Genetics & Molecular Biology

Most previous neural networks consisted out of a physically connected network of neural cells. But can a soup of interacting molecules also show brain-like behavior? Apparently, it can. Researchers at Caltech (the same team that, a little over a month ago, made a DNA computer that can calculate square roots) created a neural network of four neurons, each made out of 112 distinct DNA strands. This network was subsequently ‘trained’ to recognize four scientists, whose identities were represented by a set of specific answers to four yes/no questions. The network, then, tried to identify one of…

New research has found that some of the human X chromosome originates from Neanderthals and is found exclusively in people outside Africa. Neanderthals, whose ancestors left Africa somewhere in the range of 400,000 to 800,000 years ago, evolved in what is now France, Spain, Germany and Russia, and are believed to have lived until about 30,000 years ago.  Early modern humans left Africa about 80,000 to 50,000 years ago. The question on everyone's mind has always been whether the physically stronger Neanderthals, who possessed the gene for language and may have played the flute, were a…

I confess. I'm jealous of frogs, lizards and salamanders. Why? Because of their stem cells and transdifferentiation potential. Compared to them, us humans are pathetic in terms of our ability to heal ourselves, regenerate body structures, and change our bodies. I was out taking a hike here in Yolo County today along Putah Creek.  In the last two weeks the place has been literally crawling and hopping with critters including lizards and frogs. Baby frogs and grown up frogs. I saw an interesting looking spotted frog and took a picture with a zoom lens. I thought I probably had a good…

I confess. I'm jealous of frogs, lizards and salamanders. Why? Because of their stem cells and transdifferentiation potential. Compared to them, us humans are pathetic in terms of our ability to heal ourselves, regenerate body structures, and change our bodies. I was out taking a hike here in Yolo County today along Putah Creek.  In the last two weeks the place has been literally crawling and hopping with critters including lizards and frogs. Baby frogs and grown up frogs. I saw an interesting looking spotted frog and took a picture with a zoom lens. I thought I probably had a good…

Editing DNA holds great promise, but like all new technologies that are still in their infancy, it’s still slow, expensive and hard to use. However, researchers are developing genome-scale editing tools that might aid in quickly and easily rewriting the genomes of living cells. Harvard-based researchers have developed a new way to edit the genome of living bacteria. What they did, was replace one three-letter sequence (or a codon) in the genome with another one (for all codons, see figure 1). Codons act as code (what’s in a name, huh?) for amino acids, or as stop signal. Using E. coli, one of…

In a letter to Nature, Mark Ptashne, Oliver Hobert, and Eric Davidson question an editorial that appeared in the journal (Nature). The editorial, focused on the International Human Epigenome Consortium, and says that it is “clear that epigenetics … could explain much about how similar genetic codes are expressed uniquely in different cells, in different environmental conditions and at different times.” However, Ptashne, Hobert, and Davidson say that epigenetic marks stem from the DNA sequence and its interations with RNA and proteins. “They are thus directly dependent on the genomic sequence…

A Democratic president banned the use of federal money for human embryonic stem cell (hESC) research, a Republican president restricted federal hESC funding to existing lines and a Democratic president continues to limit federal money for hESC research.   Who is regarded as anti-science on this issue? Republicans. I know, I know, Democrats are anti-science on plenty of other things - animal research, agriculture, vaccines and a whole list of others - but this is just about hESC research and there it is clearly just a Republican issue.   The mainstream media and science bloggers say…

The naked mole rat (or Heterocephalus glaber) (see figure 1) is a strange mammal. As their name already implies, they have little hair. Furthermore, their eyes are very small and their visual abilities are mediocre at best. This naked rat is one of only two eusocial mammals (the other one being the Damaraland mole rat, or Fukomys damarensis), with a lifestyle similar to social insects. Living in underground colonies, ruled by the only reproductive female (the ‘queen’), the work is performed by non-reproductive females. A few males hang around, mating with the queen. They live in a huge…

The image of a stoner always having the munchies is a stereotype because it's true - and it's true, say researchers, because it has a basis in biology. Daniele Piomelli, Nicholas DiPatrizio and colleagues found that fats in foods like potato chips and french fries trigger a biological mechanism - and that is driven by natural marijuana-like chemicals in the body called endocannabinoids. In their study, they discovered that when rats tasted something fatty, cells in their upper gut started producing endocannabinoids but sugars and proteins did not have this effect. The process starts on the…

Botany: A Blooming History And now we come to part three of this series 3. A Hidden World which is the world of the genes. However, this is a massive topic, and I’m going to split into two parts, roughly discovery and application. The first clues were to come from a monastery garden. The monastery was Augustinian Abbey of St Thomas in Brno, where worked Gregor Mendel (1822 – 1884). His experiments with peas are now famous, and according to Wikipedia: Mendel did read his paper, Versuche über Pflanzenhybriden (Experiments on Plant Hybridization), at two meetings of the Natural History Society…