Genetics & Molecular Biology
A new study published in Genome Research has identified intrinsic properties of DNA that influence mutation rate, shedding light on an area of biology that still needs to be investigated - the mechanisms involved in genome maintenance .
Some DNA mutations are subject to natural selection, either conferring a biological advantage that is selected for, or a negative effect that is selected against. Mutations not under selection are said to be neutral, and the rate at which neutral mutations accumulate is reflective of the true DNA mutation rate. Researchers can estimate this mutation rate by comparing neutrally evolving sequences in species that share a common ancestor.
Scientists have long wondered what is happening at the cellular and molecular level to bring about the amazing coordination that occurs when birds migrate or fish gather in schools.
A team of researchers writing in Science has found evidence that this collective behavior can arise in cells that initially may not be moving at all, but are prodded into action by an external agent such as a chemical. Their study has shown that food-deprived amoebae are prodded into their coordinated clumping by the chemical cyclic adenosine monophosphate (cAMP), effectively changing the parameters of the cell environment.
Multiple sclerosis (MS) is a devastating autoimmune disease, where the immune system attacks the white matter throughout the nervous system. While the cause for MS is currently unknown, epidemiological data so far suggests that the disease is likely triggered by both environmental and genetic factors. To pinpoint the molecular mechanism for MS, Sergio Baranzini and colleagues at UCSF conducted a recent twin study on multiple sclerosis using advanced tools such as genomic deep sequencing analysis. In their study published recently in Nature, Baranzini analyzed immune cells from identical twins where one of the twins has developed MS (Barazini et al., 2010). Much to their surprise, the study found no significant genomic differences between the twins.
Researchers from the University of Barcelona and the University of California, San Francisco have captured the first high resolution images of DNA unfolding.
The team studied a small DNA fragment consisting of 12 base pairs (the human genomes has about 3,000 million base pairs) and obtained 10 million structural snapshots of how DNA unfolds. In this process they revealed the two main ways by which the natural folded structure move to an unfolded state. The results of the research were published in Angewandte Chemie.
Scientists have developed the first cell controlled by a synthetic genome which may allow them to probe the basic machinery of life and engineer bacteria specially designed to solve environmental or energy problems.
The research team, led by Craig Venter, has already chemically synthesized a bacterial genome, and transplanted the genome of one bacterium to another. Now, the scientists have put both methods together, to create what they call a "synthetic cell," although only its genome is synthetic.
Researchers have programmed an autonomous molecular "robot" made out of DNA to start, move, turn, and stop while following a DNA track.
The development could ultimately lead to molecular systems that might one day be used for medical therapeutic devices and molecular-scale reconfigurable robots---robots made of many simple units that can reposition or even rebuild themselves to accomplish different tasks.
Results of the research have been published in Nature.
The traditional view of a robot is that it is "a machine that senses its environment, makes a decision, and then does something---it acts," said Erik Winfree, associate professor of computer science, computation and neural systems, and bioengineering at Caltech.
I am constantly amazed at how pathologizing variable phenomena is usually a human social agent. Consider the XY fertile Akodon females who go roaming around in South America. No other rodents seem to have told these fertile XY females that they have a disorder of sex development (DSD). That will undoubtedly be left to some of the "powers that be" of the human species. Shall I say rats? Or shall I say of mice and men?
Scientists have identified two new genes that may be risk factors for the development of late-onset Alzheimer's disease (AD), according to a new paper in the Journal of the American Medical Association.
Using an intensive, genome-wide association analysis study (GWAS), the researchers identified two new genes at specific locations in the DNA called loci that reached the required genome-wide statistical significance threshold for the first time, thus identifying them as very likely associated with AD.
Neural stem cells have long been defined as origin of nervous system development, spontaneously giving rise to the heterogeneous multitude of cells that make up the brain. Remarkably, neural stem cells seem to have the uncanny sense to differentiate at the right time and place, and to the appropriate fate, to produce a complex network consisting of neuronal connections and supportive glial cells.
Researchers writing in Nature say they can have discovered how living cells use a limited number of genes to generate enormously complex organs such as the brain.
The team describes how a hidden code within DNA explains how a limited number of human genes can produce a vastly greater number of genetic messages. The discovery bridges a decade-old gap between our understanding of the genome and the activity of complex processes within cells, and could one day help predict or prevent diseases such as cancers and neurodegenerative disorders.
The researchers developed a new computer-assisted biological analysis method that finds 'codewords' hidden within the genome that constitute what is referred to as a 'splicing code'.