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Thursday, October 23, 2008
Happy Birthday Universe!
Bishop James Ussher (1581 - 1656) was Archbishop of Armagh and Primate of All Ireland. He calculated that the universe was created on this day in 4004 BC, or more correctly the night before this day.
In addition to astute Biblical scholarship, the calculation required a knowledge of ancient history. Ussher's estimates of ancient dates were pretty good for his time.
We now know that his calculation was flawed because the Bible is completely wrong about creation but it is unfair to make fun of Ussher based on what we learned several centuries later.
Happy Birthday Universe.
Wednesday, October 22, 2008
Nobel Laureate: Hermann Muller
The Nobel Prize in Physiology or Medicine 1946.
"for the discovery of the production of mutations by means of X-ray irradiation"
Hermann Joseph Muller (1890 - 1967) won the Noble Prize for showing that X-rays could induce mutations in Drosophila melanogaster. He was able to isolate and map specific mutations caused by X-rays showing that these were stable genetic changes.
For a brief description of the technique, see Hermann Muller Invented Balancer Chromosome.
The significance of Muller's work is described in the presentation speech on the Nobel rize website.
THEME:
Nobel Laureates
It was known, already at the turn of the century, that apparently sudden changes may appear spontaneously in the hereditary mass, which result in changes in the characteristics of the organism. We now know that these changes may be of different types, and among them occur also disturbances in individual genes. These are very rare, however. Even in such a convenient experimental object as the banana fly, introduced by Morgan, where the generations succeed each other rapidly, and thousands of flies can be examined, it is only seldom that mutations are observed. Muller grappled with the task of trying to change the frequency of mutations. He first created procedures, technically extremely elegant, by which the mutation frequency could be measured exactly. When this task - which took several years - had been completed, the effect of different agents on the frequency of mutations was investigated, and the discovery for which the Nobel Prize is now awarded was made, viz. that irradiation with X-rays evokes large numbers of mutations. Experiments could be arranged, for instance, so that nearly 100 per cent of the offspring of irradiated flies showed mutations. Thus a possibility had been created for the first time of influencing the hereditary mass itself artificially.
This discovery aroused a great sensation already when it was first published in 1927 and rapidly led to a great deal of work of different kinds and in the most varied directions. The mechanism of the effect of rays was studied by many research workers, with Muller at their head. Greatly simplified X-ray irradiation, as also ionizing irradiation, could be likened in general to a shower of infinitely small (even compared with the individual cell) but highly explosive grenades, which explode at different spots within the irradiated organism. The explosion itself (or the fragments it throws up) tears the structure of the cell to pieces or disturbs its arrangement. If such an explosion happens to take place in or close to a gene, its structure, and therewith also its effect on the organism, may be changed.
Muller's discovery of the induction of mutations by means of rays has been of tremendous importance for genetics and biology in general.
Tuesday, October 21, 2008
The Christian Man's Evolution
A posting on the Scientific American website describes the view of Francisco J. Ayala, a man who was ordained as a Dominican priest who is also an excellent scientist [The Christian Man's Evolution: How Darwinism and Faith Can Coexist .
Here's an excerpt ...
Ayala graduated in physics at the University of Madrid, then worked in a geneticist’s lab while studying theology at the Pontifical Faculty of San Esteban in Salamanca, Spain. By his ordination in 1960 he had already decided to pursue science instead of a ministerial role. At the monastery Darwinism had never been perceived as an enemy of Christian faith. So a year later, when Ayala moved to New York City to pursue a doctorate in genetics, the prevailing U.S. view of a natural hostility between evolution and religion was a shock.I've already commented on the National Academys' sellout to political correctness and on the fact that Ayala was Chair of the committee [Richard Dawkins on the Michael Reiss Affair] [National Academies: Science, Evolution and Creationism]. The fallacy here is something called The Doctrine of Joint Belief.
Ever since, Ayala has attempted to address religious skepticism about Darwin’s theory. At first, he recalls, his scientific colleagues were wary and took the position that researchers should not engage in religious discussions. By 1981, when the Arkansas legislature voted to give creationism equal time in schools, the mood began to change. The National Academy of Sciences prepared an amicus curiae brief for a Supreme Court case on the Louisiana “Creation Act” and asked Ayala to lead the effort. The booklet became the 1984 Science and Creationism: A View from the National Academy of Sciences.
For the second edition in 1999 Ayala presented the idea of incorporating the words of some theologians but recalls, “I was almost eaten alive.” In the third edition, published this year, one section features statements by four religious denominations and three scientists on the compatibility of evolution with religious beliefs.
