What is Turbidity?

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Turbidity is basically how cloudy a liquid is. For example, vodka has a low turbidity, but milk has a high turbidity.

For our goal of genotyping salmon, we decided to use LAMP (loop-mediated isothermal amplification) because of its ability to give a cheap and easy binary result (yes, it’s coho, or no, it isn’t coho).

[This method uses a DNA polymerase with strand displacement activity and yields large quantities of DNA in less than an hour under constant temperature (thus obviating the need for expensive thermocyclers). Moreover, a correspondingly large amount of white magnesium pyrophosphate precipitate is synthesized as a by-product, enabling direct visual confirmation of amplification success through monitoring of mixture turbidity. These characteristics provide results in a fast, efficient, and cost-effective method that theoretically should amplify target sequences with higher specificity than PCR.] –¬†https://www.nature.com/articles/srep40125

From the papers we reviewed, we learned that a positive LAMP amplification would result in the production and precipitation of magnesium pyrophosphate (Mg2P2O7). We’ve been designing based on the idea that we would be able to see the change in turbidity during a positive control. Unfortunately, we learned later that the change in turbidity would not be visual to the naked eye (change in turbidity would be around 0.7 NTU….basically invisible).