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Questions and Answers List

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QuestionAnswer
what does bioinformatics deals with?any thing that interests biologists , DNA/protein sequences, DNA variation, Gene expression (microarrays), data from experiment , images/models, articles.
what are the first methods of DNA sequencing?maxam- gilbert it was based on chemical reactions using large amounts of purified , end-labeled DNA, not used at large scales and sanger sequencing using small amounts of DNA in any form its enzymatic.
what is Shotgun sequencing?its a large scale sequencing on random DNA strands (used for the first genomes) , used restriction enzymes to cut large fragments into short ones making genomic libraries which are then separated and sequenced , then finally assembled on overlapping regions. its expensive and laborious .
what's high-throughput sequencing ?this is intended to lower the cost of DNA sequencing , with the standard dye-terminator method increasing the speed. it applies to exon, genome sequencing transcriptome profiling.
what are the main NGS platforms?illumina solexa (1-6 GB),ABI solid (80-100Gb), paBio ( 100-200gb)
what happed to the cost of DNA sequencing in the NGS era?the cost of Sequencing stimulated by the genome project decreased drastically in an exponentially, and it also became much faster.
why did the cost of sequencing decrease?because of the increase of pre-processing (sample collection) and post processing (bioinformatic analysis). that's why its important in all labs.
how is the genome analyzed?storage of primary sequences, assembly of chromosomal sequences, predictions of gene locations, gene annotation (predicting their function),chromosome composition (variation).
what's metagenomics?it involves directly sequencing samples from various locations, samples of living organisms in their natural environments. to identify the species, characterize their abundance, discover new protein.
what is the DNA chip technology ?1-cell culture/tissue,2- RNA extraction, synthesis of florescent cDNA
what's transcriptome analysis?its defined as the set of all RNA molecules transcribed from genome ,gene expression is tightly regulated each expressed at a different level depending of cell type, tissue, time.
what are the two types of proteome analysis ? how to they work?(2D-page) electrophoresis , and chip on chip analysis : by first tagging of transcription factors with a protein fragment they immobilizing it with fixative agents, fragmenting dNA then Precipitation of DNA-protein complexes, then unbinding them. measurement of DNA enrichment when two extracts are co-hybridized on microarray(chip) each containing one DNA fragment likely to bind.
what's an intractome?a network of complexes.
why do we need biological data bases?1- for storing and communicating large datasets, 2-make these datasets available for scientist,3- making data available in computer-readable forms.
what are some examples of bimolecular databases?sequence and structure databases (UniPort), genome sequences and annotations (NCBI), molecular functions (EXpasy), biological processes (GeneNet)
what's the difference between primary and secondary (derived) databases?primary databases are experimental results directly inputed into databases , secondary databases are results of analysis of primary databases, aggregate of many databases have links to other data items, combination of data and consolidation data.
what's the availability of databases?its publicly available no restriction, with copyright , not downloadable, academic but not freely available , commercial . every year new databases are created with the first issue being open access.
what are some nucleic sequence databases ?GenBank 1979 USA, EMBL-EBI 1974 UK,and DDBJ 1986 Japan
what's the INSDC?ints the international nucleotide sequence database collaboration of (DDBJ, EMBL-EBI, and NCBI)
what is the rule with regarding publishing articles that have sequencing?the sequence has to be deposited in a reference database in any of the 3 databases, they are automatically sincronised.
what's the sequencing pace ?nucleic sequences , Entire genomes, protein sequencing (by translation of gene not direct)
how is data of sequences submitted?direct submission from author by web or email, sequences between banks is identical.
what are the sequence format?Fast A, GenBank (protein ID N)