Metabarcoding

Author:

Therese Benz

Keywords:

Subtitles:

are you sick and tired of failing at biology need a more accurate way to catalogue all the species in the environment you're studying now introducing meta barcoding to answer all your environmental analysis needs so what is this numerical technique meta barcoding is a way to use DNA barcoding not to identify a single species but now identify all species in a specific ecological context such as the ecosystem of a stream a single environmental sample such as soil from an ecosystem to contain DNA barcodes from several species within that ecosystem DNA barcodes are short sequences in the genome that are unique to a species and are used to identify an organism as belonging to our particular species we first need to make millions of copies of the barcodes how do we do this we use something called polymerase chain reaction or PCR in PCR the DNA sample is mixed with polymerase enzyme nucleotide bases and primers in the first step the DNA sample is denature next primer is anneal to the specific barcode region we aim to replicate then complementary nucleotide bases add to the denatured strands alongside the primers to double the amount of DNA barcodes this process continues until millions of copies of the barcode are obtained now these millions of copies can be run through a sequence analyzer to determine exactly what species are present in your ecosystem the reads from the DNA sequences are then compared to a database of the genomes of known species allowing us to identify those present sounds awesome right well don't just take my word for it hear from satisfied researchers who use meta bar coding in their lab everyday my research group does research on lakes and we do we measure and ask questions of the diverse nature of our lakes we think a lot about carbon biochemistry so movement of carbon molecules into lakes through lakes and then out lakes and microorganisms mediate a lot of that process when we look at microorganisms in the bottom of Lake or in the water column they all kind of tiny little specks under the microscope if we were able to grow them in the lab on a petri dish or something they all look like these around the colonies and so we can't tell them apart but we know that they're doing very different things in terms of cyclic urbanization careful so one way to figure out who's there and what they're doing this this sequence particular digits if we use this batter by recording process to understand who's there and when they're there may be bad thing about meta marking for microbial analysis or what microbial species are present and absent in samples is that it's it's kind of quantitative we have to think about who's there and who's not in a relative sense we can say some are high and some are low but there are some biases in that houses process that mean that we can't say with by extreme specificity that there are 10 of this organism and 11 of those proteins it's much more this one is higher than this one so that relative abundance for sexual violence turned out to be a clear answer and that's not all wait there's more check this F so my research works to look at the differences between these populations of monkeys and Southeast Asia so if we were to go and look at say the bacteria and the mounts of these monkeys and we didn't have meta barcoding we would be really limited because all we could do is say scrape the inside of their mouth and try to grow that bacteria and then see what is growing on that plate but there are a lot of bacteria that we can't grow that way because they require different environments than what is present on a plate or present on some agar so like some can't grow with too much error with not enough and there are also a lot of environments that bacteria are not able to grow that we don't really know how to make them grow at all so meta bar coding allows us to completely skip around that question by just taking a slice of what is there and then comparing it to all the bacteria that we know of that have ever been cataloged by researchers and we can sort of compare it to that database and see what bacteria is there without needing to try to grow in any way a disadvantage is that we only get what's there at one time point so if there is a question like it's the monkeys let's say start eating some specific type of plant that they haven't really eaten before and we want to know what the effect is on what bacteria are able to live in their stomach we don't really have the ability to answer that question because we don't have different time points of that data from an entire lake down to the mouths of monkeys join these and dozens of other researchers and seeing what meta bar coding can do for you today Wow