‘I would still be loath to call it “evolved to death”. Where is the “evolution”?’
It happens because of a change in gene frequencies. That’s what evolution is defined as—changes in gene frequency. The mutant allele spreads and takes over. The population dies, but that doesn’t keep the mutant allele from taking over among survivors while there are survivors.
Someone said the mutant allele isn’t competing with X chromosomes. It’s competing with both X and Y alleles. The mice start out with on average 3 X alleles per Y allele. At the end it’s 1 X allele per mutant Y allele.
‘Too bad, so sad. If there was an “evolution fairy”, she would have designed a better machinery of genes.’
There may be a better machinery sometimes. The examples we have of segregation distorters may be examples where the better mechanism has broken down.
In the absence of better mechanisms, this sort of thing can happen. It’s possible to get mutations which are selected and which spread even though in the long run they are bad for the population as a whole.
Analogously it’s possible to make a lot of money in a free enterprise system while benefitting nobody but yourself, barring mechanisms to prevent that—the “invisible hand” doesn’t necessarily work to do what Adam Smith said it can do.
‘I would still be loath to call it “evolved to death”. Where is the “evolution”?’
It happens because of a change in gene frequencies. That’s what evolution is defined as—changes in gene frequency. The mutant allele spreads and takes over. The population dies, but that doesn’t keep the mutant allele from taking over among survivors while there are survivors.
Someone said the mutant allele isn’t competing with X chromosomes. It’s competing with both X and Y alleles. The mice start out with on average 3 X alleles per Y allele. At the end it’s 1 X allele per mutant Y allele.
‘Too bad, so sad. If there was an “evolution fairy”, she would have designed a better machinery of genes.’
There may be a better machinery sometimes. The examples we have of segregation distorters may be examples where the better mechanism has broken down.
In the absence of better mechanisms, this sort of thing can happen. It’s possible to get mutations which are selected and which spread even though in the long run they are bad for the population as a whole.
Analogously it’s possible to make a lot of money in a free enterprise system while benefitting nobody but yourself, barring mechanisms to prevent that—the “invisible hand” doesn’t necessarily work to do what Adam Smith said it can do.