That's not what I want to comment on today. I want to draw your attention to the use of "Darwinism" in the title of the article and to "Darwin's theory" in the body of the article. The author, Sally Lehrman1, should know better. If she's going to write for Scientific American then she better learn that the correct terms are "evolution" and "evolutionary theory." The editors of Scientific America should know better, but then what can you expect from a magazine that has fallen so far from its heydays in the 60s and 70s?
1. "Sally Lehrman teaches journalism in the public interest at Santa Clara University."
Hermann Muller Invented the Balancer Chromosome
Since writing about Balancer Chromosomes, I've gotten several email messages pointing out things I missed. Thanks to everyone who responded. It's what makes this blog worthwhile.
Quite a few readers pointed out that balancer chromosomes were invented a very long time ago by Hermann Muller. Muller won the Nobel Prize in 1946 for discovering mutagenesis by X-rays.
Dale Hoyt, a fly geneticist, sent me a description of Muller's experiment and he has given me permission to post it.
Quite a few readers pointed out that balancer chromosomes were invented a very long time ago by Hermann Muller. Muller won the Nobel Prize in 1946 for discovering mutagenesis by X-rays.
Dale Hoyt, a fly geneticist, sent me a description of Muller's experiment and he has given me permission to post it.
The first Nobel laureate who used balancers in his work was Hermann J. Muller. He used a strain of D. melanogaster that was heterozygous for an X-chromosome inversion. This suppresses crossing over between the normal X and the X carrying the inversion during meiosis. A single crossover within the inverted segment will generate a "bridge" at meiosis I, causing the non-crossover chromatid to preferentially segregate to the future ovum. In Muller's work the inverted X was marked with the dominant eye shape mutation, Bar, and carried a recessive lethal allele.1 A female heterozygous for the marked inverted chromosome and a "wild type" chromosome will produce only 1/2 the normal number of male progeny and they will all be wild type. This is because 1/2 the males die because they receive the Bar chromosome and are hemizygous for the lethal. The inversion heterozygosity prevents recombination between the Bar locus and the lethal locus. Muller used this stock, called "ClB", to show that X-irradiation increased the frequency of mutation to lethal genes on the X-chromosome. Irradiated male flies were individually mated to the ClB females. Their Bar-eyed female offspring (heterozygous for the inversion and the irradiated X-chromosome) were mated to their brothers. If no males were produced from this cross then the irradiated male transmitted an X chromosome with a lethal mutation. It was easy to score the crosses—just look at the bottle and if there were no males then Muller knew that he had a radiation induced lethal.
1. l(1)C, associated with the left breakpoint of the inversions. Presumably the break disrupts a gene required for viability. The gene must be known by now.
[Photo Credit: WIRED]
Labels:
Genes
Monday, October 20, 2008
The Lactose Paradox
The lac operon in E. coli consists of three genes (lacZ, lacY and lacA) transcribed from a single promoter. The lacZ gene encodes the enzyme β-galactosidase, an enzyme that cleaves β-galactosides. Lactose is a typical β-galactoside and the enzyme cleaves the disaccharide converting it to separate molecules of glucose and galactose. These monosacharides can enter into the metabolic pool of the cell where they can serve as the sole source of carbon.Transcription of the lac operon begins when RNA polymerase binds to the Plac promoter. The long polycistronic mRNA (wavy line) is translated to produce the three proteins.
LacY encodes a famous transporter called lactose permease. It is responsible for importing βgalactosides. The lacA gene encodes a transacetylase that is responsible for detoxifying the cell when it takes up poisonous β-galactosides.
[from The Lac Operon]
In the absence of lactose, transcription of the lac operon is blocked by a repressor protein that binds to two sites (O1 and O2) preventing RNA polymerase from transcribing the operon [Repression of the lac Operon].
When the bacteria encounter lactose, transcription of the lac operon is induced but since the operon has a weak promoter not much protein will be produced as long as glucose is present. Glucose is always the preferred carbon source. In the absence of both glucose and lactose the operon is maximally induced by the activator CRP-cAMP.
Lactose induces transcription by causing a change in the structure of the repressor so that it no longer binds to DNA. When that happens, RNA polymerase can transcribe the operon.
Here's the paradox. Lactose can't enter the cell unless it's transported across the membrane by the permease and the permease can only be made if the lac operon is transcribed. Furthermore, lactose itself doesn't bind to the lac repressor causing it to detatch from its binding sites. Instead, the actual inducer is allolactose, a modified form of lactose that can only be synthesized inside the cell by the enzyme β-galactosidase. β-galactosidase can only be synthesized if the operon is transcribed.
