Nosso cérebro é como 100 bilhões de minicomputadores todos funcionando sincronizados: mero acaso, fortuita necessidade ou design inteligente???

quinta-feira, outubro 18, 2018

Cell
Article| Volume 175, ISSUE 3, P643-651.e14, October 18, 2018


Enhanced Dendritic Compartmentalization in Human Cortical Neurons

Lou Beaulieu-Laroche, Enrique H.S. Toloza, Marie-Sophie van der Goes, Matthew P. Frosch, Sydney S. Cash, Mark T. Harnett5

Source/Fonte: New Scientist

Highlights

• Direct electrical recordings to compare human and rat cortical dendrites
• Longer human dendrites exhibit increased electrical compartmentalization
• Reduced ion channel densities in human dendrites
• Compartmentalization alters the input-output properties of human neurons

Summary

The biophysical features of neurons shape information processing in the brain. Cortical neurons are larger in humans than in other species, but it is unclear how their size affects synaptic integration. Here, we perform direct electrical recordings from human dendrites and report enhanced electrical compartmentalization in layer 5 pyramidal neurons. Compared to rat dendrites, distal human dendrites provide limited excitation to the soma, even in the presence of dendritic spikes. Human somas also exhibit less bursting due to reduced recruitment of dendritic electrogenesis. Finally, we find that decreased ion channel densities result in higher input resistance and underlie the lower coupling of human dendrites. We conclude that the increased length of human neurons alters their input-output properties, which will impact cortical computation.

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Campanha de Bolsonaro aplica seu próprio viés político à educação???

terça-feira, outubro 16, 2018

“Quando você iguala ciência e ideologia, você anda para trás, ignora séculos de aprendizado”, diz Luiz Davidovich, presidente da Academia Brasileira de Ciências. “A teoria da evolução não é ideológica. É resultado de percepções científicas e foi testada ao longo do tempo.”

in Campanha de Bolsonaro aplica seu próprio viés político à educação.

Davidovich cometeu dois erros:

1. A teoria da evolução é sim ideológica - quem disse foi Darwin em uma de suas cartas que pelo menos ele tinha dado um chega pra lá no criacionismo; 
2. A teoria da evolução foi testada em nível microevolutivo, macroevolutivo, não! A descendência com modificação ao longo do tempo, por exemplo. Nunca explicaram a Explosão Cambriana. Quais são os mecanismos evolucionários? De A a Z? Qual a origem da informação genética? Por que do upgrade para a Síntese Evolutiva Ampliada/Estendida com aspectos neolamarckistas porque a Síntese Evolutiva Moderna já era em 1980 uma teoria científica falida que posava de ortodoxia científica somente nos livros-texto??? 

Sim, a teoria da evolução deve continuar sendo ensinada em nossas escolas, mas deve ser ensinada objetiva e honestamente considerando as evidências a favor e contra. Do jeito que a teoria da evolução é ensinada no Brasil, não é educação, mas doutrinação ideológica do materialismo filosófico que posa como se fosse ciência!

Como a geologia conta a história dos gargalos evolutivos e da vida na Terra

AstrobiologyVol. 18, No. 9 Hypothesis ArticlesFree Access
Geological and Geochemical Constraints on the Origin and Evolution of Life
Norman H. Sleep
Published Online:12 Sep 2018 https://doi.org/10.1089/ast.2017.1778
 
 Source/Fonte: Nature - NASA

Abstract

The traditional tree of life from molecular biology with last universal common ancestor (LUCA) branching into bacteria and archaea (though fuzzy) is likely formally valid enough to be a basis for discussion of geological processes on the early Earth. Biologists infer likely properties of nodal organisms within the tree and, hence, the environment they inhabited. Geologists both vet tenuous trees and putative origin of life scenarios for geological and ecological reasonability and conversely infer geological information from trees. The latter approach is valuable as geologists have only weakly constrained the time when the Earth became habitable and the later time when life actually existed to the long interval between ∼4.5 and ∼3.85 Ga where no intact surface rocks are known. With regard to vetting, origin and early evolution hypotheses from molecular biology have recently centered on serpentinite settings in marine and alternatively land settings that are exposed to ultraviolet sunlight. The existence of these niches on the Hadean Earth is virtually certain. With regard to inferring geological environment from genomics, nodes on the tree of life can arise from true bottlenecks implied by the marine serpentinite origin scenario and by asteroid impact. Innovation of a very useful trait through a threshold allows the successful organism to quickly become very abundant and later root a large clade. The origin of life itself, that is, the initial Darwinian ancestor, the bacterial and archaeal roots as free-living cellular organisms that independently escaped hydrothermal chimneys above marine serpentinite or alternatively from shallow pore-water environments on land, the Selabacteria root with anoxygenic photosynthesis, and the Terrabacteria root colonizing land are attractive examples that predate the geological record. Conversely, geological reasoning presents likely events for appraisal by biologists. Asteroid impacts may have produced bottlenecks by decimating life. Thermophile roots of bacteria and archaea as well as a thermophile LUCA are attractive.

