Question

You have identified a partial genomic sequence for a gene in mouse and would like to use fluorescent in situ hybridization (FISH) to study this gene. Below is a partial DNA sequence (coding/nontemplate strand). The DNA sequence that corresponds to intron 1 is underlined.

5'...Exon 1...AGCTTGGGAGCGGCGGTGAGGCGGGAGGCG...Intron 1...TCCTCTCTCCCCCAGGGCCCACCAGCTCTG...Exon 2...3'

Use this sequence to answer the following questions.

First, you would like to use FISH to confirm the position of the gene on chromosome 7 as well as the location of this part of the chromosome in an interphase nucleus. You decide to design a probe to hybridize to the genomic DNA containing this gene.

Which of the following DNA probes could you use to detect this gene in mouse? Select all that apply.

O 5' TTGGGAGCGG 3'
O 3' AACCCTCGCC 5'
O 5' AACCCTCGCC 3'
O 3' TTGGGAGCGG 5'

Answer 1

The suitable DNA probes for detecting the gene in mouse using FISH are 5' TTGGGAGCGG 3' and 3' AACCCTCGCC 5', as they are complementary to the template strand corresponding to the given non-template DNA sequence of the gene.

Step-by-step explanation:

To utilize fluorescent in situ hybridization (FISH) for identifying the location of a specific gene on a chromosome, it is essential to design a DNA probe that is complementary to the sequence of interest. The DNA sequence provided represents the coding or non-template strand, so the probe must be complementary to the template strand that has the opposite sequence.

In this case, for the sequence 5'...AGCTTGGGAGCGGCGGTGAGGCGGGAGGCG...3', the complementary probes which can bind to the target sequence are 5' TTGGGAGCGG 3' and 3' AACCCTCGCC 5', since they are complementary and antiparallel to the given strand. It's important to note that the probe should not include intron sequences, as introns are non-coding and can vary between different cells, making it difficult to get a specific result. The final answer, therefore, is that the probes 5' TTGGGAGCGG 3' and 3' AACCCTCGCC 5' are suitable for detecting this gene in mouse.