Charles Darwin proposed that all life evolved from “one primordial form”. This means that humans are related to even the simplest and evolutionarily oldest organisms. The interrelatedness of all life has important implications for how we understand the inner workings of our biology and for how we develop therapies to treat the thousands of diseases that plague our species.
The common ancestor theory has two important implications. First, we share the information encoded within our genes with all other life forms. A gene is a small section of a large double helix DNA molecule. Genes are instructions for making proteins, and proteins mediate virtually all biological processes. Since we share our genes with all organisms, we also must share our biology with them.
Second, evolution is a process that increases the complexity of life forms over time. Whatever our common ancestor was, it was a bare bones form of life, probably something that did little more than store and copy genetic information. Over time, genes are distorted by mutations that occur when DNA is damaged or copied incorrectly. Most mutations are either inconsequential or harm the organisms that harbor them. However, mutations will occasionally give rise to new and advantageous biological functions that enable an organism to exploit new environments and resources. As new biological functions are added, complexity increases.
How does any of this impact human health? If the biology of all life is related, it stands to reason that we can gain essential insights into human biology and disease by studying organisms that don’t even remotely resemble us. The diversity of life generated by evolution provides scientists with many unique and powerful experimental models. Studying less complex organisms speeds the pace of discovery and reduces research costs. In some cases, certain organisms make it possible to do experiments that could not be done otherwise. For example, the first detailed understanding of the electrical signals used by our nerve cells to communicate with each other and the rest of the body came by studying giant nerve fibers from squid. These fibers allowed physiologists to measure and manipulate nerve cell electrical activity in ways not readily possible in other animals. Our understanding of this electrical activity underlies all of modern neuroscience and neuromedicine. The tiny roundwormC. elegansgrows easily and inexpensively in the laboratory, produces abundant offspring, can be studied using powerful genetic methods and has a lifespan of only 2-3 weeks. These characteristics allowedC. elegansbiologists to identify the first genes that influence how long we live thus opening the door to the development of therapeutic tools for slowing the degenerative changes associated with aging.
By: Ma. Estelita C. Labahan
