Figure 19.17: With in situ hybridization, DNA probes are used to determine the cellular or chromosomal location of a gene or its product. (a) A probe with green fluorescence is specific to chromosome 7, revealing a deletion on one copy of chromosome 7. (b) In situ hybridization is used to detect the presence of mRNA from the tailless gene in a Drosophila embryo.
[Part a: Addenbrookes Hospital/Science Source. Part b: Courtesy of L. Tsuda.]