Wherever you go in the world, whatever animal, plant, bug, or blob you look at, if it is alive, it will use the same dictionary and know the same code.  All life is one.

~ Matt Ridley, author of Genome: The Autobiography of a Species

Underneath the complexity of many organisms is an elegant simplicity, a beauty and unity that pleases both scientists and artists. For many multicellular organisms, life begins during fertilization when the genetic contents of the egg and sperm – each carrying half of the genetic material of the mother and father respectively – are united in a single cell. This unicellular embryo will go on to develop into a complete multicellular organism, with an enormous complexity of tissues and a diversity of cell types that carry out distinct roles. The unity here is that all the information for this elaborate process is carried within the DNA of that initial single cell formed during fertilization. All cells of the embryo will contain exactly the same genetic information encoded in the DNA. Thus, organisms that have descended from the primordial cell in which the structure of DNA first arose are “stuck” with this design, as if they are dictated by a biological version of the hoped-for “theory of everything” in physics. There’s more…

When a gene is found in a wide range of organisms, it is likely to play a similar basic role in those different organisms. This is another demonstration of biological unity, this time across species. For example, we share more than 60 percent of our genes with the fruit fly in spite of their evolutionary divergence of over 600 million years! And at least 90 percent of our genes are similar to those in the field mice. So, DNA and its protein-forming cousin, RNA run across all of nature – humans, animals and plants.

The material for this essay is based on Benny Shilo, Life’s Blueprint: The Science and Art of Embryo Creation, Yale University Press, 2014.