Final answer:
A physical map represents the physical distance between genes or genetic markers, providing details of the actual distance in nucleotides. Different methods like cytogenetic mapping, radiation hybrid mapping, and sequence mapping are used to create physical maps. Sequence mapping provides the most detailed information on physical distance by directly sequencing the genome.
Step-by-step explanation:
A physical map is a representation of the physical distance, in nucleotides, between genes or genetic markers. It provides detail of the actual physical distance between genetic markers, as well as the number of nucleotides. Physical maps are created using methods like cytogenetic mapping, radiation hybrid mapping, and sequence mapping. Cytogenetic mapping uses microscopic analysis of stained sections of the chromosome to determine approximate distances, while radiation hybrid mapping uses radiation to break DNA into fragments. Sequence mapping provides the most detailed information on physical distance by sequencing the genome.