DNA-lab “Prenatal research in plants”

Take a DNA-fingerprint from potatoes and find out if your plant has the right properties.

The genetic code of each individual is unique, with the exception of identical twins. The genetic differences between individuals, whether humans, animals or plants, can be exploited in a variety of ways. For thousands of years, we have been doing so with the breeding of animals or the improvement of plants. Nowadays for example we also use genetic differences to track down criminals, to check if a batch of corn has been genetically modified or to determine if a foetus has a genetic defect.

Techniques

In this DNA-lab the students are introduced to techniques that allow us to quickly determine whether a genetic property is inherited. In other words, Mendel’s laws at the level of DNA. In the practical, the topic polymerase chain reaction (PCR, the copying of DNA), enzyme action and cell construction are explored. The students will learn that the knowledge they possess on individual topics is mutually connected.

During the practical, DNA will be isolated and prepared for a PCR reaction. The product will be analysed using a DNA-gel (gel electrophoresis) and the students will work out the results by applying Mendel’s laws. During the PCR reaction the relationship between genotype and phenotype will be discussed. The students will analyse a number of genotypes and phenotypes and link the data to the results of the DNA-gel.

Potato

The experiments will be performed using potato seedlings. The use of human material raises ethical questions and this aspect will also be discussed in this DNA-lab. DNA-research on plant material offers many advantages over using animal or human material. But how far can we go?

Required knowledge

It is advisable that the students are familiar with certain concepts beforehand.

Organism level
• The student should be familiar with Mendel’s laws of heredity, including the concepts genotype, phenotype, gene, allele, dominant, recessive, X-chromosomal and autosomal.
• The student should be capable of drawing up monohybrid cross-fertilisation schemes and using these to predict the possible offspring and the corresponding ratio.

Cellular level
• The student is familiar with the subcellular structure of eukaryotic cells, in particular the function and construction of the cell nucleus and the cell membrane.
• The student understands the differences between a plant cell and an animal cell.

Molecular level
• The student should know the function of DNA, genes and chromosomes and how these are constructed.
• The student should be aware that hereditary properties are stored in the DNA and that the genes on the DNA code for proteins that can be produced by the cell.
• Gel electrophoresis and the polymerase chain reaction are applied. If the students already have some knowledge on these techniques, the practical can be used to explore these in more detail. When this is not the case, the techniques need to be discussed during the preparatory lesson to ensure that the students can understand this DNA-lab.

This DNA-lab can be used in biology lessons.