In the United States: Professor Daniel Lieberman of Harvard University; Professor Nina Jablonski of Penn State University; Dr. Leslie J. Stein and Dr. Gary Beauchamp of the Monell Chemical Senses Center in Philadelphia; Dr. Allan Doctor and Dr. Michael Kinch of Washington University in St. Louis; Dr. Matthew Porteus and Professor Christopher Gardner of Stanford University; and Patrick Losinski and his helpful staff at the Columbus Metropolitan Library in Columbus, Ohio.
In the Netherlands: Drs. Josef and Britta Vormoor, Professor Hans Clevers, Dr. Olaf Heidenreich, and Dr. Anne Rios of the Princess Máxima Center for Pediatric Oncology in Utrecht. Special thanks also to Johanna and Benedikt Vormoor.
I am also much indebted to Gerry Howard, Dame Gail Rebuck, Susanna Wadeson, Larry Finlay, Amy Black, and Kristin Cochrane at Penguin Random House, to the brilliant artist Neil Gower, to Camilla Ferrier and her colleagues at the Marsh Agency in London, and to my children Felicity, Catherine, and Sam for much willing assistance. Above all, and as always, my greatest thanks go to my dear and saintly wife, Cynthia.
NOTES ON SOURCES
The following is intended as a quick guide for those who wish to check a fact or do further reading. Where a fact is commonly known or widely reported—the functions of the liver, for instance—I have not cited the source. On the whole, sources are listed only where assertions are specific, arguable, or otherwise distinctively notable.
CHAPTER 1: HOW TO BUILD A HUMAN
Altogether, according to RSC calculations: The information on the cost of building a replica Benedict Cumberbatch was supplied by Karen Ogilvie of the Royal Society of Chemistry, London.
We need, for instance, just 20 atoms: Emsley, Nature’s Building Blocks, 4.
We now know that selenium makes two vital enzymes: Ibid., 379–80.
you can irremediably poison your liver: Scientific American, July 2015, 31.
in 2012 Nova, the long-running science program on PBS: “Hunting the Elements,” Nova, April 4, 2012.
Well, you blink fourteen thousand times a day: McNeill, Face, 27.
The length of all your blood vessels: West, Scale, 152.
if you formed all the DNA in your body: Pollack, Signs of Life, 19.
You would need twenty billion strands of DNA: Ibid.
Its chemical name is 189,819 letters long: Ball, Stories of the Invisible, 48.
Nobody knows how many types of proteins: Challoner, Cell, 38.
All humans share 99.9 percent of their DNA: Nature, June 26, 2014, 463.
My DNA and your DNA will differ: Arney, Herding Hemingway’s Cats, 184.
about a hundred personal mutations: New Scientist, Sept. 15, 2012, 30–33.
One particular short sequence, called an Alu element: Mukherjee, Gene, 322; Ben-Barak, Invisible Kingdom, 174.
Five out of every six smokers: Nature, March 24, 2011, S2.
between one and five of your cells turns cancerous: Samuel Cheshier, neurosurgeon and Stanford professor, quoted on Naked Scientist, podcast, March 21, 2017.
Our bodies are a universe of 37.2 trillion cells: “An Estimation of the Number of Cells in the Human Body,” Annals of Human Biology, Nov.—Dec. 2013.
There are thousands of things that can kill us: New Yorker, April 7, 2014, 38–39.
We undertake every part of the process: Hafer, Not-So-Intelligent Designer, 132.
CHAPTER 2: THE OUTSIDE: SKIN AND HAIR
“Our seams don’t burst”: Jablonski interview, State College, Pa., Feb. 29, 2016.
We shed skin copiously, almost carelessly: Andrews, Life That Lives on Man, 31.
We each trail behind us: Ibid., 166.
acne, a word of very uncertain derivation: Oxford English Dictionary.
They detect light touch: Ackerman, Natural History of the Senses, 83.
if you sink a spade into gravel or sand: Linden, Touch, 46.
Curiously, we don’t have any receptors for wetness: “The Magic of Touch,” The Uncommon Senses, BBC Radio 4, March 27, 2017.
Women are much better than men at tactile sensitivity: Linden, Touch, 73.
skin gets its color from a variety of pigments: Jablonski interview.
Its production slows dramatically as we age: Challoner, Cell, 170.
“Melanin is a superb natural sunscreen”: Jablonski interview.
Melanin often responds to sunlight: Jablonski, Living Color, 14.
The red of sunburn: Jablonski, Skin, 17.
The formal name for sunburn is erythema: Smith, Body, 410.
The process is known as melasma: Jablonski, Skin, 90.
some 50 percent of people globally: Journal of Pharmacology and Pharmacotherapeutics, April/June 2012; New Scientist, Aug. 9, 2014, 34–37.
As people evolved lighter skin: University College London press release, “Natural Selection Has Altered the Appearance of Europeans over the Past 5000 Years,” March 11, 2014.
Skin color has been changing: Jablonski, Living Color, 24.
Indigenous populations in South America: Jablonski, Skin, 91.
Rather harder to explain have been the KhoeSan people: “Rapid Evolution of a Skin-Lightening Allele in Southern African KhoeSan,” Proceedings of the National Academy of Sciences, Dec. 26, 2018.
Using DNA analysis: “First Modern Britons Had ‘Dark to Black’ Skin,” Guardian, Feb. 7, 2018.
suggested that the DNA used in the analysis: New Scientist, March 3, 2018, 12.
We are actually as hairy as our cousins the apes: Jablonski, Skin, 19.
Altogether we are estimated to have five million hairs: Linden, Touch, 216.
it provides warmth, cushioning, and camouflage: “The Naked Truth,” Scientific American, Feb. 2010.
In furry mammals, it adds a useful layer: Ashcroft, Life at the Extremes, 157.
Horripilation also makes mammalian hair stand up: Baylor University Medical Center Proceedings, July 2012, 305.
genetic studies that dark pigmentation: “Why Are Humans So Hairy?,” New Scientist, Oct. 17, 2017.
“because it increases the thickness of the space”: Jablonski interview.
humans don’t seem to have pheromones: “Do Human Pheromones Actually Exist?,” Science News, March 7, 2017.