Which Drosophila individual must be hemizygous?

Question

Quizplus · Accepted Answer

Hemizygous means having only one copy of a gene instead of the usual two. This can only occur in males for X-linked loci because they only have one X chromosome. Females have two X chromosomes, so they would need to have homozygous or heterozygous alleles on both X chromosomes to be hemizygous for a particular allele. Males, on the other hand, only have one X chromosome and one Y chromosome, so they will only have one copy of any X-linked gene, making them hemizygous for that locus.

Which Drosophila Individual Must Be Hemizygous