To taste or not to taste, that is the question. In the PTC Taster Lab you will examine how small genetic variations called single nucleotide polymorphisms (SNPs) can change our ability to perceive the world around us. The human sense of taste is composed of an intricate neurophysiological network, but as we’ll see in this lab, it only takes a few small changes in our DNA to change the way we taste.
Alleles of the TAS2R38 taste receptor gene can confer the phenotypic ability to taste the chemical Phenylthiocarbamide (PTC) and other bitter flavors. You will PCR amplify your own TAS2R38 taste receptor gene and use DNA restriction analysis to determine whether you have taster or non-taster version of the gene. You can determine whether you are homozygous or heterozygous for this trait, and correlate your genotype with your own ability to taste PTC (and foods that contain related chemicals, such as broccoli).
This Learning Lab is aligned with National Standards and AP Biology objectives. It utilizes the following molecular genetic techniques:
- DNA extraction from cheek cells
- PCR amplification of human genomic DNA
- Restriction digest analysis of human SNPs
- DNA Gel electrophoresis, staining, and visualization
The miniPCR PTC Taster Lab kit contains reagents for 8 lab groups of 4 students each (32 students):
- X-TractTM DNA extraction buffer
- 2X EZ PCR Master Mix, Load-ReadyTM
- PTC Lab Primer Mix, 2X concentrate
- Restriction enzyme
- 100 bp DNA ladder
- These reagents require frozen storage.
- Microtubes and electrophoresis reagents sold separately.
Free miniPCR Learning LabTM downloads:
- PTC Taster Lab Instructor’s Guide
- PTC Taster Lab Student’s Guide
- PTC Lab Classroom Slides
- miniPCR Hardy-Weinberg Calculator
Contact team@ Southern Biological for answers key.