In the already unusual world of viruses, retroviruses stand out for being even more so. Called “retro” because they reverse the flow of genetic information from RNA to DNA, rather than the normal DNA to RNA, they have turned out to be ancient, omnipresent, and incredibly influential. They are also important as they cause diseases such as AIDS. With Discovering Retroviruses, Anna Marie Skalka delivers a book dedicated to this particular group that is as technical as it is fascinating.
Sea otters don’t eat algae. And yet, their diet influences the abundance of seaweed. How? Indirectly. Sea otters eating sea urchins (spiky animals in the same class as sea stars) eating kelp has become a textbook example of a trophic cascade, and Serendipity is a first-hand account by ecologist James A. Estes of how this happened. A trophic cascade refers to the indirect effects that ripple through a food web as a result of, for example, a predator consuming its prey. Simultaneously, the book is a searingly open account of how science is done, how ideas change, and how fortuitous events can suddenly send your research programme off in a whole new direction.
Beware the virus. If there is one message physician and evolutionary biologist Frank Ryan is hammering home with this book, it is this. Viruses are absolutely everywhere and more numerous even than microbes. So much so that Ryan speaks of the virosphere rather than the biosphere. But more than harbingers of disease, they are also agents of evolutionary invention. Now why does that sound familiar?
When I reviewed Planet of Microbes: The Perils and Potential of Earth’s Essential Life Forms, I remarked that microbes are everywhere. If you are willing to stretch the definition of life a bit further still, there is one entity that is even more numerous and omnipresent: the humble virus. We tend to think of viruses almost exclusively in the context of disease (see for example The Invisible Enemy: A Natural History of Viruses). But, as virologist and pharmaceutical researcher Michael Cordingley shows here, they are so much more than mere pathogens and have a huge influence on evolutionary processes in all organisms. This book paints a remarkable portrait of these unusual life forms.
Antibiotics have been saving human lives since the drug Salvarsan was discovered in 1932. Penicillin went into mass-production in 1942. This is not a long time when you think about it, but a world without the protection offered by them already seems unimaginable. Not only have they offered protection from diseases such as tuberculosis, and stopped infections following injury or childbirth, they have also allowed us to develop surgical techniques requiring immune system suppression such as organ transplants. However, careless use of antibiotics has accelerated evolution of drug-resistant bacteria such that we are about to lose their protection.