4 Overview of environmental DNA metabarcoding

one way we try to find traces of organismal DNA is with the technique called meta bar coding DNA bar codes are specific regions of the genome that have unique sequences for almost all species using Illumina sequencing machines we can sequence millions of these at once and discover hundreds to thousands of different species that shed DNA into each environmental sample like soil but first we need to make millions of copies of those barcodes in order for the sequencing machine to detect them to do this we use polymerase chain reaction or PCR PCR is a process of mixing DNA with primers that guide a polymerase enzyme to make copies of the bar coding regions of the DNA in a machine called a thermo cycler that heats and cools the mixture cyclically [Music] [Music] researchers check the PCR worked by doing gel electrophoresis on the samples