He forcefully argues that no single known gene is sufficient to ensure athletic success

From Talent Lies Within. But Where? by Christie Aschwanden.

But what exactly differentiated the two runners? Was Scott endowed with some gene for speed? Could David’s grit and determination overcome his apparent lack of innate ability? Where does the intersection between talent and practice lie?

These are the questions Mr. Epstein seeks to answer in this captivating book, which began as a feature in Sports Illustrated, where he is a senior writer. The book’s title misleads, since he forcefully argues that no single known gene is sufficient to ensure athletic success. His answer to the question “Nature or nurture?” is both.

If that sounds like a hedge, it isn’t: instead, it’s a testament to the author’s close attention to nuance. He approaches his subject like a scientist, stopping to examine the uncertainties and taking care not to overgeneralize.

[snip]

Whether (and how fast) chumps can become champs depends on their baseline ability and how rapidly they improve — factors highly influenced by genetics. After months of identical training, some exercisers make almost no fitness gains, while others increase their aerobic capacities by 50 percent or more. Scientists have identified more than 20 gene variants that can separate high responders from low ones.

Mr. Epstein argues that we often confuse innate talent with spirit or effort. Even traits like desire may arise from DNA (see the Iditarod dogs selectively bred for enthusiastic pulling), but that does not mean they come down to any single gene. Whether it’s running faster, standing taller or jumping higher, multiple genetic pathways may lead there.

In a particularly fascinating chapter, Mr. Epstein investigates an old theory that purports to explain why one small country, Jamaica, produces so many Olympic sprinters. The notion is that strong Africans were selected as slaves, that the strongest of them survived the voyage to Jamaica, and that the strongest survivors eventually escaped slavery and cloistered themselves in a remote region to form an isolated “warrior” gene stock that now produces world-class athletes.

It makes a convenient story. But it is belied by the DNA research of Yannis Pitsiladis, a biologist at the University of Glasgow, who finds no genetically distinct subgroup of Jamaican sprinters. It appears that Jamaica churns out sprinters because almost everyone on the island tries the sport.