From Abby Olena at the Scientist:
For more than 50 years, scientists have taken for granted that all snakes share a ZW sex determination system, in which males have two Z chromosomes and females have one Z and one W. But a study, published today (July 6) in Current Biology, reveals that the Central American boa (Boa imperator) and the Burmese python (Python bivittatus) use an XY sex determination system, which evolved independently in the two species.
If a f fundamental change like that could evolve independently, something other than Darwin’s nature “hourly adding up” must be at work. But what? An internalized library of possible solutions, as Lee Spetner suggests?
Gamble agrees that the next step is exploring other species’ sex chromosome systems, but, for him, a bigger question also arises from this work. “There’s way more going on in snakes than anyone ever thought,” he says. “It was there for anyone to see, and so many scientists—including myself—failed to really look critically at this older literature. One has to wonder how frequently we do this. What other long-held assumptions do I take for granted as factual that could actually not have any empirical evidence behind them?”More.
The empirical evidence they have behind them is the failed and stunted careers of the people who opposed some dogma in conflict with evidence that is a money-spinner for conventional profs.
Yes. That’s it. That’s what empirical evidence many dogmas have got behind them.
When we turn science into religion or politics, we tend to miss the science part: Smart people can be wrong on the evidence.
See also: Convergent evolution: When snakes crowdsource
Harmless snakes mimic an extinct poisonous snake (Seems no one told them Fang was dead.)