If you truncate less of the tail, it takes more generations to move the mean, but I believe that by the time it moves the same distance, the variance shrinks less.
If you have a randomly mating population, apply assortative mating for a few generations, apply one generation of selection, and let randomly mix, it costs less variance for the same mean as if you don’t do assortative mating. That’s because assortative mating is a kind of selection, so this is like several generations of selection. If you start and end with an equilibrium of assortative mating, I’m not sure what happens. Also, assortative mating increases the variance, so you have to distinguish between the variance of the population and the variance of the population that would result if you switched to random mating.
If you truncate less of the tail, it takes more generations to move the mean, but I believe that by the time it moves the same distance, the variance shrinks less.
If you have a randomly mating population, apply assortative mating for a few generations, apply one generation of selection, and let randomly mix, it costs less variance for the same mean as if you don’t do assortative mating. That’s because assortative mating is a kind of selection, so this is like several generations of selection. If you start and end with an equilibrium of assortative mating, I’m not sure what happens. Also, assortative mating increases the variance, so you have to distinguish between the variance of the population and the variance of the population that would result if you switched to random mating.