Genetics & Molecular Biology

When the DNA sequences of Homo sapiens and Pan troglodytes were sequenced, the difference between the sequences of coding genes was smaller than expected based on the phenotypic differences between both species. If not the coding genes, then what is responsible for these dissimilarities?     (Source: godlessgeeks.com)     In the words of the authors of a new study that took a look at this question: Although humans and chimpanzees have accumulated significant differences in a number of phenotypic traits since diverging from a common ancestor about six to eight million…

Scientists have discovered more about the intricacies of Natural Killer cells, a unique type of white blood cell important in early immune responses to tumors and viruses.   Unlike most cells of the immune system that are activated by molecules found on the pathogen or tumor, Natural Killer cells are shut down by a group of proteins found on healthy cells. These de-activating proteins, known as Human Leukocyte Antigens or HLA molecules are absent in many tumors and cells infected with viruses, leaving them open to attack by the Natural Killer cells.  Natural Killer cells…

For millenia, science and technology have been mobilized toward a Utopian dream; making food so plentiful and cheap poor people could afford to be fat. Well, they can, and because we have freedom (sort of - some states ban trans fats for your own good) a lot of people are fat; so fat some advocates even insist we should go back to making food too expensive for poor people to eat.  Others contend people should just eat less and keep government out of it. For people who seek a third alternative, there is the awesome power of science.  Maybe taking a pill would do the trick.  A…

Some genes appear to have an effect on lifespan. This shouldn’t be too surprising news. But now, a research team from Stanford has shown that there are epigenetic effects on longevity as well. Using the nematode Caenorhabditis elegans, a beloved model organism in aging research, they have shown that some changes in chromatin states in a parental generation can affect the lifespan of their descendants. More specifically, they looked at the regulatory complex H3K4me3, which is composed out of ASH-2, WDR-5 and SET-2, and responsible for adding methyl-groups to the H3 histone. It has been shown…

Earlier this year, a DNA computer was reported that could calculate square roots. A little later, a neural network was constructed out of ‘the stuff of life’. These advances strongly hinted at the possibility of using biochemicals in order to do computational operations. Now, a new study, published in Nature Communications, presents another step towards this goal. A research team from Imperial College in London has created biological logic gates in Escherichia coli. To achieve this, the team used genetics to devise a logical AND gate (see figure 1). In short, environmental signals can bind to…

The genome of the medieval form of Yersinia pestis, the pathogen responsible for the Black Death in Europe between 1347 – 1351, has been reconstructed. A surprising finding is that the genes affecting its virulence apparently haven’t changed all that much between then and now. A research team has used teeth gathered from a burial ground know to contain a lot of Black Death victims to reconstruct the genome of the medieval form of Y. pestis. After the genomic reconstruction, the researchers compared their ‘ancient pathogen’ to the extant forms of the bacterium (see figure 1). In their words:…

At first sight, the hand held tablets and screens hosted on nurse tables and held dearly to the palms of able clinical staff, may appear to be incongruous with the functional obligations of their owners and you could be forgiven to mistake them for Apple’s new iPad. Yet, it is not an uncommon sight, to find them as reverential backpacks and requisite arsenal in the hands of medical personnel, almost akin to the ubiquitous mobile phone. Electronic health records or EHRs as they are widely known across the medical community have largely served as useful substitutes of patient case pads and…

Number crunchers have never been much of nature lovers. Most venture capitalists, as it were, would rather be content, mulling over their wins and losses in the vagaries of business transactions of a life sciences company, than showering encomiums on the potential benefits of a technology that could potentially double up as a silver bullet for debilitating diseases such as diabetes, cancer or AIDS. In principle thus, financial speculators and their markets, have little patience for technologies that do not offer tangible monetary benefits. While biologists have relied heavily on favors of…

Stem cells by virtue of their potential for self renewal and capacity to differentiate into diverse cell types have remained a primordial force in ensuring evolution of the species and sustenance of organs.While stem cells derived from embryos are totipotent by nature; conditioned reprogramming at the nuclear level owing to differential expression of pattern forming genes, potentially divert embryonic stem cells towards two fates. The well charted course for most embryonic stem cells is to completely differentiate into dedicated cell types that form the bulk and mass of organs and organelles…

A meta-analysis has provided support to the previously suggested idea that a certain gene's variation is linked to suicidal behavior. The gene in question is the one that codes for BDNF (or brain-derived neurotrophic factor), a protein that performs the role of growth factor in nervous system development. After comparing 11 studies and adding data they had gathered themselves (resulting in a total of 3352 people, of whom 1202 had a history of suicidal behavior), the authors were able to confirm that people with the methionine (see figure 1) variation of the gene ran a higher risk of…