Genetics & Molecular Biology

A variant of the alcohol dehydrogenase enzyme ADH1B*3 is associated with reduced rates of alcohol dependence (AD), according to a study in Alcoholism: Clinical&Experimental Research.

The enzyme variant appears to cause sedation and reduce the amount alcohol a person will drink.  ADH1B*3 is found almost exclusively in populations with African ancestry, the study's authors say.
Using ancient DNA preserved in bones from Siberian mammoths 25,000 to 43,000 years old, scientists have brought the primary component of the specimens' blood "back to life."

The seven-year research effort, detailed this week in Nature Genetics, reveals special evolutionary adaptations that allowed the mammoth to cool its extremities down in harsh Arctic conditions to minimize heat loss.

The findings will also help scientists study the DNA of other extinct species, such as Australian marsupials.

If you ever looked at the inside of a computer, you would find intricate wirings and connections. But the computer is essentially useless until you’ve downloaded all the necessary software and applications. In a way, this analogy could be applied to the workings of the brain. The brain is essentially a circuitry consisting of billions of neuronal connections (or synapses) that is infinitely more complex than the typical computer hardware.
Molecules called microRNA can silence genes that protect the genome from cancer-causing mutations, say Ohio State researchers writing in PNAS. Their study shows that microRNA-155 (miR-155) can inhibit the activity of genes that normally correct the damage when the wrong bases are paired in DNA.

The loss or silencing of these genes, which are called mismatch repair genes, causes inherited cancer-susceptibility syndromes and contributes to the progression of colorectal, uterine, ovarian and other cancers.

"Our findings suggest that miR-155 expression might be an important stratification factor in the prognosis and treatment of cancer patients," says Dr. Carlo M. Croce, from Ohio State's Human Cancer Genetics program.

Multiple sclerosis (MS) is an equal opportunity destroyer. It attacks the central nervous system and eventually renders most patients disabled. Among its high-profile victims are celebrated cellist Jacqueline du Pre, whose career was ended by MS, and Joan Didion, one of America's greatest writers — but they are far from alone.

The National MS Society estimates that there are currently about 400,000 cases in the U.S. and more that 2 million suffer from the disease over the world. Although there is currently no cure, a breakthrough finding from a Tel Aviv University scientist and physician may lead to earlier diagnosis, more effective intervention, and perhaps even a cure for the autoimmune disease.

A new study of embryonic stem cells shows that mammalian genes may all have a layer of control that acts like the pause button on your DVR, previously thought to be a peculiarity of particular genes.

The research demonstrates that the infamous cancer gene c-Myc plays a major role in the pause release of many genes throughout the genome and may have practical application in the treatment of some of the nastiest cancers.

The findings were reported this week in Cell.

The primary structure of a protein also sometimes referred to as a polypeptide, is decided by sequences of amino acids. The amino acids are sequenced in a linear polypeptide chain which folds as it is being produced. it is this three - dimensional folded structure that decides the proteins biological activity.

A team of virologists have discovered important details about a genetic mechanism pathogenic viruses use to evade the immune systems of their hosts. They say their results could point the way to new treatments that use the viruses' own trick against them. The research is detailed in Cell Host and Microbe.

The mechanism is based on the production of short RNA molecules (microRNAs) by the virus. RNA is chemically related to the genetic material DNA, and full-length RNA copies of gene sequences specify the structures of all cell proteins. MicroRNAs (miRNAs), on the other hand, play a crucial role in regulating gene expression.
Researchers studying the differential expression of microRNA say they may have discovered a way to treat autism by reversing the effects of the disease.

Taken together with recently published research regarding “DNA tagging” by methylation, they say their new study in Genome medicine illustrates two different “epigenetic” mechanisms controlling gene activity in autism that lie beyond genetic mutations. While methylation inhibits gene expression at the level of DNA, microRNA inhibits at the level of RNA.

MicroRNA are snippets of RNA, each of which can inhibit the expression of hundreds to more than a thousand genes. The effects of microRNA are also reversible by treatment with complementary “anti-sense” RNA.
In the field of regenerative medicine, embryonic stem cells are considered the “mother cells” that can replace virtually any type of tissue that are damaged or lost as a result of injury of degenerative diseases[1, 2]. This could be attributed to the ability of ES cells to differentiate into a wide range of cellular lineages that make up organs and tissues of the entire body.

Although this has caused much excitement in the field of regenerative medicine, a sobering fact is that ES cells are very scarce as they can only be obtained in the inner cell mass of an early stage embryo[1]. Moreover, the quest for ES cells in humans also raise ethical concerns that have driven ES cell research to a standstill.