This is known as the "lactose paradox." It seems you can't induce the operon unless there's allolactose present and the only way to get allolactose is to take up lactose via the permease and convert it to allolactose via β-galactosidase.
The "paradox" was explained many decades ago when it was discovered that the lac operon is transcribed at least once whenever the lac repressor dissociates from its binding sites. The lac repressor is a highly specific DNA binding protein that binds very tightly to O1 and O2. But no protein can bind forever. When it dissociates, an mRNA is made and some permease and some β-galactosidase is synthesized. The repressor quickly re-binds and transcription is blocked.
The effect of this "escape" synthesis is that there will always be a few molecules of permease and a few molecules of β-galactosidase inside the cell. When the cell encounters lactose in the medium enough can be taken up and converted to allolactose to induce the operon.
A paper published in this week's issue of Science looked at the number of permease molecules that had to be present in order to induce transcription of the lac operon and discovered that there had to be about 300 molecules present. Some bacterial cells had fewer molecules of permease, by chance, so the repressor remained bound to DNA. Other cells had more than 300 molecules of permease so transcription of the operon was induced and many more molecules of permease were synthesized (Choi et al. 2008).
This is an interesting result but it might not be worth blogging about except for one thing. Our friendly IDiot DaveScot decided to use this paper to prove that evolution is wrong!! You can read all about it on Panda's Thumb: Scientific Vacuity of ID: Lactose Digestion in E. coli.
There's one more wrinkle to this story. Lactose is probably not the main substrate for β-galactosidase and it's quite likely that a typical E. coli cell never sees lactose. When they're not inside a human gut, E. coli cells won't ever encounter lactose. Even when they're living inside a friendly human, it will most often be an adult and throughout most of evolutionary history human adults did not consume milk. E. coli usually does not make up a significant proportion of the bacteria in nursing infants.
So, what is the real product of β-galactosidase and the real inducer of the lac operon? It's likely to be various other β-galactosides such as β-galactosyl glycerol. These are common breakdown products of plant membranes. They are transported efficiently by the permease but they can also be transported by a galactose permease that is always present in the bacteria membrane. Furthermore, β-galactosyl glycerol is a direct inducer of the lac operon. It binds directly to lac repressor so there's no need to convert it to something else (Egel, 1988).
While there may be a "lactose paradox" there is no "β-galactosyl glycerol paradox."
Choi, P.J., Cai, L., Frieda, K., and Xie, X.S. (2008) A stochastic single-molecule event triggers phenotype switching of a bacterial cell. Science 322:442-6. [DOI: 10.1126/science.1161427]
Egel, R. (1988) The "lac" operon: an irrelevant paradox? Trends in Genetics 4:31.
Labels:
Biochemistry
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Genes
Adoptees use DNA to find surname
This is an example of a real ethical problem. You might be surprised to learn that there aren't all that many "real" ethical problems. Most of the ones that are proposed are pseudo-ethical problems.
In this case, an article from BBC News describe how Adoptees use DNA to find surname.
Male adoptees are using consumer DNA tests to predict the surnames carried by their biological fathers, the BBC has learned.Why is this an ethical problem? Because it (potentially) involves a conflict between the wishes of two individuals. The adoptee wants to know who his biological parents are and the biological parents may wish to remain unknown.
They are using the fact that men who share a surname sometimes have genetic likenesses too.
By searching DNA databases for other males with genetic markers matching their own, adoptees can check if these men also share a last name.
This can provide the likely surname of an adoptee's biological father.
As far as I'm concerned, the wishes of the biological parents have to be respected but with the widespread use of commercial DNA testing services, this wish can be circumvented by a determined adoptee.
Incidentally, these tests are also going to reveal who isn't your father, and that's also a problem.
There are many blogs acting as cheerleaders for the new commercial DNA testing services. One of them, The Genetic Genealogist seems to think that finding out who your father is, or isn't, is a good thing. That blog even points to a commercial company runnnig a program for adoptees with a success rate of more than 30% [More On Revealing Surnames Using Genetic Genealogy].
I think it's about time we started to think about the consequences.
Labels:
Genes
Gairdner Awards 2008
This is the week of the Gairdner awards. It's an excellent opportunity for undergraduates to see and hear some outstanding scientists. This week's lineup includes the 2008 winners and returning winners from past years.
