Researchers at Albert Einstein College of Medicine of Yeshiva University were able to watch, in real time, the process of gene transcription. They used florescent proteins to track the mRNA activity by inserting DNA sequences into a gene in live yeast cells. RNA made from these sequences bound a modified green fluorescent protein; expression of the entire gene resulted in mRNA molecules that were visible with fluorescent light. By monoriting the activity of RNA polymerase scientists were able to directly observe and measure the key steps involved in transcription: initiation, elongation, and termination. By observing how transcription works in the cells of yeast, we are better able to determine steps of the same processes in humans. For instance, one element researches saw was that initiation was a random event. “By contrast, once initiation occurs, RNA polymerase recruits individual nucleotides for the growing mRNA molecule in an efficient and predictable manner” said Dr. Singer.
Research by scientists from the Max Planck Institute for Developmental Biology in Tübingen, have shown reduction in genome size in close relative plants in the genus Arabidopsis. They used the Thale cress plant, the most widely studied flowering plant in genetics, and its relative the lyre-leaved rock cress. Both plants shared a common ancestor around ten million years ago and their lineages have sinced divereged. The genome of the thale cress has been decoded to have 125 million base pairs and includes 27,025 genes distributed on five chromosomes. The lyre-leaved rock cress produced a base pair sequence with 207 million base pairs or letters which is over 50 percent bigger than that of the thale cress. Scientists are thinking that the difference between the two species, in term of their number of genes, is not that significant because the lyre-leaved rock cress has around 32,670 genes distributed on eight chromosomes. They also say considerable parts of the thale genome have been lost. Although many differences are accounted for through small deletions in the transposons, sequences of DNA that can move, other elements are still being lost from the thale genome. They also consider the fact that the lyre-leaved rock cress has eight chromosomes and conclude the thale cress genome is a “more streamlined genome as the form derived through evolution.” Through their analysis, the scientists have laid the foundations for further insights into how evolution in plants can take effect on the level of genes and molecules.
The article describes the research done by scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany. Humans were found to have three different gut types as well as microbial genetic markers. These bacterial genes could one day be used to help diagnose and predict outcomes for diseases like colo-rectal cancer, while information about a person’s gut type could help inform treatment. Everyone has bacteria in their gut; however, the number of different types of bacteria vary from person to person.
“We found that the combination of microbes in the human intestine isn’t random,” says Peer Bork, who led the study at EMBL: “our gut flora can settle into three different types of community – three different ecosystems, if you like.”
The study consisted of a total of 124 people from three different continents and three gut types, or enterotypes, were identified. These gut types seem to be independent of traits like age, gender, nationality and body-mass index. However, the guts of older people seem to have more microbial genes involved in breaking down carbohydrates. This could be because bacteria take up the task in order to survive in the gut. When diagnosing likelihood of a patient contracting a disease, doctors could look for clues not only in the body but also in the bacteria that live in it. After diagnosis, treatment could be adapted to the patient’s gut type to ensure the best results.
Researchers at the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), part of the National Institutes of Health, began to discover reasons behind muscle degeneration and ways to prolong its’ effects. While reading an article about their research, the question was asked why patients with Duchenne muscular dystrophy (DMD) have very little problems through childhood and adolescence, yet succumb to the disease in adulthood. It was also asked why elderly people who lose muscle strength following bed rest find it difficult or impossible to regain. They started exploring possibilities by researching into satellite cells. While satellite cells actively increase muscle mass during infancy, they decrease in number and become inactive unless activated by injury or degeneration. Scientists than looked into a gene called Ezh2, known to keep the activity of other genes in check. When they genetically inactivated Ezh2 in satellite cells of laboratory mice, the mice failed to repair muscle damage meaning satellite cells could not proliferate. Ezh2 expression is known to decline during aging. If scientists could find therapies to continue Ezh2 expression and continue the production of satellite cells, they could increase the lifespan and quality of life in DMD patients and the elderly.
“We will not be able to cure the muscular dystrophies with this approach because the mutation in the gene that causes the diseases would remain. But certainly, if we can extend the period in which the satellite cells proliferate and compensate for the underlying defect, we might increase the lifespan of people with muscular dystrophy. We could certainly increase their quality of life,” said Dr. Sartorelli ( Senior investigator in the NIAMS Laboratory of Muscle Stem Cells and Gene Regulation and lead author of the study).
The article explains the research done by Professor Dr. Peter Lichter of the German Cancer Research Center and his team. Pilocytic astrocytoma, the most common brain tumor in children, is usually slow-growing and benign. Lichter has found that in most cases of pilocytic astrocytoma there is a defect in the BRAF gene. The team packed the defected gene with a virus and placed it into cells of mice. 91% of animals treated resulted in a pilocytic astrocytoma tumor. The defective BRAf gene constantly transmits growth signals into cancer cells. Now that we know the BRAF gene is a main component of pilocytic astrocytoma, new tests can be done with kinase inhibitors and other drugs to slow cancer cell growth.
Tissue section of a mouse brain with a pilocytic astrocytoma. The brown staining indicates astrocytes.
Recent studies have shown people with certain genotypes are more likely to drive after drinking than people with other genotypes. Doctors at UNT Health Science Center’s School of Public Health conducted a study in a bar district of a large college campus community. Random samples of saliva were taken from patrons leaving bars and results showed that patrons with S/S genotype are more likely to drive home from the bar than patrons with L/L genotype. The 5-HTTLPR genetic marker is commonly reported in three forms based on allele length: L/L (two long alleles), S/L (one long and one short allele), and S/S (two short alleles).Most research has shown that the S/S type is associated with psychological distress and problem behavior. Approximately 20 percent of the general population has the S/S trait. Although this does not give people an excuse to drink and drive it gives us a better understanding into the minds of repetitive DUI offenders. Individuals with this genotype are more apt to performing risky behaviors and impulsive decisions.
Darwin’s “tree of life” metaphor for the process of evolution has been has been challenged by Antonis Rokas and Jason Slots’ discovery of a jumping gene cluster in this article. Although it was previously thought that genes were passed from parent to child, known as vertical gene transfer, Rokas and Slot found a cluster of 23 genes that have moved from one species of fungus to another. Horizontal gene transfer had previously been seen in bacteria with very rare exceptions in complex organisms such as fungi and animals. This jumping gene cluster codes for a toxic compound called sterigmatocystin. Revealing this transfer has brought up new ideas about evolutionary paths and the changing of individual species. Many horizontal gene transfers have resulted in drug-resistant bacteria. Methods for surviving a drug are able to be passed to one another. This discovery has lead to more research into past evolutionary pathways as well as current evolving species.