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instantly collapsed in tumult。 a lady brewster fainted。 robertfitzroy； darwin’s panion on the beagle twenty…five years before； wandered through thehall with a bible held aloft； shouting； “the book； the book。” （he was at the conference topresent a paper on storms in his capacity as head of the newly created meteorologicaldepartment。） interestingly； each side afterward claimed to have routed the other。
darwin did eventually make his belief in our kinship with the apes explicit in the descentof man in 1871。 the conclusion was a bold one since nothing in the fossil record supportedsuch a notion。 the only known early human remains of that time were the famous neandertalbones from germany and a few uncertain fragments of jawbones； and many respectedauthorities refused to believe even in their antiquity。 the descent of man was altogether amore controversial book； but by the time of its appearance the world had grown less excitableand its arguments caused much less of a stir。
for the most part； however； darwin passed his twilight years with other projects； most ofwhich touched only tangentially on questions of natural selection。 he spent amazingly longperiods picking through bird droppings； scrutinizing the contents in an attempt to understandhow seeds spread between continents； and spent years more studying the behavior of worms。
one of his experiments was to play the piano to them； not to amuse them but to study theeffects on them of sound and vibration。 he was the first to realize how vitally importantworms are to soil fertility。 “it may be doubted whether there are many other animals whichhave played so important a part in the history of the world；” he wrote in his masterwork on thesubject； the formation of vegetable mould through the action of worms （1881）； which wasactually more popular thanon the origin of species had ever been。 among his other bookswere on the various contrivances by which british and foreign orchids are fertilised byinsects （1862）； expressions of the emotions in man and animals （1872）； which sold almost5；300 copies on its first day； the effects of cross and self fertilization in the vegetablekingdom （1876）—a subject that came improbably close to mendel’s own work； withoutattaining anything like the same insights—and his last book； the power of movement inplants。 finally； but not least； he devoted much effort to studying the consequences ofinbreeding—a matter of private interest to him。 having married his own cousin； darwinglumly suspected that certain physical and mental frailties among his children arose from alack of diversity in his family tree。
darwin was often honored in his lifetime； but never for on the origin of species ordescentof man。 when the royal society bestowed on him the prestigious copley medal it was for hisgeology； zoology； and botany； not evolutionary theories； and the linnaean society wassimilarly pleased to honor darwin without embracing his radical notions。 he was neverknighted； though he was buried in westminster abbey—next to newton。 he died at down inapril 1882。 mendel died two years later。
darwin’s theory didn’t really gain widespread acceptance until the 1930s and 1940s； withthe advance of a refined theory called； with a certain hauteur； the modern synthesis；bining darwin’s ideas with those of mendel and others。 for mendel； appreciation wasalso posthumous； though it came somewhat sooner。 in 1900； three scientists workingseparately in europe rediscovered mendel’s work more or less simultaneously。 it was onlybecause one of them； a dutchman named hugo de vries； seemed set to claim mendel’sinsights as his own that a rival made it noisily clear that the credit really lay with the forgottenmonk。
the world was almost ready； but not quite； to begin to understand how we got here—howwe made each other。 it is fairly amazing to reflect that at the beginning of the twentiethcentury； and for some years beyond； the best scientific minds in the world couldn’t actuallytell you where babies came from。
and these； you may recall； were men who thought science was nearly at an end。
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26THE STUFF OF LIFE
小？说网
if your two parents hadn’t bonded just when they did—possibly to the second； possiblyto the nanosecond—you wouldn’t be here。 and if their parents hadn’t bonded in a preciselytimely manner； you wouldn’t be here either。 and if their parents hadn’t done likewise； andtheir parents before them； and so on； obviously and indefinitely； you wouldn’t be here。
push backwards through time and these ancestral debts begin to add up。 go back just eightgenerations to about the time that charles darwin and abraham lincoln were born； andalready there are over 250 people on whose timely couplings your existence depends。
continue further； to the time of shakespeare and the mayflower pilgrims； and you have nofewer than 16；384 ancestors earnestly exchanging genetic material in a way that would；eventually and miraculously； result in you。
at twenty generations ago； the number of people procreating on your behalf has risen to1；048；576。 five generations before that； and there are no fewer than 33；554；432 men andwomen on whose devoted couplings your existence depends。 by thirty generations ago； yourtotal number of forebears—remember； these aren’t cousins and aunts and other incidentalrelatives； but only parents and parents of parents in a line leading ineluctably to you—is overone billion （1；073；741；824； to be precise）。 if you go back sixty…four generations； to the time ofthe romans； the number of people on whose cooperative efforts your eventual existencedepends has risen to approximately 1；000；000；000；000；000；000； which is several thousandtimes the total number of people who have ever lived。
clearly something has gone wrong with our math here。 the answer； it may interest you tolearn； is that your line is not pure。 you couldn’t be here without a little incest—actually quitea lot of incest—albeit at a genetically discreet remove。 with so many millions of ancestors inyour background； there will have been many occasions when a relative from your mother’sside of the family procreated with some distant cousin from your father’s side of the ledger。 infact； if you are in a partnership now with someone from your own race and country； thechances are excellent that you are at some level related。 indeed； if you look around you on abus or in a park or café or any crowded place； most of the people you see are very probablyrelatives。 when someone boasts to you that he is descended from william the conqueror orthe mayflower pilgrims； you should answer at once： “me； too！” in the most literal andfundamental sense we are all family。
we are also uncannily alike。 pare your genes with any other human being’s and onaverage they will be about 99。9 percent the same。 that is what makes us a species。 the tinydifferences in that remaining 0。1 percent—“roughly one nucleotide base in every thousand；”
to quote the british geneticist and recent nobel laureate john sulston—are what endow uswith our individuality。 much has been made in recent years of the unraveling of the human genome。 in fact； there is no such thing as “the” human genome。 every human genom