Samuel Weiss: Adult neural stem cells
Victor Ambros: MicroRNA pathways in animal development
Gary Ruvkun: The tiny RNA pathways of C. elegans
Nahum Sonenberg: Translational control in biology and medicine
Harald zur Hausen: Infections as cancer risk factors
Ralph M. Steinman: Dendritic cells: A vehicle for vaccine development
Alan Bernstein: Progress towards an HIV vaccine
Sydney Brenner: An introduction
Craig Mello: RNAi from mechanism to medicine
Eric Olson: MicroRNa control of heart development and disease
George Church: Reading and writing genomes
Douglas Hanahan:Micro-RNA signatures in tumorigenesis
James S. Thomson: Exiting the pluripotent state, and back again
Gordon Keller: Directed differentiation of embryonic stem cells
Cynthia Kenyon: Genes and cells that regulate the lifespan of C. elegans
Leonard Guarente: Sirtuins, aging and diseases
The Gairdner Foundation presents a two-day symposium entitled "Minds That Matter" at the University of Toronto featuring academic lectures by Gairdner winners past and present, and other leading medical scientists. Attendance is open to anyone and is free of charge. All lectures are given at the Medical Sciences Auditorium on the University of Toronto campus in downtown Toronto.
TORONTO - UNIVERSITY OF TORONTO CAMPUS - MACLEOD AUDITORIUM
Date: Thursday, October 23, 2008
9:00 a.m.
Welcome: Dr. John Dirks, President, The Gairdner Foundation
Chair: Catharine Whiteside, Dean, Faculty of Medicine, Vice Provost Relations with Healthcare Institutions, University of Toronto
9:10 a.m.
Introduction: Dr. Freda Miller, Senior Scientist, Developmental & Stem Cell Biology, The Hospital for Sick Children, Professor, Department of Molecular Genetics, University of Toronto
Speaker: Dr. Samuel Weiss, Gairdner Laureate 2008, Professor of Cell Biology & Anatomy & Pharmacology & Therapeutics, Director Hotchkiss Brain Institute, University of Calgary, Calgary, AB, CA
Lecture: Adult neural stem cells: From basic science to therapeutic applications
9:50 a.m.
Introduction: Dr. Howard Lipshitz, Professor & Chair, Department of Molecular Genetics, Canada Research Chair (Tier 1) in Developmental Biology, University of Toronto, ON, CA
Speaker: Dr. Victor Ambros, Gairdner Laureate 2008, Professor of Molecular Medicine, University of Massachusetts Medical School, Worcester, MA, USA
Lecture: MicroRNA pathways in animal development
10:30 a.m.Break
10:45 a.m.
Introduction: Dr. Craig Smibert, Department of Biochemistry, University of Toronto
Speaker : Dr. Gary Ruvkun, Gairdner Laureate 2008, Department of Genetics, Harvard Medical School, Boston, MA, USA
Lecture: The tiny RNA pathways of C. elegans
11:25 a.m.
Introduction: Dr. Tony Pawson, University Professor, University of Toronto, Programme in Molecular Biology & Cancer, Samuel Lunenfeld Research Institute, Mount Sinai Hospital
Speaker: Dr. Nahum Sonenberg, Gairdner Laureate 2008, Professor, Department of Biochemistry and McGill Cancer Centre, McGill University, Montreal, Quebec, CA
Lecture: Translational control in biology and medicine
12:05 p.m. LUNCH
1:00 p.m.
Chair: Dr. Jack Gauldie, University Professor, Department of Pathology & Molecular Medicine, McMaster University, Director, Centre for Gene Therapeautics, Hamilton
1:05 p.m.
Introduction: Dr. Joan Murphy, Head of the Division of Gynecologic Oncology, UHN, Associate Professor, Department of Obstetrics & Gynecology, University of Toronto
1:10 p.m.
Speaker: Prof. Harald zur Hausen, Gairdner Laureate 2008, Deutsches Krebsforschungszentrum, Heidelberg, Germany
Lecture: Infections as cancer risk factors
1:40 p.m.
Introduction: Dr. Michael Julius, Vice President Research, Sunnybrook Health Sciences Centre, Toronto, CA
Speaker: Dr. Ralph M. Steinman, GairdnerLaureate 2003, Henry G. Kunkel Professor & Sr. Physician,The Rockefeller University, New York, NY, USA
Lecture: Dendritic cells: A vehicle for vaccine development
2:20 p.m.
