Genetics & Molecular Biology

How should we talk about biological networks or systems? Roger Brent and Jehoshua Bruck stated the problem like this: The search for biologically relevant formalisms has a chance to greatly affect the understanding of biological function, in ways we are just starting to imagine. Today, by contrast with descriptions of the physical world, the understanding of biological systems is most often represented by natural-language stories codified in natural-language papers and textbooks. This level of understanding is adequate for many purposes (including medicine and agriculture) and is being…

PEPcase determinations As a key enzyme in C4-photosynthesis and Crassulacean Acid Metabolism (Kluge, 1983), phosphoenolpyruvate carboxylase (EC 4.1.1.31) has been studied intensively in several laboratories, particularly in the last decade. In most studies, the reaction catalyzed by PEPCase (PEP + HCO~- Mg2+, oxaloacetate + Pi) is coupled with malate dehydrogenase (EC 1.1.1.37) to the oxidation of NADH (oxaloacetate + NADH ~ malate + NAD + ) and the enzymic activity is measured by the rate of decrease in absorbance at 340 nm (Lane et al. 1969). Direct measurements of oxaloacetate, either by…

Instead of using someone else's urine in random drug testing, perhaps criminals can step it up a notch on the scientific ladder and use someone else's genome. Can your genes ever absolve you of responsibility for a particular act? New Scientist features a story that asks that very question, regarding the case of a man whose sentence was reduced because he had "gene variants linked to aggression." In 2007, Abdelmalek Bayout admitted to stabbing and killing a man and received a sentenced of 9 years and 2 months. Last week, Nature reported that Pier Valerio Reinotti, an appeal court judge in…

Scientists have successfully differentiated human embryonic stem cells (hESC) into major cell types of lung epithelial tissue, a technique which could provide an alternative to lung transplants for patients with lung injury due to chronic pulmonary disease and inherited genetic diseases such as cystic fibrosis. Lindsey Van Haute and colleagues from the Department of Embryology and Genetics at the Free University of Brussels (Vrije Universiteit Brussel) demonstrated for the first time that hESC could be converted into epithelial-like cells in human models. Van Haute and colleagues assessed…

The development of molecular techniques for genetic analysis has led to a great augmentation in our knowledge of crop genetics and our understanding of the structure and behavior of various crop genomes. These molecular techniques, in particular the applications of molecular markers, have been used to scrutinize DNA sequence variation(s) in and among the crop species and create new sources of genetic variation by introducing new and favorable traits from landraces and related crop species. Markers can aid selection for target alleles that are not easily assayed in individual plants, minimize…

Are accident rates higher for people with a particular gene variant?    Bad drivers may, in part,  have their genes to blame, suggests a new study by UC Irvine neuroscientists. People with a particular gene variant performed more than 20 percent worse on a driving test than people without it – and a follow-up test a few days later yielded similar results. About 30 percent of Americans have the variant. This gene variant limits the availability of a protein called brain-derived neurotrophic factor (BDNF) during activity. BDNF keeps memory strong by supporting communication among…

Nepotism has a bad connotation in the workplace or French politics but being surrounded by relatives does lead to better group dynamics and more cooperation in some animals, and certainly spiders, according to a new study published in BMC Evolutionary Biology. In a new study, the researchers found that Stegodyphus tentoriicola spiders are far more efficient at foraging for food and cooperate better when they’re related to each other and, as with humans and other animals, relatedness may favor the evolution of less selfish behavior, more collaboration and better group dynamics. Jutta Schneider…

"Speciation is one of the most fascinating, unsolved problems in biology," says Harmit Malik, Ph.D., an associate member of the Hutchinson Center's Basic Sciences Division.   The first appearance of new beings on Earth - the mystery of mysteries - is a great puzzle for scientists and philosophers alike. The “mystery of mysteries” phrase related to speciation is often attributed to Charles Darwin but was used in a February 20, 1836 letter from John Herschel to Charles Lyell, in which Herschel wrote “that mystery of mysteries the replacement of extinct species by others.”  In "On the…

Lightweight drinkers rejoice, it may be nature that keeps you from pounding shots like Indiana Jones squeeze Marion in "Raiders of the Lost Ark". Researchers at North Carolina State University have found a genetic 'switch' in fruit flies that plays an important role in making flies more tolerant to alcohol.  If you're reading this site, you will not that doesn't automatically translate to humans but a counterpart human gene contributes to a shift from metabolizing alcohol to the formation of fat in heavy drinkers. This shift can lead to fatty liver syndrome – a precursor to cirrhosis. In…

The human heart, a tireless organ that beats within our chests continuously for decades, continues to amaze me, in spite of my having studied it for several years now.  My continued amazement stems not from the fact that this muscle functions for so long, and for the most part without us being aware of it (although this is indeed phenomenal), but from the rich variety of behavior that it exhibits across multiple scales.  When I was first introduced to the heart, it was essentially as a ball of muscle divided into four chambers that were separated by valves.  Newly oxygenated…