Genetics & Molecular Biology

Spider silk is lightweight and stretchy yet has tensile strength greater than steel. Its chemistry is just as fascinating. Silk proteins, called spidroins, must convert from a soluble form to solid fibers at ambient temperatures, with water as a solvent, and at high speed. How do spiders achieve this astounding feat? A new paper discusses how the silk formation process is regulated.  Spidroins are big proteins of up to 3,500 amino acids that contain mostly repetitive sequences, but the most important bits for the conversion of spidroins into silk are the ends. These terminal…

Physicists have identified a mechanism that may help explain Zipf's law – a unique pattern of behavior found in disparate systems, including complex biological ones. Their mathematical models demonstrate how Zipf's law naturally arises when a sufficient number of units react to a hidden variable in a system. Zipf's law is a mathematical principle named for 20th-century linguist George Zipf, though noticed as far back as the 19th century. Zipf found that if you rank words in a language in order of their popularity, a strange pattern emerges: The most popular word is used twice as often as the…

Your stress levels may be another thing you can blame on your mother. Scientists investigating pregnancies in four generations of rats show that inherited epigenetic effects of stress could affect pregnancies for generations.  The researchers believe that these changes are due to epigenetics - the arrangement and expression of our genes. In most cases this refers to DNA methylation of the nucleotide base pairs. In this study the researchers believe the epigenetic changes are due to microRNA (miRNA) - non-coding RNA molecules that play a role in regulating gene expression.…

Tuber melanosporum - black or Périgord truffles - are fungi that grow in symbiosis with the roots of oak and hazelnut trees. In the world of haute cuisine, they are expensive and highly prized. Epigenetics is the study of changes in gene expression caused by mechanisms other than changes in the DNA sequence. In the world of epigenetics, black truffles are of major interest because of their unique pattern of DNA methylation, a biochemical process that chemically modifies nucleic acids without changing their sequence.  A newly published reports on the truffle's unique genetic makeup. "The…

Credit: University of Arizona Researchers have sequenced the complete genome of Oryza glaberrima (African rice), which will enhance scientists' and agriculturalists' understanding of the growing patterns of African rice, as well as enable the development of new rice varieties that are better able to cope with increasing environmental stressors to help solve global hunger challenges. In analyzing the 33,000 genes that make up the African rice genome, researchers discovered that during the process of domestication, Africans and Asians independently selected for many of the same genetic traits…

About 15% of adults suffer from fertility problems, primarily due to genetic factors. This is something of an evolutionary paradox; wouldn't natural selection have caused people with infertility to not reproduce?Various theories explain the survival of harmful mutations: A gene that today causes obesity, for example may have once granted an evolutionary advantage; or a disease-causing gene may persist because it is passed on in a small, relatively isolated population. Dr. Moran Gershoni of the Weizmann Institute of Science decided to investigate another approach – one based on differences…

Using data from over 18,000 patients, scientists have identified more than two dozen genetic risk factors involved in Parkinson's disease, including six that had not been previously reported.  Affecting millions of people worldwide, Parkinson's disease is a degenerative disorder that causes movement problems, including trembling of the hands, arms, or legs, stiffness of limbs and trunk, slowed movements and problems with posture. Over time, patients may have difficulty walking, talking, or completing other simple tasks. Although nine genes have been shown to cause rare forms of…

In 2012, scientists involved in the ENCODE (Encyclopedia of DNA Elements) project stated that 80% of our genome is functional - that it has some biochemical function.  The finding was controversial, with critics arguing that the biochemical definition of 'function' was too broad - just because an activity on DNA occurs, it does not necessarily have a consequence. For functionality, you need to demonstrate that an activity matters.  An Oxford University group took advantage of the ability of evolution to discern which activities matter and which do not and they identified how much of…

Researchers have successfully used a new and potentially safer method to stimulate ovulation in women undergoing IVF treatment.  One in six couples in the UK experiences infertility, and 48,147 women underwent IVF treatment in 2011.  To make eggs mature, doctors normally administer the hormone, hCG but in some women, there is a risk that this can overstimulate the ovaries, with potentially life-threatening consequences.  Ovarian hyperstimulation syndrome (OHSS) affects around a third of IVF patients in a mild form, causing symptoms such as nausea and vomiting. Less than 10 per…

The International Wheat Genome Sequencing Consortium recently published a chromosome-based draft sequence of wheat's genetic code - its genome. The genetic blueprint of bread wheat, also known as common wheat, is an invaluable resource to plant science researchers and breeders  because it is grown on more than 531 million acres around the world and produces nearly 700 million tons of food each year, said Eduard Akhunov, associate professor of plant pathology at Kansas State University. "For the first time, they have at their disposal a set of tools enabling them to rapidly locate…