|Adam’s Curse: A Future without Men |
by Bryan Sykes
Posted: September 3, 2004
In his previous book, The Seven Daughters of Eve, Sykes wrote about tracing human heritage by studying the DNA of mitochondria, which is inherited through the mother. The new book looks at the paternal side of life: the Y-chromosome, its origins, its power to resolve ancestral questions, and the prospects for the future.
Along the way, we join a fast-moving journey through the Viking conquests, the dissemination of a lineage left by Genghis Khan, his sons and grandsons, and the perilous future of the genetically mangled Y-chromosome.
The title comes from the author’s view that the modern Y chromosome is cluttered with junk and a dearth of useful genes, all contributing to a rather high incidence of human male infertility (about 7 percent).
Sykes, a professor of genetics at the Institute of Molecular Medicine at Oxford University, the United Kingdom, even posits that the Y chromosome is disintegrating, and he estimates that the human male’s Armageddon will be 125,000 year from now!
Despite continual nods to the handiwork of natural selection, he seems to ignore its power to repair the Y chromosome ills in his future. I wonder how the 4,500 odd species of mammals living today seem to reproduce so well with their feeble Y chromosomes?
Sykes begins with a detailed reverie wondering about his possible family relationship to Sir Richard Sykes, chairman and CEO of Glaxo Welcome, and goes on the discover that the pharmaceutical chief’s Y-chromosome profile matches his own, along with those of half the boys from Yorkshire.
The author cautions: “I know from bitter experience that, although there is nothing more fascinating than your own family history, there is nothing more tedious than someone else’s.”
Unfortunately this disclaimer doesn’t lead him to restrain from telling us tell the backgrounds, in considerable detail, of the Sykes, Sike, and Sikes. The only glaring omission to this reader would be a genotypic connection to the murderous scoundrel Bill Sykes of Oliver Twist.
Adam’s Curse devotes three chapters to applaud and expound the theories of evolutionary ecologist William Hamilton to explain the survival, dispersal, and chaotic journeys of the Y-chromosome. To me Sykes’ arguments become a bit speculative given some of the quotes he includes from Hamilton.
We also get a discussion about the search for genetic influence on sexual orientation and a fanciful hypothesis about why a gene might influence 5 to 10 percent of the population to prefer homosexual relationships. Sykes reasons that the gay gene, if it exists at all, may somehow be advantageous to females, but this too is speculative.
Even so, there is much to like in Adam’s Curse, and Sykes is a good storyteller. He is at home with his own role in solving the migration of Polynesians as in detailing MIT biologist David Page’s discoveries last year that a total of eight palindromes—gene sequences that are mirror images—comprise the functional part of the Y chromosome. These findings helped to explain why the Y is so extraordinarily difficult to map.
In places I wondered whether Sykes’ intended audience is college sophomores, or educated lay people who watch NOVA and read Scientific American, or professional scientists. Sykes is an engaging thinker, teacher, and a talented writer. Yet, it is difficult to reach all levels at once, and mixing the targets sometimes can be a distraction.
Adam’s Curse offers well written, provocative, and fast-moving anecdotes, and the storytellers of science—particularly narrators of the genome script—need to be encouraged. The scientific community has been presented with a precious gift, the gene record for millions of evolutionary experiments that led to humankind’s survival, while many, many more species have perished.
To crack that timeless genomics crypt holds promise for mankind and for the earth’s well-being. If we are to learn from the lessons of genomic history, then perhaps we can avoid the repetition of a few missteps by our ancestors of long ago.
Stephen J. O'Brien is Chief of the Laboratory of Genomic Diversity at the National Cancer Institute in Bethesda, Maryland, and author of Tears of the Cheetah and Other Tales from the Genetic Frontier.