During recombination (or "crossover") bases are exchanged between two homologous chromosomes. However, all material dealing with this talks about genetic distance, linkage, and in terms of the centimorgan unit. I realise that this average probability has to take into account the length of the chromosome. However, I have been unable to find the answer. I think that it might not be a meaningful question, but I also don't understand why it's not meaningful.