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A Shot of Worm April 14, 2010

Posted by zach in Biology, Genetics.

Have you ever seen a bottle of the Mexican liquor Mescal with a  caterpillar lying at the bottom and wondered why a worm is at the bottom of a bottle of alcohol?  A group of researchers at the Biodiversity Institute of Ontario had the same idea…but took it to the next level.

Did someone slip something into my drink?

The researchers looked to see if any DNA from the worm could have leaked into the alcohol.  To the researchers surprise the bottle of alcohol contained sections of nuclear DNA from the caterpillar.  When drinking Mescal with a worm at the bottom you may not be eating or drinking the worm but, you are still consuming some of the worms DNA.  Just something to think about the next time before you order a drink with a caterpillar lying at the bottom.

The worm in the bottom of a bottle of Mescal

Ethanol which is the active ingredient in an alcoholic beverage also has wide implications in genetic research.   Ethanol is commonly used as a solvent to store both samples of DNA and RNA because the samples can be frozen at extremely low temperatures and ethanol limits the formation of ice crystals which can denature the strands of DNA. From this it is not extremely surprising that the DNA from the worm is stable in liquor, which contains forty percent ethanol. It is still amazing that the DNA leaked out from the caterpillars cell’s nucleus and stayed relatively intact.

Does this taste funny to you?

The researchers took a sample of Mescal then removed all the liquid ethanol by evaporation to extract only the DNA.  Next they ran polymerase chain reactions to see if first the sample contained any DNA from the caterpillar.  This analysis found that the Mescal did contain sections of DNA that could be traced back to the worm. This sparked the researchers to see, if by using pure ethanol solvent and a sample free of any extraneous DNA, if they could extract a full genome from a sample. To the researchers surprise when they used this protocol they had success that was near perfect.  This shows that it is possible to extract DNA from a sample by less evasive techniques.  This opens up possibilities for DNA extraction where there is either too little of a sample for traditional extraction procedures or when the sample cannot be destroyed (chopped up and lysed).   With these techniques geneticist can extract DNA from samples that was not possible prior to this technique.

One more implication brought to light by this research may concern contamination. Commonly when sample are collected in the field they are placed in a jar full of ethanol to be preserved until they reach the laboratory.  If the samples are going to require genetic testing a greater level of care is now going to have to be taken to prevent contamination.

The full study is located at Bio Techniques


1. Dr. O - April 16, 2010

SO cool! This gives me ideas about next year’s labs!

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