Saving Your Brain The Revolutionary Plan to Boost Brain Power, Improve Memory, and Protect Yourself Against Aging and Alzheimer's

CHAPTER 1 Adam's and Eve's Brains My theory would give zest to recent & Fossil Comparative Anatomy: it would lead to a study of instincts, heredity, & mind heredity . . . --Charles Darwin; personal notebook, 1837;his first inkling that evolution helps explain the mind and brain Why did brains evolve? What are they for? It may not be immediately obvious how these questions relate to saving our brains, but they do, for one important reason: evolution explains aging-related brain changes. The very word evolution conjures images of misty pasts and private events, the astonishing tales of trillions of creatures over billions of years, meeting, embracing, stirring a new life into being and with it a DNA dynasty. At some point in that incredible story, a human Adam and Eve appeared, the first of their kind, with brains exactly like ours. Of course, the lucky mutations that led to humanity may have occurred several times before human beings really took hold as the world's dominant hominids; it's even possible that humans arose independently in several places and that our mental image of one Adam and Eve is a fine romance rather than a biological fact. But most likely, at some point between 100,000 and 200,000 years ago, the first few babies who had truly human brains were born. They were the founders of the world's human population--our genetic Adams and Eves. Evolution is responsible for how human brains came to be, why they flourished, and why they are vulnerable to change with age. Indeed, the evolution of the brain--its genes, its neurons, the dazzling expansion of its cortex, the niche we evolved to fill at the edge of some long-ago forest, and even the way we have strayed from the lifestyle for which evolution prepared us--is the real explanation for why our brains are likely to get into trouble as we grow older. That story began in the molecular Garden of Eden. Fruits from the Garden Life at its most basic level is an organism's ability to make copies of itself, using the magnificent DNA molecule as a sort of biological copy machine. We've all seen pictures of DNA shown as a double helix that looks like a long, twisted ladder. Our genes are strung out along the DNA ladder, one after another, in a carefully determined sequence. Though scientists assumed for decades that there were more than 100,000 human genes, one of the most humbling findings of the recently completed Human Genome Project has been that it probably takes only about 40,000 genes to make a human, not many more than it takes to make a worm. Yet these genes on human chromosomes carry the basic instructions that make us us--and that make every one of us different from everyone else. But life is not just a matter of genes. As impressive as the Human Genome Project has been, it only lets us peek at the blueprints of life. In order for these gene-blueprints to make anything useful in the body, they must first be translated into proteins. Proteins are molecules that are manufactured based upon the precise blueprint instructions from our genes. But even after a protein is manufactured, it's still not ready for work; it must first be folded into an amazingly complex shape if it's ever going to do its job. A misfolded protein works about as well as a crumpled paper airplane--it falls quickly with a disappointing thud. It can even act as a poison. As we will see very soon, misfolded proteins are probably the secret of many aging-related problems in the brain, including Alzheimer's. Contrary to the popular vision of DNA as the fixed and stable essence of life, genes are changing all the time. Such changes are called mutations; they can affect everything from eye color to height, brain size to behavior, and they occur spontaneously, randomly, sheerly by chance. Mutations are one of the clever ways that nature changes our DNA in a busy and continuous trial-and-error form of genetic engiVictoroff, Jeffrey is the author of 'Saving Your Brain The Revolutionary Plan to Boost Brain Power, Improve Memory, and Protect Yourself Against Aging and Alzheimer's' with ISBN 9780553109443 and ISBN 0553109448.