Morgan, M, is the length of a segment that produces on average 1 crossover \(E[\text{nº of crossovers in 1M}]=1 \)
It varies between species and chromosome regions. Under the assumption that r is constant across the chromosome we can use it to map genes in a chromosome and measure the chromosome size.
IMPORTANT: The recombination fraction is not additive: \(r_{AC} \neq r_{AB}+r_{BC}\). There is no lineal relation between \(r_{AC}\) and \(x_{AC}\). To translate from Morgan to base pairs we use map functions: Haldane Map Function and Kosambi Map Function.
In practice we estimate the recombination fraction and use a map function to convert it into base pairs.
\(\)