The Meiotic Drive.

In Richard Dawkins' The Selfish Gene he describes the Meiotic Drive.  This is when a mutant gene - called a segregation distorter - skews the meiosis cell division in its favour so that it is more likely to end up in the egg.  It happens in mice.  If a mouse has a single t gene, 95% of its sperm will contain this mutated gene and so virtually all of its offspring will carry it.  The gene will then spread, Dawkins says, 'like brushfire' through the population.  This has catastrophic results because although mice with a single t gene are fine, those that inevitably inherit two of these genes are not.  They die early and are sterile and so soon the population dies out.

Ever since I read about this t gene a couple of nights ago I keep thinking about the other 't genes': the inaccurate result that seems right; the misinterpreted piece of gossip that no one questions; the witness who sees what appears to be a crime but is really something quite innocent.  The plausible idea that turns out not to be.  All t genes, perhaps.  They are hidden from view.  So the genes spread and spread.  Outside, everything seems fine but it isn't.  And its only when the children start acquiring  both genes that the real story can be heard.  And then it's too late.