Biology, Eighth Edition (Raven)

Chapter 18: Genomics

FISH

What is the purpose of the FISH technique? FISH is a technique for mapping the location of genes onto chromosomes. The FISH map is a physical map, it shows the physical location of a gene on a chromosome. Genes can also be mapped using the frequency of recombination during meiosis. A recombination map calculates map distances between pairs of genes. Gene sequencing can also produce maps of genes that show not only their location but also the structure of the genes themselves. An advantage of the FISH technique is that it does not require information about other genes to map a single gene. All that is needed is a labeled probe that will bind to the gene.

View the animation below, then complete the quiz to test your knowledge of the concept.


1.	The term in situ is ________ for ________ .

		A)	Greek ; in cell
		B)	Greek ; in place
		C)	Greek ; in lab
		D)	Latin ; in cell
		E)	Latin ; in place

2.	The cells used in the FISH technique are first arrested during

		A)	interphase.
		B)	metaphase.
		C)	telophase.
		D)	prophase.
		E)	anaphase.

3.	Arrange the following in the proper sequence in which they occur during FISH. 1. Denaturation of DNA 2. Addition of DNA probes 3. Fixation of chromosomes

		A)	1, 2, 3
		B)	2, 1, 3
		C)	2, 3, 1
		D)	3, 2, 1
		E)	3, 1, 2

4.	In situ hybridization is used to detect the physical location of a gene on a chromosome.

		A)	True
		B)	False

5.	FISH probes are fluorescently-labeled and designed to bind only to non-complementary DNA.

		A)	True
		B)	False