Influenza, SARS, Ebola, HIV, the common cold. All of us are quite familiar with these names. They are viruses—a little bit of genetic material (DNA or RNA) encapsulated in a protein coat. But what we don't really understand, and what scientists have struggled with since the study of virology began, is whether viruses are actually living or not. A paper published today in Science Advances just might change that. By creating a reliable method of studying viruses' long evolutionary history—hitherto nearly impossible—researchers have found new evidence that strongly suggests viruses are indeed living entities.
On a genetic level, all of life on Earth speaks the same language. We've all got DNA and/or its close cousin, RNA. All of our genetic material is composed of the same batch of basic nucleotides, which are often called by the first letters of their full names—A, C, G and T for DNA; A, C, G and U for RNA. All cells on Earth even read those letters in much the same way, socells from different species are often able to read each other's DNA. That's how pharmaceutical companies are able to put the human gene for insulin into bacteria and yeast to produce insulin medicine for diabetics. Want see a gross example? Early in thehistory of genetics, some biologistsput the human gene for eyes onto a fruit fly's leg... and the fruit fly's cells made a fruit fly eye.
Scientists have long theorised that herpes viruses are so stuffed with genetic material that infecting a host cell is as easy as popping a balloon. Or exploding a powder keg. The internal pressure within the virus is so great, it explodes its genetic material straight out of its virus shell and right into its desired host.
The human immunodeficiency virus' capsid is both a shield and an open backdoor. Located in the center of every HIV particle, the capsid protects the virus' load of genetic material. Once the virus has entered a human cell, the capsid is programmed to come apart in an orderly way, kicking off the virus' takeover of the cell.
Scientists have produced the world's first chimeric monkeys, developed from stem cells harvested from separate embryos. They contain genetic material from as many as six genomes. The infant rhesus monkeys are totally healthy and could hold great promise for future stem cell research in primates, researchers say. They also carry an interesting and controversial message for future stem cell research: Those cultured stem cell lines in labs throughout this country, such a crucial scientific tool and such a cultural flashpoint, may not be as potent as the ones inside embryos.