FREE PDF GRATIS: Astrobiology
 

O problema cosmológico do lítio: uma das incógnitas na descrição atual do Big Bang

sexta-feira, outubro 12, 2018

7Be(n,p)7Li Reaction and the Cosmological Lithium Problem: Measurement of the Cross Section in a Wide Energy Range at n_TOF at CERN

L. Damone et al. (The n_TOF Collaboration [www.cern.ch/ntof])
Phys. Rev. Lett. 121, 042701 – Published 24 July 2018
Abstract
We report on the measurement of the 7Be(n,p)7Li cross section from thermal to approximately 325 keV neutron energy, performed in the high-flux experimental area (EAR2) of the n_TOF facility at CERN. This reaction plays a key role in the lithium yield of the big bang nucleosynthesis (BBN) for standard cosmology. The only two previous time-of-flight measurements performed on this reaction did not cover the energy window of interest for BBN, and they showed a large discrepancy between each other. The measurement was performed with a Si telescope and a high-purity sample produced by implantation of a 7Be ion beam at the ISOLDE facility at CERN. While a significantly higher cross section is found at low energy, relative to current evaluations, in the region of BBN interest, the present results are consistent with the values inferred from the time-reversal 7Li(p,n)7Be reaction, thus yielding only a relatively minor improvement on the so-called cosmological lithium problem. The relevance of these results on the near-threshold neutron production in the p+7Li reaction is also discussed.
  • Revised 9 May 2018
  • Received 16 March 2018
DOI: https://doi.org/10.1103/PhysRevLett.121.042701


Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

Published by the American Physical Society

Physics Subject Headings (PhySH) 

1. Research Areas

Big bang nucleosynthesis Nuclear reactions Nucleon induced nuclear reactions

Gravitation, Cosmology & Astrophysics Nuclear Physics
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Being Modern - The Cultural Impact of Science in the Early Twentieth Century

quinta-feira, outubro 11, 2018

Being Modern: The Cultural Impact of Science in the Early Twentieth Century

Robert Bud, Paul Greenhalgh, Frank James and Morag Shiach | October 2018

Format: 234x156mm
 
Open Access PDF
ISBN: 978-1-78735-393-0
FREE
 
Hardback
ISBN: 978-1-78735-395-4
£50.00
 
Paperback
ISBN: 978-1-78735-394-7
£30.00
 
Pages: 438
About the book

In the early decades of the twentieth century, engagement with science was commonly used as an emblem of modernity. This phenomenon is now attracting increasing attention in different historical specialties. Being Modern builds on this recent scholarly interest to explore engagement with science across culture from the end of the nineteenth century to approximately 1940.

Addressing the breadth of cultural forms in Britain and the western world from the architecture of Le Corbusier to working class British science fiction, Being Modern paints a rich picture. Seventeen distinguished contributors from a range of fields including the cultural study of science and technology, art and architecture, English culture and literature examine the issues involved. The book will be a valuable resource for students, and a spur to scholars to further examination of culture as an interconnected web of which science was a critical part, and to supersede such tired formulations as 'Science and culture'.
About the editors

Robert Bud is Research Keeper at the Science Museum in London. His award-winning publications in the history of science include studies of biotechnology and scientific instruments. Paul Greenhalgh is Director of the Sainsbury Centre at the University of East Anglia, and Professor of Art History there. He has published extensively in the history of art, design, and the decorative arts in the early modern period. Frank James is Professor of History of Science at the Royal Institution and University College London. His research formerly centred on Faraday, but now focuses on Davy. Morag Shiach is Professor of Cultural History at Queen Mary University of London. She has published extensively on the cultural history of modernism and on modernism and labour. 

