I got an answer key as "I-1 (granddad) has a single X chromosome and has a 13 kb band, I-2 (grandma) is homozygous with a 7 kb bands. Their daughter will be heterozygous and have 13 and 7 kb bands". Please explain how to get these numbers 5. A region of the X chromosome has three polymorphic XbaI sites. These differences are illustrated in the two maps below: Map#1 and Map#2. These two maps were found in the two grandparents shown in the pedigree. (The grandmother is homozygous for her chromosome.) Their daughter is therefore heterozygous for these three XbaI polymorphisms. a) The 5kb MboI fragment from this region was cloned from the grandmother's X chromosome and the plasmid is shown below the chromosome maps. Fill in the Southern blot with bands showing the expected fragment sizes using probe #1 for the XbaI digests of the grandparents and their daughter..