Question

How could an investigator identify which genes are being expressed in a cell or population of cells at a specific time or under a specific condition? Use microarray analysis Use RNA-Seq O Query the metatranscriptome Through proteomic analysis All of the above

Answer 1

Microarray analysis is used to study the expressions of thousands of genes at the same time. These consist of  microscope slides printed with thousands of tiny spots in specific positions and each spot containing a known DNA sequence (DNA chips).

These specific DNA sequences at each spot act as probes to which the complementary RNA can come can bind. By this we study the whole transcriptome, which is the mRNA that are expressed or encode proteins.

RNA-Seq is a technique which uses Next Generation Sequencing (NGS) to reveal the presence and quantity of RNA in a biological sample at a particular moment. It allows us to analyze the transcritome under any given cellular condition. It allows one to study alternative splicing, post-transcriptional modifications, gene fusion, mutations/SNPs and changes in gene expression over time under a given condition.

Metatranscriptomics analysis allows us to stdy the microbial expression profiles under the natural environmental conditions. It helps us study diversity of the active genes within a microbial community, quantify expression levels and to monitor how these levels change in different environmental conditions

Proteomic analysis commonly involves the use of mass spectrometry to analyse the systematic identification and quantification of the full complement of proteins in a biological system at any specific time point. Knowing the proteins expressed at a particular time one may easily know the gene expression profile of the system.

Thus, all these techniques can be used to study the expression profile of a biological system at a specific time point.