Introduction: Dr. Janet Rossant, Chief of Research & Senior Scientist, Research Institute, The Hospital for Sick Children, Toronto, ON, CA
Speaker: Dr. Alan Bernstein, Gairdner Wightman Laureate 2008, Executive Director, Global HIV Vaccine Enterprise, New York, NY, USA
Lecture: Global solutions for global challenges: Progress towards an HIV vaccine
3:00 p.m. Dr. John Dirks
ConclusionADVANCES IN MOLECULAR BIOLOGY: MICRO RNA'S, STEM CELLS AND AGING
TORONTO - UNIVERSITY OF TORONTO CAMPUS - MACLEOD AUDITORIUM
Friday, October 24, 2008
9:00 a.m.
Welcome: Dr. John Dirks, President & Scientific Director, The Gairdner Foundation
Professor Paul Young, Vice President Research, University of Toronto, CA
Chair: Dr. Michael Hayden, Canada Research Chair in Human Genetics & Molecular Medicine, University of British Columbia, Vancouver, B. C.
Speaker: Dr. Sydney Brenner, Gairdner Laureate 1978 & 1991, Nobel Laureate 2002, Distinguished Professor, The Salk Institute, San Diego, CA, USA
Lecture: An introduction
9:30 a.m.
Introduction: Dr. Martin Simard, Laval University Cancer Research Centre, Quebec City, Montreal, CA
Speaker: Dr. Craig Mello, Nobel Laureate 2006, Gairdner Laureate 2005, Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, MA, USA
Lecture: RNAi from mechanism to medicine
10:10 a.m. Break
10:30 a.m.
Introduction: Dr. David MacLennan, Gairdner Laureate 1991, Banting Best Department of Medical Research, University of Toronto, Charles H. Best Institute, Toronto, CA
Speaker: Dr. Eric Olson, Professor, Molecular Biology, Southwestern Medical School, Dallas, Texas
Lecture: MicroRNa control of heart development and disease
11:10 a.m.
Introduction: Dr. Steve Scherer, The Center for Applied Genomics, The Hospital for Sick Children, Toronto, CA
Speaker: Dr. George Church, Professor of Genetics, Harvard Medical School, Director of the Center for Computational Genetics, Boston, MA, USA
Lecture: Reading and writing genomes
11:50a.m. LUNCH
12:45 p.m.
Chair: Dr. Michael Tyers, CH Waddington Professor of Systems Biology, The University of Edinburgh, Edinburgh, ScotlandIntroduction: Dr. Samuel Aparicio, Professor of Breast Cancer Research, UBC/BCCA, BC Cancer Agency, Vancouver, BC
Speaker: Dr. Douglas Hanahan, Diabetes, and Comprehensive Cancer Centres, UCSF, San Francisco
Lecture: Micro-RNA signatures of the stages in multi-step tumorigenesis
1:25 p.m.
Introduction: Dr. Brenda Andrews, Terrence Donnelly Centre for Cellular & Biomolecular Research, University of Toronto, Toronto, CA
Speaker: Dr. James S. Thomson, Professor of Anatomy, University of Wisconsin Stem Cell & Regenerative Medicine Center, Wisconsin, USA
Lecture: Exiting the pluripotent state, and back again
2:05 p.m.
Introduction: Dr. Andras Nagy, Senior Investigator, Developmental Molecular Geneticist, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, CA
Speaker: Dr. Gordon Keller, Senior Scientist, Division of Stem Cell & Developmental Biology, Ontario Cancer Institute, Toronto, CA
Lecture: Directed differentiation of embryonic stem cells to functional tissues
2:45 p.m.
Introduction: Dr. Peter Lewis, Vice Dean, Research & International Relations, Faculty of Medicine, Professor of Biochemistry, University of Toronto, Toronto, CA
Speaker: Dr. Cynthia Kenyon, Director, Hillblom Center for Biology of Aging, UCSF, San Francisco, CA
Lecture: Genes and cells that regulate the lifespan of C. elegans
3:25 p.m.
Introduction: Dr. Jacques Drouin, Chair in Molecular Genetics, Intitut De Recherches Cliniques De Montreal, Montreal, Quebec
Speaker: Dr. Leonard Guarente, Harvard Medical School, Boston, MA, USA
Lecture : Sirtuins, aging and diseases
4:10 p.m.
Conclusion: Dr. John H. Dirks
Labels:
Biochemistry
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Canada
Monday's Molecule #93
What's going on here? Your task is to identify the experiment that led to this result. It's a short step from there to this week's Nobel Laureate(s). You just need to switch species.
