Question

Suppose you performed a mutant screen in the plant Arabidopsis using a cloned and sequenced bacterial transposable element as a mutagen. You generated 1000 diploid plant lines, each homozygous for a chromosome in which the transposable element integrated into a random location. You screen the lines for plants that make no flowers, as your goal is to identify genes required for flower development. You find that 10 of your 1000 lines make no flowers. What is the easiest and best way to identify the mutant gene in each of your 10 lines?

A. Hundreds of Arabidopsis lines are available with mutations that cause morphological mutant phenotypes. Use these lines to perform positional cloning: In test crosses, determine linkage and recombination frequency (RF) between the mutations in each of the ten lines and each of these morphological markers.

B. Thousands of Arabidopsis lines are available, each of which contains a different chromosomal deletion. Use deletion mapping to determine the location of the mutant genes.

C. Prepare genomic DNA from each of the 10 lines, digest it with a restriction enzyme that cuts once in the transposable element, treat the DNA with ligase to circularize the restriction fragments, and use inverse PCR to determine the base pair sequences of the Arabidopsis genomic DNAs adjacent to the transposable element.

D. Transform each of the 10 lines with an Arabidopsis genomic library made in bacterial plasmids, screen for rescue of the flowerless mutant phenotype to wild-type, and then determine the base pair sequence of the Arabidopsis genomic DNA insert in the plasmid that rescues.

Answer 1

The easiest and best method to identify the mutant gene responsible for the lack of flower development in the Arabidopsis lines is option C, which uses inverse PCR to determine the insertion points of a transposable element in the plant genome. The correct answer is option c.

Step-by-step explanation:

The easiest and best way to identify the mutant gene in each of the 10 Arabidopsis lines that make no flowers is to use the transposable element as a tag to recover flanking plant DNA sequences. The appropriate method to achieve this is described as option C: Prepare genomic DNA from each of the 10 lines, digest it with a restriction enzyme that cuts once in the transposable element, treat the DNA with ligase to circularize the restriction fragments, and use inverse PCR to determine the base pair sequences of the Arabidopsis genomic DNAs adjacent to the transposable element.

This approach is efficient and precise, allowing researchers to quickly identify the insertion points of the transposable element and therefore the potential genes disrupted that may be involved in flower development.