Molecular Biology
grrlscientist | March 14, 2008tags: genetics, Bill Nye the Science Guy, education, streaming video
Those of you who do not know who Bill Nye the Science Guy! is will especially enjoy this video. In this streaming episode, Bill Nye the Science Guy explores the science behind genes (part 2). Basically, you can thank your parents for all those nice pairs of genes. Chromosomes are made up of sequences of genes, which are themselves made up of strands of DNA. The mutations in DNA during replication cause resulting changes within genes, which is the basis of evolution. The third and last part appears tomorrow morning. [6:17].
grrlscientist | March 13, 2008tags: genetics, Bill Nye the Science Guy, education, streaming video
Those of you who do not know who Bill Nye the Science Guy! is will especially enjoy this video. In this streaming episode, Bill Nye the Science Guy explores the science behind genes (part 1). Basically, you can thank your parents for all those nice pairs of genes. Chromosomes are made up of sequences of genes, which are themselves made up of strands of DNA. The mutations in DNA during replication cause resulting changes within genes, which is the basis of evolution. [7:53].
pharyngula | March 2, 2008
What are the key innovations that led to the evolution of multicellularity, and what were their precursors in the single-celled microbial life that existed before the metazoa? We can hypothesize at least two distinct kinds of features that had to have preceded true multicellularity.
The obvious feature is that cells must stick together; specific adhesion molecules must be present that link cells together, that aren't generically sticky and bind the organism to everything. So we need molecules that link cell to cell. Another feature of multicellular animals is that they secrete…
evolgen | March 1, 2008I'm easily annoyed. A lot of things piss me off. Here are the things that irked me today:
Fake St. Patrick's Day. A large drinking school schedules Spring Break the same week as St. Patty's Day, and they do it two years in a row. This pisses off the students because it costs them an official drinking day (they'll be drunk on spring break regardless if it's St. Patrick's day). So, the students schedule their celebration of St. Patrick's day for the weekend before Spring Break. There's a few hundred drunk douchebags walking around town in green shirts and stupid hats today. It's goddamn…
pharyngula | February 17, 2008
Since I wrote about the wacky creationist who couldn't wrap his mind around the idea that plants and animals are related, and since I generally do a poor job of discussing that important kingdom of the plants (I admit it, I'm a metazoan bigot…but I do try to overcome my biases), I thought I'd briefly mention an older review by Elliot Meyerowitz that compares developmental processes in plants and animals. The main message is that developmental processes, the mechanisms that assemble the multicellular whole, are very different in the two groups and are non-homologous, but don't get confused:…
grrlscientist | February 13, 2008tags: researchblogging.org, evolution, bird-dinosaur split, dinosaurs, birds, rocks-versus-clocks, fossil record, molecular clocks
The first feathered dinosaur fossil found in China -- Sinosauropteryx.
The feathers can be seen in the dark line running along the specimen's back.
Image: Mick Ellison, AMNH [larger view]
There is a lot of controversy among scientists regarding when modern birds first appeared. The current fossil record suggests that modern birds appeared approximately 60-65 million years ago when the other lineages of dinosaurs (along with at least half of all terrestrial…
pharyngula | February 3, 2008Many of you have already seen the gorgeous video below: it's a spectacularly beautiful animation of the activity in a cell.
I like it, and it's a useful illustration, but … there's something fundamental that it gets completely wrong. So today I'm not going to praise it, I'm going to criticize it. It's a substantial criticism, too, one that means I wouldn't show this video in my classes without spending more time explaining the error than it takes to show it.
Here's the central problem: molecules don't behave that way. What is portrayed is wonderfully precise movement; it looks like the…
pharyngula | January 23, 2008When I decide to take a break from the mad scramble of organizing my classes, I really shouldn't follow a whim and take a peek at Uncommon Descent. The lead article has this astonishing opening paragraph.
Remember the dark days of vestigal organs? You know, back when there was a list of 180 vestigal organs? Or remember the days of junk DNA - when repetitive DNA, large regions of non-protein-coding DNA, and all sorts of mobile DNA were assumed to be non-functional simply because the investigators had assumed Darwinism rather than design?
I'm half a century old. I remember a lot of things, but…
pharyngula | January 11, 2008…you think the PCR song is kind of catchy.
The PCR Song
There was a time when to amplify DNA,
You had to grow tons and tons of tiny cells.
Then along came a guy named Dr. Kary Mullis,
Said you can amplify in vitro just as well.
Just mix your template with a buffer and some primers,
Nucleotides and polymerases, too.
Denaturing, annealing, and extending.
Well it's amazing what heating and cooling and heating will do.
PCR, when you need to detect mutations.
PCR, when you need to recombine.
PCR, when you need to find out who the daddy is.
PCR, when you need to solve a crime.
(…
evolgen | January 11, 2008Let's pretend this never happened:
Those are the Scientists for Better PCR, complete with their own wanna-be Boss. Because when you need to find out who the daddy is, you turn to PCR.
grrlscientist | December 10, 2007tags: James Watson, racism, African ancestry, genetics, genome, deCODE Genetics
James Watson, 1962 Nobel Prize winner
for co-discovering the structure of DNA along with
Francis Crick and Maurice Wilkins.
