Equations:

Probabitiy of i crossovers

Given genetic distance of m morgans (m=centimorgans/100)

p_co=function(m,i){ return(exp(-m)*m^i/factorial(i)) }

Proportion of heteromorphic dyads

Given a genetic distance of m morgans. sums over possible numbers of crossovers from 0 to (the very unlikely) 10.

h=function(m){ return(sum(sapply(0:10, function(i) return( 2/3*(1-(-0.5)^(i))*p_co(m,i) )))) }

% Drive given genetic distance m Morgans

d=function(m){ h(m/100)+(1-h(m/100))/2}

Plot % drive vs. cM distance

#Range of possible cM from 0 to 200
centimorgans<-0:2000/10

# % drive using equation above
drive_percent=sapply(0:2000/10,function(x) d(x))

plot(drive_percent~centimorgans,type="l")