It is understandable that my ethos is not on par with Dr. Walker's, and that my anecdote would indeed make me an outlier. With that being said, I am legitimate

It is understandable that my ethos is not on par with Dr. Walker's, and that my anecdote would indeed make me an outlier. With that being said, I am legitimately unable to find any conclusive research that says there are effectively three "cronotype" bands, and 100% of the population falls into one of these three bands, and that these bands are completely DNA-driven and non-dynamic. Every source of this information seems to be behind a "buy my book" paywall from some inspirational speaker like Daniel Pink. The article says: "For further proof, researchers at Rockefeller University last year announced the discovery of a gene mutation that apparently accounts for D.S.P.S." In that study, the author says, " According to the new research, the mutation may be present in as many as one in 75 people in some populations." While there might be more genes which lend themselves to DSPS, the numbers from the study don't exactly lend extra credibility to the argument. Can you help me to understand where it has been statistically proven that 100% of humans fall into roughly three equal bands of morning/evening/between, and that this has been solidly linked to genetics rather than environmental/habits or a combination of both? Most studies on humans don't make such bold claims because genetics are so diverse across populations that the study population itself would need to be enormous.