At 09:59 AM 4/30/2007 -0700, you wrote: >[EMAIL PROTECTED] wrote: >> Ok, after seeing some of the comments made thus far - the question I have >> is, were my numbers more or less on the money, and if so, does it make for >> a reasonable explanation? > >No, your numbers were not on the money. You're making the assumption >that there's a 50% chance of having each of the specific genes, and the >real chance can range anywhere from 0 to 100%, depending mostly on >evolutionary advantage. > >If you want to have a constant low rate of a trait, it implies that >either the trait is not significantly evolutionarily favored (seems >unlikely for magery) or that the trait is one which results in >evolutionary disadvantages if it becomes too prevalent in the breeding >pool (e.g. the gene for sickle-cell anemia gives resistance to malaria >if you have one copy, but is likely to kill you if you have two copies). > >A dominant gene that produces negative effects if it occurs twice is >pretty easy to recognize, however, and would just mean that mages always >breed with non-mages. Some combination of multiple genes is probably >more reasonable.
Ok, in saying I was off the mark, you made me re-evaluate what my assumptions where rather than plot them out. A simple Dominant/Recessive trait scheme would result in the following mendel square: Mother: DD Mother: dD Mother: Dd MOther: dd Father: DD Father: Dd Father: dD Father: dd The odds of having the traits required where the child born has both dd is actually 1 in 4, rather than 1 in 2. I used the reciprocal of 2^n where n = number of gene sites required to produce a magery of a given level. The actual odds of achieving a given trait where both are recessive depends on both parents giving the child the recessive gene. When you increase the number of gene sites to 2, the odds of a child getting recessives at both sites becomes 1 in 16. Which means, that instead of the formula being the reciprocal of 2^N where N = number of genes involved, it looks like I should have used the reciprocal of 4^N where N = number of sites. Can anyone confirm? _______________________________________________ GurpsNet-L mailing list <[email protected]> http://mail.sjgames.com/mailman/listinfo/gurpsnet-l