Here's a hint: This week's Nobel Laureate(s) and last week's Nobel Laureates have something in common.
You need to describe what you see in the figure as accurately as possible. Then identify the Nobel Laureate(s).
The first one to correctly identify the figure and name the Nobel Laureate(s), wins a free lunch at the Faculty Club. Previous winners are ineligible for one month from the time they first collected the prize. There are four ineligible candidates for this week's reward: Brad Hersh of Clemsen University, Alex Ling of the University of Toronto, Haruhiko Ishii, and Bill Chaney of the University of Nebraska.
THEME:
Nobel Laureates
Send your guess to Sandwalk (sandwalk (at) bioinfo.med.utoronto.ca) and I'll pick the first email message that correctly identifies the molecule and names the Nobel Laureate(s). Note that I'm not going to repeat Nobel Laureate(s) so you might want to check the list of previous Sandwalk postings by clicking on the link in the theme box.
Correct responses will be posted tomorrow. I reserve the right to select multiple winners if several people get it right.
UPDATE:The figure shows the result of an experiment where human cells in culture were irradiated with X-rays (Scherthan et al. 2008). There are two obvious chromosomal rearrangements. Breaks and deletions are common in X-ray treated cells. The Nobel Laureate is Hermann Muller who won the prize for creating mutants using X-rays. He worked with Drosophila melanogaster. Only one person got this one right and that person is ineligible.
[Figure Credit: The figure is from Scherthan et al. (2008)]
Scherthana, H., Hieberb, L., Braselmannb, H., Meinekea, V., and Zitzelsberger, H. (2008) Accumulation of DSBs in γ-H2AX domains fuel chromosomal aberrations. Biochemical and Biophysical Research Communications 371:694-697. [doi:10.1016/j.bbrc.2008.04.127]
Periannan Senapathy Publishes in PLoS ONE
I first encountered Periannan Senapathy on the sci.bio.evolution newsgroup. He was promoting the idea that the various animal phyla arose independantly rather than from descent from a common ancestor.
Here's one of his early postings on sci.bio.evolution from Feb. 13, 1995"
As a molecular biologist and genome researcher, I have enjoyed following the many ongoing debates in this and other forums over evolution theory -- both as a whole, and various aspects thereof. My own work in genome mechanics and genetic molecular structures has yielded much evidence pertaining to these debates, and over the years I have published several of my findings in PNAS, J Molec Biol, J Biol Chem, Nucleic Acids Research, Science and other journals.His ideas were eventually published in 1994 in a book with the following provocative title: "Independent Birth of Organisms. A New Theory that Distinct Organisms Arose Independently from the Primordial Pond, Showing that Evolutionary Theories are Fundamentally Incorrect." The book was published by "Genome Publications."
Until recently I have published these findings separately, although clearly they are all related. Now, however, I am publishing a single unified theory that incorporates all of these pieces -- and an enormous body of other evidence as well. This new unified theory proposes a radically alternative explanation for the origin and diversity of life on Earth, asserting that most of Earth's organisms must have originated independently in one primordial pond, and that the natural-selection mechanism described by evolution theories could have produced only minor variations among essentially similar species. These conclusions surely will provoke a lively debate in the scientific community, but a fair reading of the theory will show that it easily explains all of the available evidence -- molecular, biochemical, organismal and fossil -- and notably accommodates all of the contra-evolution evidence that has dogged evolutionists since Darwin.
Periannan Senapathy owns a company called "Genome International Corporation" which funds his work. The PLoS paper, for example, is funded by "Genome International Corporation" and the disclaimer reads, in part, "This project is purely an academic project, fulfilling the academic interest of the corresponding author, who owns the company." I don't know if the book is self-published.
The research article in PLoS ONE is ..
Regulapati, R., Bhasi, A., Singh. C.K., and Senapathy, P. (2008) Origination of the Split Structure of Spliceosomal Genes from Random Genetic Sequences. PLoS ONE 3(10): e3456 [doi:10.1371/journal.pone.0003456]It address an old problem about the origin of introns. The consensus among scientists these days is that introns arose late and they are derived from insertions of self-splicing RNA's into coding regions. These were subsequently copied into DNA and integrated into the genome. The similarity between Group II introns and spliceosomal introns lends strong support to this model.
The fact that bacteria have very few introns is consistent with the idea that introns arose late in evolution. As is the fact that introns positions are not highly conserved, as one might expect if they arose early.
The Senapathy paper tries to make the case that introns are primitive and the human genome, with lots of introns, is more primitive than bacterial genomes, which have lost their introns.
