Question

question 1
sarah, a molecular biologist, is a proud parent of two beagle puppies. after a day at work, sarah arrived home to find her favorite pair of shoes with chew holes from dog teeth. apply your knowledge of dna extraction, amplification, and analysis to describe how sarah could use her lab bench to determine which of her puppies destroyed her shoes.

Explanation:

1. DNA Extraction:

• Sarah would first extract DNA from the saliva in the chew holes of the shoes. This can be done using standard DNA extraction kits that lyse cells (if there are any cells from the puppy's mouth in the saliva) and isolate the DNA.

1. DNA Amplification (PCR):

• She would then use Polymerase Chain Reaction (PCR). Primers specific to dog DNA sequences (e.g., microsatellite regions or other polymorphic regions in the dog genome) would be used. The PCR would amplify the DNA from the saliva sample.

1. DNA Analysis (e.g., Gel Electrophoresis or DNA Sequencing):

• For gel electrophoresis: The amplified DNA from the shoe - saliva sample would be run on a gel. DNA samples from each of the two puppies would also be extracted, amplified (using the same primers), and run on the same gel. By comparing the banding patterns (if using a method like microsatellite analysis where different alleles show as different band positions), she could see which puppy's DNA pattern matches the DNA from the shoe.
• For DNA sequencing: The amplified DNA regions could be sequenced. The sequence from the shoe - saliva DNA would be compared to the sequences from each puppy. A match in the sequence (especially in polymorphic regions) would indicate which puppy was responsible.

Answer:

Sarah could extract DNA from the saliva in the shoe's chew holes, amplify it using PCR with dog - specific primers, and then analyze it (either by gel electrophoresis comparing banding patterns or by DNA sequencing and sequence comparison) with DNA from each puppy to determine which puppy destroyed the shoes.