I’ve just read a good book about genetics. The Making of the Fittest: DNA and the Ultimate Forensic Record of Evolution [1] by Sean B. Carroll. There is much food for thought in this book. One reviewer called it “A Primer of Evolutionary Theory for Beginners”, and this is accurate. One doesn’t need to know chemistry or physics to follow his reasoning, because he teaches the most necessary pieces.
Basically, this book examines what has turned up in studying the genomes of various species over the last couple of decades, as well as tracing genes from generation to generation in the same family line. It starts with a simple introduction to what DNA is, how it works, and how we know this. Then it gradually leads one to understand how genes transform from one generation to the next, and how this leads to speciation.
Basically, ever-present radiation, random chemistry, and aggressive biology cause frequent single-letter changes in DNA. Also RNA copy-and-paste errors regularly drop or duplicate entire gene sequences. After this see Darwin for how some mutations are explicitly preserved, some are inevitably removed, and most simply languish in or become fossil genes because there is no preference one way or the other. Carroll covers all this in many examples.
Carroll presents the simple probability and large numbers theory to illustrate the surprising speed at which populations can change, and then shows functioning (or no longer functioning) genes that have in fact visibly changed populations so rapidly.
This book gives plenty of ammo to those arguing against Creationists whose understanding of biological evolution might be along the lines of the Creationist apology: Evolution: The Fossils Say No! [2] That book seriously misrepresents what fossils are, how many there are, where they are found, and what they’ve been discovered to mean, when, and by whom. But its main claim is that evolution is a theory based only on fossils. The Making of the Fittest barely mentions fossils (outside of those within the genome) and completely supports and explains evolutionary theory.
What about “new” traits being spontaneously created where they weren’t before? Any Creationist or Intelligent Design advocate can tell you that new functional genes cannot spontaneously grow just by accident. Back to copy and paste. Have you ever hit Copy once, and then accidentally double-clicked Paste? I have. So does replicator RNA. Duplicated genes are (for example, given in the book in detail) responsible for color vision. Change a single DNA letter in an opsin gene, and color vision changes frequency, appears, or vanishes, depending on the letter and location. Many body parts or life functions arose from mutations to copies of genes with other functions. This book shows how that can happen, did happen, and how that is proved beyond any doubt.
If mutations are so common, why don’t we see this every day? Consider how DNA fingerprinting works. They examine a long stretch of a particular fossil gene sequence (one that isn’t affected by reproductive selection), and it will be different with every generation. Mutation is very common, when seen from the genes. But that isn’t part of this book; it is covered in another book I’d recommend: Genome: The Autobiography of a Species in 23 Chapters [3] by Matt Ridley.
If you would like to understand how evolution actually works (under the hood), then read The Making of the Fittest!
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