Speaking of losing, this issue was resolved over ten years ago when the last holdouts for "introns early" conceded defeat. Senapathy has not come up with anything that even remotely rejuvenates that losing position.
On a more troubling note, it's beginning to look as if PLoS ONE is attracting the kooks who find it easy to get their work published in that forum. It won't be long before I stop reading papers, and abstracts, from PLoS ONE.
Sunday, October 19, 2008
It's the Sequence, Stupid!
The latest issue of Science has an article summarizing the research done by Wilson et al. (2008). The "perspectives" article, by Hilary A. Coller and Leonid Kruglyak has a provocative title It's the Sequence, Stupid!. The Wilson et al. paper casts doubt on one of the current fads in molecular biology, namely the claim that there's something called "epigenetics" that trumps DNA sequence when it comes to determining gene expression.
Here's the abstract from the Wilson et al. (2008) paper. You be the judge.
Here's the abstract from the Wilson et al. (2008) paper. You be the judge.
Homologous sets of transcription factors direct conserved tissue-specific gene expression, yet transcription factor–binding events diverge rapidly between closely related species. We used hepatocytes from an aneuploid mouse strain carrying human chromosome 21 to determine, on a chromosomal scale, whether interspecies differences in transcriptional regulation are primarily directed by human genetic sequence or mouse nuclear environment. Virtually all transcription factor–binding locations, landmarks of transcription initiation, and the resulting gene expression observed in human hepatocytes were recapitulated across the entire human chromosome 21 in the mouse hepatocyte nucleus. Thus, in homologous tissues, genetic sequence is largely responsible for directing transcriptional programs; interspecies differences in epigenetic machinery, cellular environment, and transcription factors themselves play secondary roles.Grab some popcorn and a beer and sit back in your easy chair to watch how the evo-devo people talk themselves out of this one.
Wilson, M.D., Barbosa-Morais, N.L., Schmidt, D., Conboy, C.M., Vanes, L., Tybulewicz, V.L.J. Fisher, E.M.C., Tavaré, S., and Odom. D.T. (2008) Species-Specific Transcription in Mice Carrying Human Chromosome 21. Science 322: 434-438. [DOI: 10.1126/science.1160930]
The Powerful 7%
Here's the result from a US Gallup Poll taken in May, 2007 [Religion].
Only 7% are potential atheists. How powerful are those people? PZ Myers has the answer from an article by Melanie Phillips on the financial crisis in America [Pharyngula: You mean it's all my fault?].
I see this financial breakdown, moreover, as being not merely a moral crisis but the monetary expression of the broader degradation of our values - the erosion of duty and responsibility to others in favour of instant gratification, unlimited demands repackaged as 'rights' and the loss of self-discipline. And the root cause of that erosion is 'militant atheism' which, in junking religion, has destroyed our sense of anything beyond our material selves and the here and now and, through such hyper-individualism, paved the way for the onslaught on bedrock moral values expressed through such things as family breakdown and mass fatherlessness, educational collapse, widespread incivility, unprecedented levels of near psychopathic violent crime, epidemic drunkenness and drug abuse, the repudiation of all authority, the moral inversion of victim culture, the destruction of truth and objectivity and a corresponding rise in credulousness in the face of lies and propaganda -- and intimidation and bullying to drive this agenda into public policy.Makes you feel very sorry for the 93% who are being manipulated, doesn't it?
Death to Apostates?
There was a conference in the UK where a number of former adherents of Islam talked about the fact that rejecting Islam is a very serious offense. Apostates can be killed.
A.C. Graying wrote an article about the conference. It was published in The Guardian and you can read it on RichardDawkins.net.
Now Nesrine Malik has responded in Friday's issue of The Guardian [Death for apostasy?].
Here's part of what she says ...
As a Muslim who has lived most of my life in Muslim countries, this picture is hard to recognise. I have several friends and family members who are non-believers and apart from some efforts to return them to the straight and narrow or at least go through the motions of religious observance, they have not come into any physical danger. A close friend – hitherto religious – only recently sent me a long, tortured email detailing his journey away from Islam and from all religion; he expressed no fears for his life or safety, merely trepidation at the prospect of acclimatising to this new God-free world view.It's of little comfort to an ex-Muslim to learn that there is disagreement within the Muslim community about whether they should be put to death or not. They take only a little more comfort from the fact that the death penalty is only used "rarely."
Although the Council of Ex-Muslims and AC Grayling depict the threat to life and limb as an indisputable fact, in reality there are differences of opinion among Muslim scholars (ostensibly the hard core of the religion) regarding the death penalty for apostates.
