The Institute of Liver and Biliary Sciences (ILBS) COVID-19 sequencing lab in Delhi that was started in July this year has sequenced almost 1,500 samples of the virus so far, the majority are Delta.
ANI received access to the lab exclusively to unravel the process behind the sequencing. Dr Pramod Gautam, Manager at COVID-19 sequencing labs, ILBS explained the whole process that involves various steps before the results come out in six days.
"After RNA Isolation - VTM samples are gone for RNA isolation through appropriate methods. We are involved in COVID-19 Genome Project. This is the lab in which the genome sequencing part is done. After we received the VTM samples, we isolate the purified RNA. After we get the purified RNA, the rest of the work happens in this lab. So in genome sequencing, the process starts from getting purified RNA. It's a multi-step process it takes at least five days. And in those five days, that RNA is basically chemically modified to a multi-step process. As you can see in this summary," said Dr Gautam.
"This process is called library preparation, RNA basically goes through a process called library preparation before it goes into the sequencer, because as you might have known the SARS COVID 2 virus genome is 30,000 bases long. We basically break it into small 200 to 300 base pieces, which are chemically modified by the process of chemical modification. In order to convert it into DNA, we attach sequences which are called index sequences. Because in one go we cannot do sequencing for each sample separately. Hence we do the sequencing of the 384 samples together. But in order to identify the origin, from which individual they came from, we attach short sequences and short chemicals," added Dr Gautam.
"In order to identify the lineage or in which individual the variant is found, we need to study the process of RNA isolation. It takes a minimum of seven to eight days to study the process of RNA isolation," he added.
The ILBS genome sequencing is designated for the south zone in Delhi from where they get samples for genome sequencing. "We get sequencing samples as per the government guidelines, so we are only designated the South Zone as per the positivity, positivity rating, we get sick samples for sequencing. We have done sequencing of around 1000 to 1500 samples."
"The next important step is to check the quality of this library because the sequencing word that we use to analyse and this is that by which we load this library and check the data. The next important step before sequencing is to check the library. So, for that, we use Bioanalyzer machines to check the libraries," said Dr Varun, Bioinformatician, COVID-19 sequencing lab, ILBS.
( With inputs from ANI )
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