNA modification enzyme: the case of tRNA (m1A) methyltransferase. ~ genome and proteome
~ Evidence Found for Origin of Genes ~ mtDNA ~ Ancient DNA ~ DNA evolutionary connections ~ evolution and organogenesis ~ Darwin ~ Darwin in the Galapagos
~ MicroRNAs Have Shaped The Evolution Of The Majority Of Mammalian Genes ~ Diversity
~ Selection ~ Analyses of physiological evolutionary response. ~ Multi-Level Selection
~ optimization ~ Logic & Science ~ Neo-Darwinism ~ Stephen Jay Gould ~ Computer Modeling
~ PLoS Genetics: The Evolutionary Value of Recombination Is Constrained by Genome Modularity ~ Evolutionary Distance Analysis & Maximum Parsimony Analysis ~ Tree of Life
~ Tree of Life or Fuzzy Bush of Life ~ Comparing Gene Trees and Genome Trees: A Cobweb of Life? ~ Genomes and the Tree of Life ~ Protozoa ~ Horizontal Gene Transfer in Prokayotes
~ Protists in Evolution, and Symbiogenesis ~ Proterozoic and Archaean ~ Prokaryote Systematics: The Evolution of a Science

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