This is not to say that Muslim governments – and Arab ones in particular – have a tolerant view of apostasy but the death threat is invoked only rarely and more for political reasons rather than religion ones: to set an example or to save face as a proxy punishment for challenging the social or political status quo. While this is in no way acceptable, it is an extension of the general lack of enshrined civic human rights and evolved political institutions and processes – a historical, social and geo-political reality in many Muslim countries that makes a mockery of any comparison to the experience of those renouncing Christianity or Judaism.
I admire Nesrine Malik for stating that killing apostates is "in no way acceptable" but she weakens her case a great deal by making excuses. Just because killing apostates is part of a larger intolerant viewpoint is an explanation, but not an excuse. Personally, I don't much care how the members of a cultural group run their lives but I draw the line when they interfere with others. People who leave the group are making a choice and they should be left alone.
Malik claims that many ex-Muslims try to make themselves into martyrs by claiming they have been threatened with death. They are just using "the emotive power of 'death for apostasy' to serve their own ends, be they personal or political." That may or may not be true—it probably is—but that's not the point.
The point is that outspoken Muslims like Nesrine Malik should make their opposition to 'death for apostasy' much clearer than just throwing away a phrase like "no way acceptable" to be immediately followed with a reason why it's understandable.
The Toronto Star Editorial Cartoon
Today's editorial cartoon in The Toronto Star is worth sharing. If Canadians were allowed to vote in the US Presidential elections, the McCain people would have waved the white flag months ago.
The Toronto Star Opposes PR, Again
I don't get it. Why are the editors of The Toronto Star against proportional representation? Their reasoning doesn't make sense.
Last year the editorial board opposed the Ontario referendum on electoral reform. Their arguments were so stupid and factually incorrect that "Public Editor" Kathy English was obliged to defend the newspaper's editorial opinions [The Toronto Star Defends Its Editorial Policy on MMP].
She didn't do a very good job.
Today The Star has an editorial opposing any proportional electoral system. The paper notes that a nationwide proportional system of voting would have given a different distribution of seats than the result of last Tuesday's election. They note that the Green party would have probably gotten a number of seats.
The editorial states, correctly, that we can't just recalculate the results based on Tuesday's voting because if we had voted under a proportional system people wold have voted differently. They say ...
Furthermore, the analysis is backward looking – transposing last week's results onto a new system. In all likelihood, if Canada had a system of proportional representation, the outcome would be very different, given the demographical and geographical diversity of the country. The pro-life Christian Heritage Party, for example, might win enough votes to get seats. And new parties might emerge to win seats – say, an Alberta First party or even ethnic parties.This is scary. It looks like the editors of The Star are afraid of proportional voting because (horrors!) some people might elect MP's who truly represent their points of view.
So Harper might be kept in power by entering a coalition with pro-life and Alberta First parties. Now that, indeed, is a scary prospect.
Now we certainly can't have that in a democracy, can we?
The scare tactics are not based on rational analysis of what happens in other countries. Most Western democracies have moved into the 21st century and they find it beneficial to let the people have their say. Sticking with an unfair first-past-the -post system only breeds disillusionment and bitterness with a system that disenfranchises a majority of voters. (Voter turnout on Tuesday dropped below 60%.)
It's time for The Toronto Star to find new editors—ones who are as progressive as the newspaper they work for. The current editors are clearly not up to the job.
But maybe we shouldn't expect too much from editors who put Madonna on the front page under a banner about a rape probe.
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Saturday, October 18, 2008
Barack Obama Is my Cousin!
George Bush and I share a common ancestor. This isn't as surprising as it might seem. Just about anyone in North America who has relatives from the British Isles will be able to trace some of their ancestors back five or six hundred years if they dig hard enough.
There's an excellent chance that you can connect at some point to several well-known lineages, usually those involving kings and queens. In my case I eventually hook up with Mary Stewart (1380 - 1458) who is the daughter of Robert III, King of Scotland. She married George Douglas (1376 - 1402).
George Bush descends from Mary's sister Elizabeth Stewart who married James Douglas, brother of George Douglas [The Ancestry of George Bush].1
Now, most of you might not be too excited about being related to George Bush but here's the good news ... I'm also related to Barack Obama according to Obama and Bush related.
That's pretty cool. It explains a lot.
1. It's possible that Bush descends from Beatrice Sinclair and not Elizabeth Stewart—the website is confusing. Even if this is an error there are several other connections.
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