Table of contents Being Modern: Introduction
Robert Bud and Morag Shiach

Section 1: Science, modernity and culture

1 Multiple modernisms in concert: the sciences, technology and culture in Vienna around 1900
Mitchell G. Ash 

2 The cinematic sound of industrial modernity: first notes
Tim Boon

3 Woolf’s atom, Eliot’s catalyst and Richardson’s waves of light: science and modernism in 1919
Morag Shiach 

4 T.S. Eliot: modernist literature, disciplines and the systematic pursuit of knowledge
Kevin Brazil

Section 2: Tensions over science 

5 Modernity and the ambivalent significance of applied science: motors, wireless, telephones and poison gas
Robert Bud 

6 ‘The springtime of science’: modernity and the future and past of science
Frank A.J.L. James 

7 ‘Come on you demented modernists, let’s hear from you’: science fans as literary critics in the 1930s
Charlotte Sleigh

Section 3: Mathematics and physics 

8 Modern by numbers: modern mathematics as a model for literary modernism
Nina Engelhardt 

9 Sculpture in the Belle Epoque: mathematics, art and apparitions in school and gallery
Lewis Pyenson 

10 Architecture, science and purity
Judi Loach

11 A Portrait of the Scientist as a Young Ham: wireless, modernity and interwar nuclear physics
Jeff Hughes 

12 Whose modernism, whose speed? Designing mobility for the future, 1880s–1945
Ruth Oldenziel 

Section 4: Life, biology and the organicist metaphor 

13 Ludwig Koch’s birdsong on wartime BBC radio: knowledge, citizenship and solace
Michael Guida 

14 ‘More Modern than the Moderns’: performing cultural evolution in the Kibbo Kift Kindred
Annebella Pollen 

15 Organicism and the modern world: from A.N. Whitehead to Wyndham Lewis and D.H. Lawrence
Craig Gordon 

16 Liquid crystal as chemical form and model of thinking in Alfred Döblin’s modernist science
Esther Leslie 

17 ‘I am attracted to the natural order of things’: Le Corbusier’s rejection of the machine
Tim Benton 

Epilogue: Science after modernity
Frank A.J.L. James and Robert Bud

Select bibliography
Index 
 
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Clusters de cromossomos ajudam a manter o genoma unido: mero acaso, fortuita necessidade ou design inteligente?

quarta-feira, outubro 10, 2018

A conserved function for pericentromeric satellite DNA

Madhav Jagannathan, Ryan Cummings, Yukiko M Yamashita

University of Michigan, United States

Research Article Mar 26, 2018 

Source/Fonte: The Scientist
 
Abstract


A universal and unquestioned characteristic of eukaryotic cells is that the genome is divided into multiple chromosomes and encapsulated in a single nucleus. However, the underlying mechanism to ensure such a configuration is unknown. Here, we provide evidence that pericentromeric satellite DNA, which is often regarded as junk, is a critical constituent of the chromosome, allowing the packaging of all chromosomes into a single nucleus. We show that the multi-AT-hook satellite DNA-binding proteins, Drosophila melanogaster D1 and mouse HMGA1, play an evolutionarily conserved role in bundling pericentromeric satellite DNA from heterologous chromosomes into ‘chromocenters’, a cytological association of pericentromeric heterochromatin. Defective chromocenter formation leads to micronuclei formation due to budding from the interphase nucleus, DNA damage and cell death. We propose that chromocenter and satellite DNA serve a fundamental role in encapsulating the full complement of the genome within a single nucleus, the universal characteristic of eukaryotic cells.  
 
eLife Digest


On Earth, life is divided into three domains. The smallest of these domains includes all the creatures, from sunflowers to yeasts to humans, that have the genetic information within their cells encased in a structure known as the nucleus. The genomes of these organisms are formed of long pieces of DNA, called chromosomes, which are packaged tightly and then unpackaged every time the cell divides. When a cell is not dividing, the chromosomes in the nucleus are loosely bundled up together.

It is well known that DNA is the blueprint for the building blocks of life, but actually most of the genetic information in a cell codes for nothing, and has unknown roles. An example of such ‘junk DNA’ is pericentrometric satellite DNA, small repetitive sequences found on all chromosomes.

However, new experiments by Jagannathan et al. show that, in the nucleus of animal cells, certain DNA binding proteins make chromosomes huddle together by attaching to multiple pericentrometric satellite DNA sequences on different chromosomes. In fact, if these proteins are removed from mice and fruit flies cells grown in the laboratory, the chromosomes cannot be clustered together. Instead, they ‘float away’, and the membranes of the nucleus get damaged, possibly buckling under the pressure of the unorganized DNA.

