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Cell Biology

Minimal Cell More Complex Than Expected
January 3, 2006
Craig Venter’s lab has been working on an interesting project in theoretical biology: what is the minimum set of genes needed for life?  They have taken one of the simplest organisms, Mycoplasma genitalium, and knocked out genes to see which ones are essential and which are nonessential for viability.  (This is part of the “top […]
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Genetics

How Blind Cave Fish Lose Color
December 26, 2005
A study on cave fish revealed that several populations can have mutations to the same gene.  A gene that produces melanin, named Oca2, was found to be mutated in two separate populations of cave fish, resulting in albinism.  This same gene can produce albinism in humans. The replicated experiment is a powerful tool for experimental […]
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Origin of Life

Don’t PNA in our OOL
December 17, 2005
Theories for the origin of life (OOL) are in a crisis, unable to imagine how something as complex as a replicating cell could come into existence. Could PNA do it?
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Cell Biology

Micro-RNAs are Cell’s Optimizers
December 12, 2005
“Unnoticed next to the main ingredients, microRNAs were considered to be ‘junk’ DNA, leftovers from millions of years of evolution.”  That line comes from an article on EurekAlert telling about how dramatically that picture has changed.  RNA molecules are now seen to be indispensable, with many roles in the cell.  This article talked about how […]
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Genetics

Genes Attack the Trees
November 26, 2005
Evolutionary tree-building (11/14/2005) is a tangled business.  Now that scientists can compare genomes of diverse animals, they can compare the resulting molecular evolutionary trees with traditional ones – those produced by inferring relationships based on outward (morphological) characteristics of living or fossil organisms.  What happens when the trees don’t match?     Two recent studies, […]
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Genetics

Does Gene Expression Evolve?
November 17, 2005
“Mutation is the ultimate source of biological diversity because it generates the variation that fuels evolution,” wrote four scientists in Nature November 10.1  Conventionally, theorists have focused on gene mutations for that fuel; what about mutations to gene expression?  That’s what they set out to discover.     One would think that positive natural selection […]
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Birds

March of the Little Penguins Down Darwin Lane?
November 10, 2005
Penguins are on people’s minds since the movie, but there are other species of the handsome-yet-funny waddlers besides the reigning emperors.  The news media are saying one species demonstrates evolution – another word on the public mind these days.  MSNBC News talked about “Penguin evolution,” and Science Now proclaimed “Evolution on Ice.”  Actually, it’s only […]
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Genetics

Genome Complexity No Measure of Evolution
November 7, 2005
Do genes show an increasing pattern of complexity from lower to higher organisms?  Not necessarily, reported Elizabeth Pennisi in Science Now.  Cnidarians, including sea anemones and corals, for example, show almost as much complexity in their genomes as humans, whereas fruit flies and worms, seemingly more complex than cnidarians (06/25/2005, 2nd par.) appear to have […]
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Dumb Ideas

Listen to Yourself Evolve
October 23, 2005
A pretty gene is like a melody, decided Mary Anne Clark at Texas Wesleyan University, so she gave life to music—literally.  She translated the structure of proteins into musical notes so that she could hear “protein songs,” reported National Geographic News.  By listening to the songs, scientists and students alike can hear the structure of […]
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Cell Biology

Can Networks Design Themselves?
October 4, 2005
A molecular biologist and a physicist at the Weizmann Institute of Science in Israel (see also 09/26/2003) wrote a paper in PNAS1 with an intriguing title: “Spontaneous evolution of modularity and network motifs.”  Can a network arise spontaneously?     Biologists increasingly speak of the interaction of genes, proteins and metabolic processes in terms of […]
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Genetics

Alternative Gene Splicing May Be Common
September 23, 2005
Scientists at MIT publishing in PNAS1 detected instances of alternative splicing in over 1,000 genes of stem cells.  They also computed possible isoforms of mRNA transcriptions and found 80% of them in the cells.  Not only that, the isoforms (alternatively spliced versions of exons from the same gene) appeared to be functional: “We find that […]
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Cell Biology

Cell Has Automatic Jam-Clearing Proofreading Machinery
September 19, 2005
Findings at Rockefeller University have scientists excited.  DNA copying machines work on a “sliding clamp” that can hold two repair machines at the same time.  One is a low-fidelity repair tool, the other a high-fidelity repair tool.  Usually, the high-fidelity one is active, but when it needs a bigger hammer that is perhaps more effective […]
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Botany

Reader Project: Calculate the Speed of Plant Package Delivery
September 9, 2005
Get out your pencil and hand calculator.  A team of Swedish and French scientists measured the velocity of a message traveling on the intraplant internet (see 08/12/2005, 11/09/2004, 10/04/2004 and 07/13/2001 entries).  Publishing in Science,1 they believe they have witnessed a signaling molecule, in the form of a messenger-RNA (mRNA; see yesterday’s entry) moving through […]
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Genetics

RNA Research Uncovers a Previously Ignored Universe of Genetic Information
September 8, 2005
A slow revolution is occurring in the study of genetic information.  Until recently, the only interesting items in DNA sequences were the genes – the genetic codes for proteins.  Since these usually represented only a small fraction of an organism’s genome, it was assumed the rest of the material was “junk DNA” – sequences that […]
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Early Man

Men Aren’t Going Extinct – Yet
September 3, 2005
Not long ago, evolutionary biologists were predicting the demise of manhood (see 11/01/2001, 03/31/2004).  The idea was that the Y chromosome, with no redundant copy (unlike the female’s two X chromosomes, and all others) appeared to be shriveling up and mutating itself out of existence.  Now that the chimpanzee genome has been published (see 09/01/2005 […]
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