I just finished a fascinating read about the evolution of dogs over at the ScienceBlog Observations of a Nerd.  Having read quite a bit about evolution including Darwin’s founding work, I found the discussion of dogs very interesting.  Darwin spent significant time on the subject of domesticated animals in On The Origin of Species.  He was wrong about the fact that dogs originated from multiple species, but fortunately he was right about everything else.

Observations of a Nerd tells a fascinating story about the evolution of wild dogs in Moscow.  Apparently they have evolved into four general breeds of dogs with specific traits.  This highlights how extreme conditions can accelerate the normally slow pace we associate with evolution.

Here is a cool simulation of what would have occurred to Apollo 13 had they not corrected course.

The true nature of DNA was discovered in 1953 by James D. Watson and Francis Crick, two giants of the scientific world.  Crick, who also did work in physics and and neuroscience, established the central model of how DNA “controls” the cell, or what has become known as the Central Dogma of molecular biology.  The general idea is that DNA makes RNA, and RNA makes protein, and protein interacts with any number of processes in the cell.  The model has been refined over the years, but the core tenets still stand.

An important part of the DNA <-> RNA -> Protein model is RNAi, or RNA interference.  RNA provides a couple of mechanisms that allow interference of what parts of the DNA (genes) are being expressed (turned-on) in a cell, and to what extent those that are turned on influence cellular processes.  RNAi is important in the development and day-to-day (or minute-to-minute) running of a cell.  It is also an important mechanism for fighting off viruses and other invaders of the cell.

Because RNAi can be used to turn-down or turn-off functions in the cell, it has long been seen as a possible weapon against disease.  For example, cancer cells could be targeted with RNAi from outside the cell and reproduction or mutation could be halted.  In this way cancer cells could be killed.  This same technique could be used to guard against viruses and other genetic pirates of the molecular biology world.

One problem with this approach has been the inability to correctly target only those cells that one wishes to affect.

Nanotechnology has a history filled with more speculation and hypothesis than experimental science and real use.  However, in recent years nanotech and medicine have seen a couple of breakthroughs that might result in new therapies for disease.  A breakthrough last year showed how gold nanoparticles can been used in conjunction with radiation to treat cancer.  And now researches at  CalTech have demonstrated nanobots that accurately deliver RNAi to melanoma cells (cancer).  This type of chemical deliver has huge promise.

The fight against cancer has always been waged with blunt instruments.  Chemotherapy attacks the cancer, but it also attacks healthy systems in the patient.  The same is true of radiation treatments.  Surgery is invasive and often ineffective.  But the delivery of specific chemical compounds to very specific locations within the body (individual cells!) could see the battle against cancer and other diseases gaining a very precision weapon.