This is one of the funnier things I've read recently. It turns out that 1962 Nobel laureate, James Watson, who recently made some disparaging comments about the intelligence of Africans, probably is of African descent himself.
Watson, whose genome was completely sequenced, is the second person whose entire genome was published on the internet. As a result, it is freely accessible to the…
mark_antimony | December 6, 2007I've spent this last week familiarizing myself with this article for my biochemistry class. Obviously, the article is way to large to bite off in one blog. One spot that draws my curiosity.
The AUR1 is promoted by the presence of Galactose. The kicker is that the presence of Glucose will turn off the gene. The organism is unable to live without the target sphingolipids. Is there some reason for this? I would think that adaptation would have long since accounted for this. Weird.
grrlscientist | November 29, 2007tags: birds, bird sex chromosomes, ZZ, ZW, parrots, sex identification, molecular biology
Evolution of Avian and Mammalian sex chromosomes.
Image: E.R.S. Roldan and Montserrat Gomendio "The Y chromosome as a battle ground for sexual selection" Trends in Ecology & Evolution 1999, 14:58-62.
You all are probably curious to know what is happening with my birds these days, so I shall tell you about how sex is identified in birds, such as parrots, where the sexes look the same. But wait a minute, you ask, what does an update about my birds have to do with identifying sex in parrots?
You…
evolgen | November 29, 2007PLoS ONE has recently published a paper entitled "Beyond the Gene" by Evelyn Fox Keller and David Harel, in which the authors take a stab at the long standing question: What is a Gene? Because this is such a big picture question, the appropriate discussion of the paper would involve a synthesis of what they authors wrote, what has previously been written, and what I think about all of that. I'm not going to do that. I'm too lazy and too stupid to do that. Instead, I'm going to read the paper and live-blog it. This one's for you, Bora.
Quick tip: If you're planning to read an entire paper,…
evolgen | November 27, 2007I came across two press releases yesterday, entitled:
Entire Yeast Genome Sequenced
and
University of Toronto scientists map entire yeast genome
Upon reading the first, I thought, hasn't the entire genome of Saccharomyces cerevisiae already been sequenced? And haven't other yeast genomes been sequenced as well? What in the world could they be referring to? Did yet another yeast species gets its genome sequence? Does that really warrant a press release (sorry Jason)? And the second made me think that the person in charge of titling the press release decided that genome sequencing is synonymous…
neurophilosophy | November 7, 2007
Researchers from the National Institute on Aging in Baltimore have produced an "atlas" of the activity of nearly 17,000 genes in 5 different regions of the mouse central nervous system.
Using microarrays, the NIA team measured the levels of mRNA transcripts in the cortex, hippocampus, striatum, cerebellum and spinal cord. Samples were taken from young, middle-aged and old-aged mice of both sexes, and maintained on either a normal or a calorie restricted diet.
In this way, the transcriptome of each region, or the whole repertoire of mRNAs found in each region, was obtained. The…
grrlscientist | November 6, 2007tags: researchblogging.org, supermouse, Phosphoenolpyruvate Carboxykinase, PEPCK-C, glucose metabolism
Like a Lance Armstrong equivalent among ordinary mice, a group of American scientists report that they altered a single gene involved in glucose metabolism in a mouse and discovered that this genetically altered mouse demonstrates remarkable athletic abilities. For example, this supermouse runs 20 meters per minute for five hours or more without stopping -- a distance of 3.7 miles (6 kilometers)!
"They are metabolically similar to Lance Armstrong biking up the Pyrenees. They utilize…
neurophilosophy | October 31, 2007
Researchers from Harvard University have developed a remarkable genetic technique that enabled them to visualize complete neuronal circuits in unprecedented detail, by using multiple distinct colours to label individual neurons.
The technique, called Brainbow, works in much the same way as a television uses the three primary colours to generate all the colour hues. With multiple combinations of up to four differently coloured fluorescent proteins, a palette of approximately 100 labels has been produced.
To develop Brainbow, the researchers used the Cre/loxP site-specific recombination…
grrlscientist | October 24, 2007tags: book review, biotechnology, biomedicine, stem cells, ethics, Cloning: A Beginner's Guide, Aaron Levine
Would you drink milk from a cloned cow?
Should we clone extinct or endangered species?
Are we justified in using stem cells to develop cures?
When will we clone the first human?
Ever since Dolly the sheep was born, questions like these have been part of the public consciousness, and now, cloning is poised to revolutionize medicine, healthcare, and even the food we eat. Regardless of what certain politicians do to slow the progress of scientific research, cloning is here to stay, and…
pharyngula | October 8, 2007I've known for years that this was going to happen: Mario Capecchi, Oliver Smithies and Briton Martin Evans have won the Nobel Prize in Medicine for their work on targeted gene mutations. If you're interested in what kinds of work they've done, I described one paper on Hox regulatory evolution, and this work on the evolution of the Hox code wouldn't have been possible without their knockout techniques.