These events damage the genetic information, which can lead to the cell dying or forming tumors. ‘Junk DNA’ therefore appears to participate in fundamental cellular processes across species, a result that opens up several new lines of research.  
 
 
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Teoria das cordas: a energia escura é permitida mesmo?

de Sitter swampland conjecture and the Higgs potential

Frederik Denef, Arthur Hebecker, and Timm Wrase
Phys. Rev. D 98, 086004 – Published 2 October 2018
Abstract
According to a conjecture recently put forward in [1], the scalar potential V of any consistent theory of quantum gravity satisfies a bound |V|/VO(1). This forbids de Sitter solutions and supports quintessence models of cosmic acceleration. Here, we point out that in the simplest models incorporating the standard model in addition to quintessence, with the two sectors decoupled as suggested by observations, the proposed bound is violated by 50 orders of magnitude. However, a very specific coupling between quintessence and just the Higgs sector may still be allowed and consistent with the conjecture.
  • Received 7 August 2018
DOI: https://doi.org/10.1103/PhysRevD.98.086004

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP3.

Published by the American Physical Society

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Existe um paradigma darwinista? Por uma ontologia histórica da teoria da evolução

terça-feira, outubro 09, 2018

Existe-t-il un paradigme darwinien? Pour une ontologie historique de la théorie de l’évolution
 
Nicola Bertoldi Université de Paris 1 - Panthéon Sorbonne
DOI: https://doi.org/10.20416/lsrsps.v5i1.8
 
Mots-clés: histoire et philosophie de la biologie, théorie de l’évolution, paradigme, Thomas Kuhn, ontologie historique 

Source/Fonte: New Scientist


Résumé

La théorie de Darwin est considérée par de nombreux historiens comme une véritable révolution scientifique, raison pour laquelle l’objectif de cet article est précisément de rendre compte des caractères révolutionnaires de cette théorie, dans le cadre d’une conception des révolutions scientifiques empruntée à l’œuvre de Thomas Kuhn. Cela implique, notamment, la définition d’un « paradigme darwinien », à la fois comme matrice disciplinaire et comme solution exemplaire à un problème donné. Dans un tel but, nous définirons la structure et le contenu de la théorie de Darwin, afin de mettre au jour la problématique qui pourrait être à la base d’un « paradigme darwinien », c’est-à-dire le problème de la complexité adaptative du vivant. Nous identifierons ensuite ce qui distinguerait ce paradigme des autres, si bien que le problème de la complexité ne saurait être posé et résolu que dans son cadre. Pour ce faire, nous nous concentrerons sur deux dichotomies : d’une part, celle entre fonctionnalisme et formalisme, d’autre part, celle entre naturalisme et idéalisme. En conclusion, nous mettrons au jour les limites de l’épistémologie kuhnienne pour l’analyse de la théorie de l’évolution, ce qui nous amènera à equisser les contours d’une approche alternative, que nous appellerons « ontologie historique ».
 
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Darwin, as teorias bem estabelecidas de padrões na evolução podem estar erradas

segunda-feira, outubro 01, 2018

History is written by the victors: The effect of the push of the past on the fossil record

Graham E. Budd Richard P. Mann

First published: 26 September 2018 https://doi.org/10.1111/evo.13593


Abstract

Survivorship biases can generate remarkable apparent rate heterogeneities through time in otherwise homogeneous birth‐death models of phylogenies. They are a potential explanation for many striking patterns seen in the fossil record and molecular phylogenies. One such bias is the “push of the past”: clades that survived a substantial length of time are likely to have experienced a high rate of early diversification. This creates the illusion of a secular rate slow‐down through time that is, rather, a reversion to the mean. An extra effect increasing early rates of lineage generation is also seen in large clades. These biases are important but relatively neglected influences on many aspects of diversification patterns in the fossil record and elsewhere, such as diversification spikes after mass extinctions and at the origins of clades; they also influence rates of fossilization, changes in rates of phenotypic evolution and even molecular clocks. These inevitable features of surviving and/or large clades should thus not be generalized to the diversification process as a whole without additional study of small and extinct clades, and raise questions about many of the traditional explanations of the patterns seen in the fossil record.

