Functions to convert recombination fractions to distance in cM (centiMorgans).
Usage
haldane(rcmb)
kosambi(rcmb)
Arguments
rcmb
A recombination fraction between two markers, i.e., a number between
0 and 0.5.
Value
Both functions return a number with a distance measured in cM.
Details
Haldane mapping function is defined as
$$d_{M} = -\frac{1}{2}\ln(1-2r),$$
for $0 \leq r \leq 0.5$, where r stands for the recombination fraction
in rcmb. Kosambi mapping function is
$$d_{M} = \frac{1}{4}\ln \left[ \frac{1+2r}{1-2r} \right],$$ for $0 \leq r \leq 0.5$, where
r is defined as above.
References
Haldane, J. B. S. (1919) The combination of linkage values and the
calculation of distance between the loci of linked
factors. Journal of Genetics 8: 299-309.
Kosambi, D. D. (1944) The estimation of map distance from
recombination values. Annuaire of Eugenetics 12: 172-175.
# little difference for small recombination fractions haldane(0.05)
kosambi(0.05)
# greater difference as recombination fraction increases haldane(0.35)
kosambi(0.35)