@article {8318, title = {High-quality single amplicon sequencing method for illumina MiSeq platform using pool of {\textquoteright}N{\textquoteright} (0-10) spacer-linked target specific primers without PhiX spike-in [Next Gen Genomics Facility (INT)]}, journal = {BMC Genomics}, volume = {24}, year = {2023}, month = {2023 Mar 23}, pages = {141}, abstract = {

BACKGROUND: Illumina sequencing platform requires base diversity in the initial 11 cycles for efficient cluster identification and colour matrix estimation. This limitation yields low-quality data for amplicon libraries having homogeneous base composition. Spike-in of PhiX library ensures base diversity but reduces the overall number of sequencing reads for data analysis. To overcome such low diversity issues during amplicon sequencing on illumina platforms, we developed a high throughput single amplicon sequencing method by introducing {\textquoteright}N{\textquoteright} (0-10) spacers in target gene amplification primers that are pooled for simple handling.

RESULT: We evaluated the efficiency of {\textquoteright}N{\textquoteright} (0-10) spacer-linked primers by targeting bacterial 16S V3-V4 region, demonstrating heterogeneous base library construction. The addition of {\textquoteright}N{\textquoteright} (0-10) spacers causes sequencing frameshift at every base that leads to base diversity and produces heterogeneous high quality reads within a single amplicon library. We have written a python based command-line software,"MetReTrim", to trim the {\textquoteright}N{\textquoteright} (0-10) spacers from the raw reads ( https://github.com/Mohak91/MetReTrim ). We further demonstrated the accuracy of this method by comparative mock community analysis with standard illumina V3-V4 primer method. The ZymoBIOMICS{\texttrademark} microbial community DNA standard was used as a control for this study. We performed data analysisusing the DADA2 pipeline where taxonomy was assigned using SILVA database as reference. We observed no difference between the communities represented by our method and standard illumina V3-V4 primer method.

CONCLUSION: This method eliminates the need for PhiX spike-in for single amplicon sequencing on illumina MiSeq platform. This allows for sequencing of more number of samples in a run and a reduction in the overall cost. Given that Illumina sequencing works on SBS chemistry irrespective of the platform (such as HiSeq, MiSeq, NextSeq, NovaSeq, etc.) we propose that this strategy of using {\textquoteright}N{\textquoteright} (0-10) spacer-linked primer design can be adopted for generating high-quality single locus amplicon sequencing in a high throughput manner across the illumina platform subject to further validation.

}, keywords = {Bacteria, Gene Library, High-Throughput Nucleotide Sequencing, Microbiota, RNA, Ribosomal, 16S, Sequence Analysis, DNA}, issn = {1471-2164}, doi = {10.1186/s12864-023-09233-4}, author = {Naik, Tejali and Sharda, Mohak and C P, Lakshminarayanan and Virbhadra, Kumar and Pandit, Awadhesh} } @article {493, title = {Deep sequencing reveals unique small RNA repertoire that is regulated during head regeneration in Hydra magnipapillata. [Next Generation Genomics facility]}, journal = {Nucleic Acids Res}, volume = {41}, year = {2013}, month = {2013 Jan 07}, pages = {599-616}, abstract = {

Small non-coding RNAs such as miRNAs, piRNAs and endo-siRNAs fine-tune gene expression through post-transcriptional regulation, modulating important processes in development, differentiation, homeostasis and regeneration. Using deep sequencing, we have profiled small non-coding RNAs in Hydra magnipapillata and investigated changes in small RNA expression pattern during head regeneration. Our results reveal a unique repertoire of small RNAs in hydra. We have identified 126 miRNA loci; 123 of these miRNAs are unique to hydra. Less than 50\% are conserved across two different strains of Hydra vulgaris tested in this study, indicating a highly diverse nature of hydra miRNAs in contrast to bilaterian miRNAs. We also identified siRNAs derived from precursors with perfect stem-loop structure and that arise from inverted repeats. piRNAs were the most abundant small RNAs in hydra, mapping to transposable elements, the annotated transcriptome and unique non-coding regions on the genome. piRNAs that map to transposable elements and the annotated transcriptome display a ping-pong signature. Further, we have identified several miRNAs and piRNAs whose expression is regulated during hydra head regeneration. Our study defines different classes of small RNAs in this cnidarian model system, which may play a role in orchestrating gene expression essential for hydra regeneration.

}, keywords = {Animals, Gene Expression Regulation, Head, High-Throughput Nucleotide Sequencing, Hydra, MicroRNAs, Regeneration, RNA, Small Interfering, RNA, Small Untranslated, Sequence Analysis, RNA, Transcriptome}, issn = {1362-4962}, doi = {10.1093/nar/gks1020}, author = {Krishna, Srikar and Nair, Aparna and Cheedipudi, Sirisha and Poduval, Deepak and Dhawan, Jyotsna and Palakodeti, Dasaradhi and Ghanekar, Yashoda} }