Subscription or payment needed/Requer assinatura ou pagamento. Evolution

Desvendando o mecanismo que protege o DNA replicado da degradação: mero acaso, fortuita necessidade ou design inteligente?

domingo, setembro 30, 2018

AND-1 fork protection function prevents fork resection and is essential for proliferation 
 

Takuya Abe, Ryotaro Kawasumi, Michele Giannattasio, Sabrina Dusi, Yui Yoshimoto, Keiji Miyata, Koyuki Umemura, Kouji Hirota & Dana Branzei

Nature Communications volume 9, Article number: 3091 (2018)

Abstract

AND-1/Ctf4 bridges the CMG helicase and DNA polymerase alpha, facilitating replication. Using an inducible degron system in avian cells, we find that AND-1 depletion is incompatible with proliferation, owing to cells accumulating in G2 with activated DNA damage checkpoint. Replication without AND-1 causes fork speed slow-down and accumulation of long single-stranded DNA (ssDNA) gaps at the replication fork junction, with these regions being converted to DNA double strand breaks (DSBs) in G2. Strikingly, resected forks and DNA damage accumulation in G2, but not fork slow-down, are reverted by treatment with mirin, an MRE11 nuclease inhibitor. Domain analysis of AND-1 further revealed that the HMG box is important for fast replication but not for proliferation, whereas conversely, the WD40 domain prevents fork resection and subsequent DSB-associated lethality. Thus, our findings uncover a fork protection function of AND-1/Ctf4 manifested via the WD40 domain that is essential for proliferation and averts genome instability.

Author information

Author notes

These authors contributed equally: Takuya Abe, Ryotaro Kawasumi.

Affiliations

IFOM, the FIRC Institute of Molecular Oncology, Via Adamello 16, 20139, Milan, Italy

Takuya Abe, Ryotaro Kawasumi, Michele Giannattasio, Sabrina Dusi & Dana Branzei

Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minamiosawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
Takuya Abe, Yui Yoshimoto, Keiji Miyata, Koyuki Umemura & Kouji Hirota

Dipartimento di Oncologia ed Emato-Oncologia, Università degli Studi di Milano, Milan, 20122, Italy
Michele Giannattasio

Istituto di Genetica Molecolare, Consiglio Nazionale delle Ricerche (IGM-CNR), Via Abbiategrasso 207, 27100, Pavia, Italy
Dana Branzei

Contributions

T.A., R.K., and D.B. designed the research; T.A. and R.K. performed the experiments; M.G. and S.D. performed TEM sample acquisition and analysis; Y.Y., K.M., K.U., and K.H. contributed to experiments on molecular combing and pulse field gel electrophoresis; T.A., R.K., and D.B analyzed the data; T.A. and R.K. made the figures; D.B. wrote the paper and all authors contributed suggestions. 

Competing interests

The authors declare no competing interests.
Corresponding author

Correspondence to Dana Branzei.

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Darwin, a evolução pré-darwinista é plausível? As evidências dizem NÃO!

sexta-feira, setembro 21, 2018

Is pre-Darwinian evolution plausible?

Marc TesseraEmail authorView ORCID ID profile
Biology Direct201813:18

https://doi.org/10.1186/s13062-018-0216-7

© The Author(s). 2018
Received: 29 December 2017 Accepted: 15 June 2018 Published: 21 September 2018 


 Abstract

Background

This essay highlights critical aspects of the plausibility of pre-Darwinian evolution. It is based on a critical review of some better-known open, far-from-equilibrium system-based scenarios supposed to explain processes that took place before Darwinian evolution had emerged and that resulted in the origin of the first systems capable of Darwinian evolution. The researchers’ responses to eight crucial questions are reviewed. The majority of the researchers claim that there would have been an evolutionary continuity between chemistry and “biology”. A key question is how did this evolution begin before Darwinian evolution had begun? In other words the question is whether pre-Darwinian evolution is plausible.

Results

Strengths and weaknesses of the reviewed scenarios are presented. They are distinguished between metabolism-first, replicator-first and combined metabolism-replicator models. The metabolism-first scenarios show major issues, the worst concerns heredity and chirality. Although the replicator-first scenarios answer the heredity question they have their own problems, notably chirality. Among the reviewed combined metabolism-replicator models, one shows the fewest issues. In particular, it seems to answer the chiral question, and eventually implies Darwinian evolution from the very beginning. Its main hypothesis needs to be validated with experimental data.

Conclusion

From this critical review it is that the concept of “pre-Darwinian evolution” appears questionable, in particular because it is unlikely if not impossible that any evolution in complexity over time may work without multiplication and heritability allowing the emergence of genetically and ecologically diverse lineages on which natural selection may operate. Only Darwinian evolution could have led to such an evolution. Thus, Pre-Darwinian evolution is not plausible according to the author. Surely, the answer to the question posed in the title is a prerequisite to the understanding of the origin of Darwinian evolution.

