It began in Ethiopia, hundreds of thousands of years ago. When a handful of genetic mutations caused evolution to split from the primates. And mankind was born. Now, eons later, evidence of more splits from the apes are being unearthed. And with them, a disturbing realization. Ours was only one of many. And yet we survived. But it was not by luck or chance. We survived because humans had something the others did not. A unique ingredient that has only...