genome transplantation

Les gènes ne jouent qu’un rôle mineur, disait l’autre

Science Daily — Researchers at the J. Institute (JCVI) have announced the results of work on genome transplantation methods allowing them to transform one type of bacteria into another type dictated by the transplanted chromosome. The work, published online in the journal Science, by JCVI’s , Ph.D. and colleagues, outlines the methods and techniques used to change one bacterial species, Mycoplasma capricolum into another, Mycoplasma mycoides Large Colony (LC), by replacing one organism’s genome with the other one’s genome.

Ce n’est pas une étape mineur que nous avons là, mais bel et bien la technique qui permettra à un génome synthétique d’être inséré dans une cellule qui lui servira de starter. C’est bien plus facile que d’être obligé de mettre en place l’enveloppe à partir de ses constituants.

Genome Transplantation in Bacteria: Changing One Species to Another

Carole Lartigue, John I. Glass, Nina Alperovich, Rembert Pieper, Prashanth P. Parmar, Clyde A., Hutchison III, Hamilton O. Smith, J. Craig Venter / 28 June 2007 / Page 1 / 10.1126/1144622

As a step toward propagation of , we completely replaced the genome of a bacterial cell with one from another species by transplanting a whole genome as naked DNA. Intact genomic DNA from Mycoplasma mycoides large colony (LC), virtually free of protein, was transplanted into Mycoplasma capricolum cells by polyethylene glycol-mediated transformation. Cells selected for tetracycline resistance, carried by the M. mycoides LC chromosome, contain the complete donor genome and are free of detectable recipient genomic sequences. These cells that result from are phenotypically identical to the M. mycoides LC donor strain as judged by several criteria.

Evolution of cooperation in a finite homogeneous graph

Ca par exemple ! Mignon tout plein. M’est avis que c’est de la bonne

Peter D. Taylor, Troy Day& Geoff Wild

Vol 447 | 24 May 2007 | doi:10.1038/nature05784

Recent theoretical studies of selection in finite structured populations have worked with one of two measures of selective advantage of an allele: fixation probability and inclusive fitness. Each approach has its own analytical strengths, but given certain assumptions they provide equivalent results1. In most instances the structure of the population can be specified by a network of nodes connected by edges (that is, a graph), and much of the work here has focused on a continuous-time model of evolution, first described by Moran, P. A. P. (Statistical Processes of Evolutionary Theory (Oxford, Clarendon, 1962)). Working in this context, we provide an inclusive fitness analysis to derive a surprisingly simple analytical condition for the selective advantage of a cooperative allele in any graph for which the structure satisfies a general symmetry condition (‘bi-transitivity’). Our results hold for a broad class of population structures, including most of those analysed previously, as well as some for which a direct calculation of fixation probability has appeared intractable. Notably, under some forms of population regulation, the ability of a cooperative allele to invade is seen to be independent of the nature of population structure (and in particular of how game partnerships are specified) and is identical to that for an unstructured population. For other types of population regulation our results reveal that cooperation can invade if players choose partners along relatively ‘high-weight’ edges.

Ignorance is no crime

Scientific American, July 2007
p 890 :

Dawkins: […] Ignorance is no crime. To call somebody ignorant is no insult. All of us are ignorant of most of what there is to know. I am completely ignorant of baseball, and I dare say that you are as completely ignorant of cricket. If I tell somebody who believes the world is 6,000 years old that he is ignorant, I am paying him the compliment of assuming that he is not stupid, insane or wicked.

Krauss: I have to say that I agree completely with you about this. To me, ignorance is often the problem, and, happily, ignorance is most easily addressed. It is not pejorative to suggest that someone is ignorant if they misunderstand scientific issues.

homeotic control over Petunia hybrida and Antirrhinum majus floral organ identity

Même les plantes dites-donc 🙂

A conserved microRNA module exerts homeotic control over Petunia hybrida and Antirrhinum majus floral organ identity

Maria Cartolano, Rosa Castillo, Nadia Efremova, Markus Kuckenberg, Jan Zethof, Tom Gerats, Zsuzsanna Schwarz-Sommer & Michiel Vandenbussche


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evo-devo by Sean Carroll

Sean B. Carroll discusses the science of evolution and the field of evo-devo.

Related article: From a Few Genes, Life’s Myriad Shapes, by Carol Kaesuk Yoon

Since its humble beginnings as a single cell, life has evolved into a spectacular array of shapes and sizes, from tiny fleas to towering Tyrannosaurus rex, from slow-soaring vultures to fast-swimming swordfish, and from modest ferns to alluring orchids. But just how such diversity of form could arise out of evolution’s mess of random genetic mutations — how a functional wing could sprout where none had grown before, or how flowers could blossom in what had been a flowerless world — has remained one of the most fascinating and intractable questions in evolutionary biology.

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Le dernier post de PZ Myers (23/06/2007) tombe à pic après la lecture de Setting the Tempo in Development.
Merde, si les gradients de morphogènes sont présents dans l’oeuf déjà et qu’ils sont les produits d’expression de gènes il se peut que Fleury ait tort ! 🙂 Est-ce possible ? Probablement oui.

Autoinhibition with Transcriptional Delay

Autoinhibition with Transcriptional Delay: A Simple Mechanism for the Zebrafish Somitogenesis Oscillator

Current Biology, Vol. 13, 1398–1408, August 19, 2003

Julian Lewis

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