Reviewers

This article was reviewed by Purificacion Lopez-Garcia, Anthony Poole, Doron Lancet, and Thomas Dandekar. 

Keywords

Metabolism-first Replicator-first Combined metabolism-replicator scenarios
Pre-Darwinian evolution Prebiotic evolution Darwinian evolution Origin of life
Origin of Darwinian evolution
 
FREE PDF GRATIS: Biology Direct

Darwin, explica aí: moléculas de colesterol de 558 milhões de anos preservadas intactas?

Ancient steroids establish the Ediacaran fossil Dickinsonia as one of the earliest animals

Ilya Bobrovskiy1,*, Janet M. Hope1, Andrey Ivantsov2, Benjamin J. Nettersheim3, Christian Hallmann3,4, Jochen J. Brocks1,*
 
1Research School of Earth Sciences, Australian National University, Canberra ACT 2601, Australia.
 
2Borissiak Paleontological Institute, Russian Academy of Sciences, Moscow 117997, Russia.
 
3Max Planck Institute for Biogeochemistry, Jena 07745, Germany.
 
4MARUM–Center for Marine Environmental Sciences, University of Bremen, Bremen 28359, Germany.
 
*Corresponding author. Email: ilya.bobrovskiy@anu.edu.au (I.B.); jochen.brocks@anu.edu.au (J.J.B.)

 Science 21 Sep 2018: Vol. 361, Issue 6408, pp. 1246-1249
DOI: 10.1126/science.aat7228
 
Source/Fonte: The Australian National University (ANU)
 
Confirming the identity of early animals

The first complex organisms emerged during the Ediacaran period, around 600 million years ago. The taxonomic affiliation of many of these organisms has been difficult to discern. Fossils of Dickinsonia, bilaterally symmetrical oval organisms, have been particularly difficult to classify. Bobrovskiy et al. conducted an analysis using lipid biomarkers obtained from Dickinsonia fossils and found that the fossils contained almost exclusively cholesteroids, a marker found only in animals (see the Perspective by Summons and Erwin). Thus, Dickinsonia were basal animals. This supports the idea that the Ediacaran biota may have been a precursor to the explosion of animal forms later observed in the Cambrian, about 500 million years ago.

Science, this issue p. 1246; see also p. 1198

Abstract

The enigmatic Ediacara biota (571 million to 541 million years ago) represents the first macroscopic complex organisms in the geological record and may hold the key to our understanding of the origin of animals. Ediacaran macrofossils are as “strange as life on another planet” and have evaded taxonomic classification, with interpretations ranging from marine animals or giant single-celled protists to terrestrial lichens. Here, we show that lipid biomarkers extracted from organically preserved Ediacaran macrofossils unambiguously clarify their phylogeny. Dickinsonia and its relatives solely produced cholesteroids, a hallmark of animals. Our results make these iconic members of the Ediacara biota the oldest confirmed macroscopic animals in the rock record, indicating that the appearance of the Ediacara biota was indeed a prelude to the Cambrian explosion of animal life. 
 
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Novo livro de Michael Behe sobre o declínio de Darwin: a nova ciência do DNA desafia a teoria da evolução

quarta-feira, setembro 19, 2018

Darwin Devolves: The New Science About DNA that Challenges Evolution Hardcover – February 26, 2019
by Michael J. Behe (Author)

The scientist who has been dubbed the “Father of Intelligent Design” and author of the groundbreaking book Darwin’s Black Box contends that recent scientific discoveries further disprove Darwinism and strengthen the case for an intelligent creator.

In his controversial bestseller Darwin’s Black Box, biochemist Michael Behe challenged Darwin’s theory of evolution, arguing that science itself has proven that intelligent design is a better explanation for the origin of life. In Darwin Devolves, Behe advances his argument, presenting new research that offers a startling reconsideration of how Darwin’s mechanism works, weakening the theory’s validity even more.

A system of natural selection acting on random mutation, evolution can help make something look and act differently. But evolution never creates something organically. Behe contends that Darwinism actually works by a process of devolution—damaging cells in DNA in order to create something new at the lowest biological levels. This is important, he makes clear, because it shows the Darwinian process cannot explain the creation of life itself. “A process that so easily tears down sophisticated machinery is not one which will build complex, functional systems,” he writes.

