In pillbugs, sex is determined by two chromosomes: Z and W. Individuals who inherit two Zs develop as males, while ZW individuals become female. But in some populations, these rules are overwritten by a microbe called Wolbachia.
Wolbachia infects the cells of pillbugs and only passes down the female line; only mothers can transmit the bacterium to their young. Male embryos are dead ends to Wolbachia, so when it runs into them, it feminizes them by interfering with the development of hormone-producing glands. The result is that all young pillbugs infected with Wolbachia grow up into females, even those that are genetically male. In such populations, the W chromosome tends to disappear altogether. Eventually, all the pillbugs are ZZ, and it’s the presence or absence of Wolbachia that dictates whether they become female or male. . . . In the 1980s, the French researchers showed that some pillbugs do not have Wolbachia, but act as if they did. They’re all ZZ, but some still develop as females. The researchers proposed that the bacterium has transferred a piece of its DNA into the pillbug’s genome, and that this “feminizing element”—or f-element—was now dictating the animal’s sexes, even in the microbe’s absence.
From The Atlantic Magazine.
What if a bacterium, with a similar effect on humans to Wolbachia in pillbugs (i.e. initially turning males into females until Y-chromosomes disappear and then eventually adding its own sex determination gene), rapidly spread through our world in the early 21st century?
This occurs because the bacterium infects the leading, internationally distributed bottled water brand, staring in the year 2014 and infects 80% of all people who every drink and bottled water in the time period from the year 2014 to the year 2029.
The source of the bacterium is not discovered until fifteen years after the bacterium had initially started to spread, because of a clerical error in processing the data that addresses possible causes early on, that is published in a prestigious scientific journal. This error is not be caught by anyone early on. The data published in the journal appears to rule out the bacterium that is responsible as a cause, sending scientists looking for the cause on a wild goose chase for another cause.
Assume that the bacterium is an otherwise symbiotically helpful gut bacterium.
How would the world react and change as a result?