Genetics & Molecular Biology

Behind every major scientific effort is a story. Beadle and Tatum's story is one of persistence. They began with a hypothesis: each gene causes the production of a single enzyme, and that enzyme catalyzes a biochemical reaction within an organism.

The seeds of this hypothesis were spawned by Sir Archibald Garrod, who reported in 1909 that alkaptonuria - an inherited condition in which the urine is colored dark red by the chemical alkapton - results from a single recessive gene, which causes a deficiency in the enzyme that normally breaks down alkapton.
Some fun with microscopes and fluorescent proteins: in the image below, you can watch what brewer's yeast does with its DNA as it reproduces itself. This is the microbe that ferments your beer and wine, and makes your bread rise.

"Are you confused by all the talk about DNA and genes? We can help," claims the University of Utah. There is now no excuse for not knowing what stem cells do, what messenger RNA is, why SNPs are important, or about any other hot topic in the news about the latest biomedical research. University scientists are getting into the online communication game, although in many cases they are doing it awkwardly. What else do you expect from a bunch of pointy-headed, tweed-wearing, absent minded nerds?
Mechanically, walking is a complicated feat.  We take for granted that a carefree cascade of one-footed falls adds up to steady rapid locomotion.

Replicating a dynamically stable foot-over-foot walk has become a holy grail for roboticists—remember the hype about ASIMO? Researchers at Penn State are taking a shortcut to nanoscale bipedal drones thanks to to motor proteins, the walking caravan molecules within our cells.
Prions first made their notorious media debut in the mid-1980’s when British cattle contracted Mad Cow disease. As a result, over 150 people in Europe were infected and died from the human form known as Creutzfeldt-Jakob disease—a fatal neurological disorder with similar symptoms as Mad Cow.

Although prions are infectious agents with a bad reputation, research suggests that prions also play a role in epigenetic regulation.  Recently, a Nature Cell Biology study conducted by molecular biologists at the University of Illinois at Chicago, discovered a new prion in yeast that raises further questions about the biological role of prions in gene regulation.
Insects such as honeybees and bumble bees are predictable in the way they move among flowers, typically moving directly from one flower to an adjacent cluster of flowers in the same row of plants. The bees' flight paths have a direct affect on their ability to hunt for pollen and generate "gene flow", fertilization and seed production that results when pollen moves from one plant to another. The study of gene flow has experienced more attention in part due to the recent introduction of genetically modified organisms (GMOs) into the environment.

We’re all aware of the severe genetic and unpleasant physical consequences that result from reproducing with a closely related relative.  Aside from unfortunate aesthetics, inbreeding can also lead to the extinction of small organismal populations.  This decrease of reproductive success is referred to as “inbreeding depression” and mechanisms that cause it are still being debated by biologists. 

Bell curves are everywhere. Pick 100 random people and measure them: measure their height, their weight, their blood pressure, their time to run a mile, or to sprint 50 yards, and their IQ, and you find that most of us fall in the middle of the spectrum, while there are always some people on either extreme. Why?

The puzzle grows deeper when you think about genetics. If a trait like height is controlled largely by genes, how is it that height falls into a bell-curve pattern? Bell-curves seem completely at odds with what we learn about the discrete genetics of Mendel's round and wrinkled peas in high school biology.

It turns out that the solution to this puzzle is fairly simple (although the details get messy). In fact, Darwin's cousin hit on the right answer (long before he or anyone else knew about Mendel's genetics), with what he called the "Supreme Law of Unreason": a bell curve is exactly what you expect when you toss together "a large sample of chaotic elements." In other words, genetics is like one big game of The Price Is Right.
I have always held a fascination for transposons, or jumping genes as they are sometimes called. Part of this interest may be due to my background in Drosophila genetics, where a transposon called a P element has been used extensively for genetic manipulation of flies for years.
It makes sense that ecological changes caused by humans affect natural biodiversity and, in some cases, can even cause permanent displacement of a species.

Unless science revives it.

Researchers from Eawag and from two German universities (Frankfurt and Konstanz), analyzed genetic material from Daphnia eggs up to 100 years old and say the eutrophication of Greifensee and Lake Constance in the 1970s and 1980s led to genetic changes in a species of water flea which was ultimately displaced. Despite the fact that water quality has since been significantly improved, this species has not been re-established.   Naturally, anyway.

Daphnia Galeata.  Photo: Eaweg University