In addition to disputing the methodology of Darwinism and how it conflicts with the concept of creation, Behe reveals that what makes Intelligent Design unique—and right—is that it acknowledges causation. Evolution proposes that organisms living today are descended with modification from organisms that lived in the distant past. But Intelligent Design goes a step further asking, what caused such astounding changes to take place? What is the reason or mechanism for evolution? For Behe, this is what makes Intelligent Design so important.
 
 
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Darwin, as mutações genéticas frustram os esforços científicos de prever plenamente o nosso futuro

segunda-feira, setembro 17, 2018

The complex underpinnings of genetic background effects

Martin N. Mullis, Takeshi Matsui, Rachel Schell, Ryan Foree & Ian M. Ehrenreich 

Nature Communications volume 9, Article number: 3548 (2018) 

Article | OPEN | Published: 17 September 2018

Source/Fonte: Evolution Berkeley

Abstract

Genetic interactions between mutations and standing polymorphisms can cause mutations to show distinct phenotypic effects in different individuals. To characterize the genetic architecture of these so-called background effects, we genotype 1411 wild-type and mutant yeast cross progeny and measure their growth in 10 environments. Using these data, we map 1086 interactions between segregating loci and 7 different gene knockouts. Each knockout exhibits between 73 and 543 interactions, with 89% of all interactions involving higher-order epistasis between a knockout and multiple loci. Identified loci interact with as few as one knockout and as many as all seven knockouts. In mutants, loci interacting with fewer and more knockouts tend to show enhanced and reduced phenotypic effects, respectively. Cross–environment analysis reveals that most interactions between the knockouts and segregating loci also involve the environment. These results illustrate the complicated interactions between mutations, standing polymorphisms, and the environment that cause background effects.

Acknowledgements

We thank Norm Arnheim, Mark Chaisson, Matt Dean, Sasha Levy, David Pfennig, and Kevin Roy for comments on a draft of this manuscript. We also thank Alessandro Coradini, Jonathan Lee, and Fabian Seidl for input during the execution of this project and writing of this paper. The research described in this manuscript was supported by grant R01GM110255 from the National Institutes of Health, as well as a Computational and Evolutionary Molecular Biology fellowship from the Alfred P. Sloan Foundation to I.M.E. and a Research Enhancement Fellowship from the USC Graduate School to M.N.M. Many of the analyses described in this paper were performed on the USC High-Performance Computing cluster.

Author information

Author notes

These authors contributed equally: Martin N. Mullis, Takeshi Matsui, Rachel Schell.

Affiliations

Molecular and Computational Biology Section, Department of Biological Sciences, University of Southern California, Los Angeles, CA, 90089-2910, USA

Martin N. Mullis, Takeshi Matsui, Rachel Schell, Ryan Foree & Ian M. Ehrenreich

Contributions

M.N.M., T.M., R.S. and I.M.E. conceptualized this project. M.N.M., T.M., R.S. and R.F. performed experiments. M.N.M., T.M. and I.M.E. analyzed data. M.N.M., T.M., R.S. and I.M.E. wrote the paper.

Competing interests

The authors declare no competing interests.

Corresponding authors

Correspondence to Martin N. Mullis or Takeshi Matsui or Ian M. Ehrenreich.

Faleceu o geneticista Luigi Luca Cavalli-Sforza (1922-2018): um pássaro na gaiola dourada

