After a thorough two-year investigation, researchers at UC San Diego and the University of Oregon have identified over 70 genes that play a role in the repair of neurons after injury, specifically when it comes to the growth of axons. A massive genetic screening of 654 genes suspected to be involved, resulted in the identification of 70 genes that promote axon growth and 6 that inhibit it.

Retroviral proteases are a class of enzymes that play an important role in the maturation and proliferation of the AIDS virus. As such, this class of enzymes is a subject of intense research. The efforts, however, were hindered by a fundamental problem: nobody knew exactly what these enzymes looked like.

Recently, a lot of attention has gone to epigenetics, or heritable changes in gene expression caused by mechanisms other than changes in DNA sequence. An example of such a mechanism is DNA methylation, where a methyl group (CH₃) binds to cytosine or adenine. Epigenetic changes might explain the discrepancies that are being discovered between what the genetic code dictates and how an organism actually looks and functions, ranging from flower shape to the tendency for obesity.

What is life? As tough questions come, this is a good one. It seems simple at first, but even after great advances in biology and a sizeable increase in understanding how life works, there appears to be no real consensus on life. To quote Carl Sagan:

A research team at John Hopkins Medical Institutions has introduced synthetic chromosomes into yeast (Saccharomyces cerevisiae, see figure 1), in an effort to better understand how genomes work, and potentially allow some ‘control’ at genome level. As part of the synthetic yeast genome project, or Sc2.0, the researchers have introduced a synthetic right arm of the ninth chromosome, synIXR, and a partially synthetic left arm of the sixth, semisyn-VIL.

Figure 1: S. cerevisiae.

(Source: Wikimedia Commons, user: Masur)

Sex determination is obviously an important developmental event with great ecological and evolutionary consequences. A large variety of sex determination mechanisms exists, and the evolution of many of these is still relatively poorly understood. Previous work suggests that compensatory adaptations to mutations in involved genes might be relevant in the evolution of these pathways.