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Mixing the DNA of different organisms for sequencing

By Ana Castillo-Páez, 15th February 2024

Recently, there have been many molecular tools that allow us to both sequence a large part of the genome per individual, as well as to mix DNA from different individuals to sequence them in a single run.

In the laboratory, after extracting DNA from any organ of an individual, mainly muscle, we tag all the DNA fragments of each individual using short DNA sequences that we know and that are unique for each specimen. The DNA is then sequenced, and through bioinformatic tools, it is possible to identify all the sequences of the same organism within a large data set containing sequences from multiple organisms.

Lab procedure to tag the DNA of each individual. A plate with 96 holes with one organism per hole. Photo © Fausto Valenzuela

We made two pools with forty-eight individuals each. For one pool we obtained 262,387,764 raw sequences, and for the other pool we obtained 222,756,694. In both pools, we have few sequences containing ambiguity bases (0,01%) or low-quality (0.00%). This is the first quality control with bioinformatic tools after the sequencing run.

The pie chart indicates the percentage of clean sequences, sequences containing ambiguous bases, and low-quality sequences for the second pool.

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