quinta-feira, setembro 13, 2018

L.L. Cavalli-Sforza: A bird in a gilded cage

Open Behavioral Genetics, 2014, ISSN: 2446-3876

Peter Frost


Abstract 

Luigi Luca Cavalli-Sforza is a complex figure. On the one hand, he has publicly backed those who assert that human races do not exist. On the other hand, by aggregating large volumes of genetic data, he has proven the existence of large continental races, as well as smaller regional and micro ones. By developing the theory of gene-culture co-evolution, he has also shown that humans did not stop evolving genetically when they began to evolve culturally. In fact, the two processes have fed into each other, with humans having to adapt not only to the natural portion of their environment (climate, vegetation, wildlife, etc.) but also to the portion they themselves have created (mode of subsistence, behavioral norms, gender roles, class structure, belief system, etc.). This has led some to see a double game at work. While bowing to the mainstream taboos, Cavalli-Sforza has quietly amassed evidence that human races not only exist but also differ in ways that are more than skin deep. In time, his weighty tomes will speak louder than his official statements on race. This may indeed be how he sees himself, and it might explain certain contradictions between his public persona and his academic self. Oh, those naïve antiracists, if only they knew how they’re being outfoxed! Time will tell who is outfoxing whom. To date, the results speak for themselves. When in 1994 Cavalli-Sforza published The History and Geography of Human Genes, academics and nonacademics alike were talking more openly about race, as seen by the publication the same year of The Bell Curve and by the willingness of previously silent anthropologists, like Vincent Sarich, to step forward and speak out. That interval of glasnost soon ended, in no small part because of Cavalli-Sforza’s apparent conversion, as attested in his book, to the view that human races do not exist in any meaningful sense. Why did he convert? And did he really? I doubt there was any conversion. His change of heart was too rapid, and it happened while the zeitgeist was moving in the other direction. Perhaps he saw a chance to gain acceptance for his new tome. Or perhaps he received a letter one day, detailing his wartime record, the people he worked with, and the testing on human subjects … Cavalli-Sforza had to remake his life when the war ended. He never denied the nature of his wartime research (the time it takes for anthrax to kill its host) but tried to create the impression that he was doing pure research with no military implications. Yet this was Berlin, in 1943-1944. There was no money for pure research. Was he motivated by opportunism, the chance to gain experience in his field of study? Or did he feel loyalty to the Axis cause? It is difficult to say, and perhaps it doesn’t matter. It is enough to say that he later saw his wartime research as a stain on his record and tried to minimize it as much as possible. He was thus vulnerable to blackmail, or rather to his chronic fear of blackmail. We will probably never know the full story. One thing is sure. If Cavalli-Sforza is playing a double game, he has been playing it far too long. Such a strategy is excusable for an academic who is young, untenured, poorly known, and far from retirement, but these excuses hardly apply to a professor emeritus like Cavalli-Sforza. The time is overdue to speak frankly and, if need be, pay the price. Anyway, what else can he do now with his vast reserves of public esteem? Take it with him to the next world?

FREE PDF GRATIS: Open Behavioral Genetics

Darwin, não é mero acaso, nem fortuita necessidade, mas informação!

terça-feira, setembro 11, 2018

EMBO Reports

Will biologists become computer scientists?

A truly interdisciplinary effort by computer scientists and biologists to understand how cells process information may yield new insights for both fields

Anne Condon Hélène Kirchner Damien Larivière Wallace Marshall Vincent Noireaux Tsvi Tlusty Eric Fourmentin

First published: 30 July 2018 https://doi.org/10.15252/embr.201846628


Abstract

The idea that living systems could be understood and described as information‐processing systems has been around even before the first computers were built. From Alan Turing's considerable paper in 1936 to Erwin Schrödinger's work in 1944 and John von Neumann's work in 1948 [1], many scientists pondered about information storage and the possible existence of a logical processor within living cells. The discovery of the double‐helical structure of DNA in 1953 provided the material basis for these intuitions as it finally revealed how cells store inheritable information in a “digital” format. The recent success of genome transplantation experiments into recipient host cells [2]—akin to transferring software to another computer—further strengthened the hypothesis that living cells can be regarded as Turing Machines, as was suggested by Sydney Brenner [3] (see Sidebar 1 for a glossary and Sidebar 2 for further readings).

… many scientists pondered about information storage and the possible existence of a logical processor within living cells.

François Jacob and Jacques Monod were among the first biologists to understand gene expression as an algorithm.

In light of these and other experimental results that would support the hypothesis that some parts of living systems could be understood as information‐processing machines, the Fourmentin‐Guilbert Scientific Foundation invited international scholars from the life sciences, computer sciences and physical sciences (see Sidebar 3) to the I2CELL (from Information to Cells) seminar in February 2018 near Oxford, UK, to discuss and identify new research areas. Over 3 days, they debated on a broad range of subjects from computation, information handling, algorithms, robotics and viruses (of the digital and biological varieties) to explore analogies between cells and computers that could inspire new research, while keeping a critical approach to the benefits of similarities. …

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NOTA DESTE BLOGGER: 

Qual teoria que tem a INFORMAÇÃO em seu arcabouço teórico? A atual teoria geral da evolução de Darwin - a Síntese Evolutiva Ampliada/Estendida lançada em agosto de 2015? Lidou apenas en passant. A única teoria que tem a INFORMAÇÃO no seu arcabouço teórico é a Teoria do Design Inteligente: informação complexa especificada.