Essential Genetics 6th Edition by Daniel Hartl

Exercise 20

Six bands in a salivary gland chromosome of Drosophila are shown in the accompanying figure, along with the extent of five deletions (Del1-Del5).

Recessive alleles a , b , c , d , e , and f are known to be in the region, but their order is unknown. When the deletions are heterozygous with each allele, the following results are obtained:

In this table, the minus sign means that the deletion is missing the corresponding wildtype allele (that is, the deletion uncovers the
recessive allele), and the plus sign means that the corresponding wildtype allele is still present. Use these data to infer the position of each gene relative to the salivary gland chromosome bands.