Extraction of DNA From Onion


To isolate DNA from onions

Extraction of DNA From Onion Theory

DNA is the genetic material of all living organisms. Within this master molecule, all the information necessary to create and direct the chemical machinery of life is found. Before being able to study DNA in the context of a university research laboratory, medical analyses, or criminal investigations, scientists must be able to extract it from the tissue in which it is contained.

Materials and apparatus used

  1. Mortar and pestle
  2. Two pieces of onion
  3. 250 ml and 500 ml of beakers
  4. 100 ml of measuring cylinder
  5. Ice bath
  6. Glass rod
  7. Spatula
  8. Heating mantle
  9. Funnel and tripod stand
  10. Filter paper
  11. Glass Petri dish
  12. Distilled water
  13. Ethanol (95%)
  14. Soap solution (liquid soap)
  15. Table salt

Extraction of DNA From Onion Procedure

Extraction of DNA From Onion
Extraction of DNA From Onion
  1. Blend or grind the onion into pieces by using mortar and pestle, transfer into a beaker using a spatula or spoon.
  2. In another beaker add 4 to 5 spatulas of salt to the liquid soap.
  3. Add 40 to 50 ml of water to solubilize salt and soap (stir with a glass rod).
  4. Add the above solution to the chopped onion in a beaker and stir with the glass rod.
  5. Heat the mixture at 50ºC for 5-7 minutes in a heating mantle and stir continuously with a glass rod.
  6. Cool the mixture and filter it and collect the filtrate in a beaker.
  7. Take 20-30 ml of ethanol (95%) in a Petri dish.
  8. Keep it on an ice tray or ice water bath for cooling.
  9. After few minutes slowly pour the filtrate on the Petri dish.
  10. After a few minutes, there is the formation of the white small granular frame or network-like structure  DNA. (white ppt)


The DNA was isolated from the onion.

Make sure you also check our other amazing Article on : Column Chromatography
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