Some questions about the map file

[bernicegu]

Thank you very much for providing this software; it has been very helpful to me. However, I have some questions and look forward to your response.

My project does not have QTL mapping data, only SNP loci, and I want to infer the genotypes of the offspring. Is this map file necessary? What is its significance? Can I replace it with the SNP positions on the chromosomes?
Thank s