Webinar on strawberry DNA extraction

Dr Ong (top row, middle) with the participants 

As part of the programme Minggu Sains Negara 2021, KLESF STEM Webinar titled "Could you see the DNA of living things?" was conducted on 3 April 2021 via Zoom and KLESF Facebook Live. The objectives of the webinar were to explore the simple method of extracting DNA from a strawberry and to learn the basic principle of DNA extraction. 

The webinar was delivered by Centre for Foundation Studies (CSF) Department of Science and Engineering Senior Lecturer Dr Ong Kiah Ju. In her talk, she first shared the significant contributions of scientists, namely Rosalind Franklin, James Watson and Francis Crick on the discovery of the double-helix structure of DNA. “DNA (Deoxyribonucleic Acid) is a type of nucleic acid and it is inherited from the parents,” she said. She stated that DNA is made of nucleotides which consist of three parts—phosphate, 5c sugar and four types of nitrogen bases, where the four bases are thymine, adenine, cytosine and guanine. 

She then presented how to extract DNA from a strawberry with the use of apparatus and materials which included detergent, glass, 70% ethanol, strawberry, salt, measuring cup, zip lock bag, stick and ice cubes. She presented how to prepare a DNA extraction buffer and shared the procedure to extract strawberry DNA step by step. “Besides using strawberries, you may use other fruits as well. The same applies for vegetables,” she said.

Dr Ong explaining the structure of DNA

Dr Ong presenting how to prepare the DNA extraction buffer

Dr Ong showing the steps to extract DNA from strawberries

Besides, she shared the precautions that need to be taken during the process. “You have to make sure the zip-lock bag is tightly sealed. Do not crush the strawberry for too long. It is also important for you to make sure the pulp is removed and make sure the ethanol is ice-cold,” she said. She also mentioned that it was possible to extract human DNA from cheek cells, and explained how this differs from extracting fruits’ DNA.

Dr Ong sharing the procedure of extracting human DNA

Moreover, she explained the principle behind the procedures and said, “A strawberry is a plant cell. A plant cell consists of a cell wall. The DNA is found inside the nucleus. In order to expose the DNA or nucleus to the environment, first of all, you need to break the cell wall so that the nucleus can be released to the environment. This is the purpose of crushing the strawberry.” She advised the participants to crush the strawberry thoroughly for two minutes instead of 10 minutes to avoid activating DNases that could destroy the DNA. She also further explained the function of using detergent, salt and Ice cold ethanol in the process of extracting DNA from the strawberries.  

She also talked about the similarities and differences between plant and animal DNA. “The DNA structures are still the same. The only differences are the arrangement, the sequence, and the number of bases which makes each of us unique,” she said. She also explained what will happen to the DNA after consuming them and shared some factors that will affect the amount of DNA collected. The talk then ended with a Q&A session and a group photography session.