Final Answer:
Two approaches to study global gene expression are microarray analysis, which examines gene expression levels through hybridization, and RNA sequencing (RNA-seq), which uses high-throughput sequencing to quantify RNA molecules in a sample.
Step-by-step explanation:
Two prominent approaches to study global gene expression are microarray analysis and RNA sequencing (RNA-seq). Microarray analysis involves hybridizing labeled cDNA or RNA to a microarray chip containing probes for thousands of genes. The intensity of signals indicates the level of gene expression. This method enables the simultaneous examination of a large number of genes, providing insights into global expression patterns.
RNA-seq, on the other hand, utilizes high-throughput sequencing technologies to sequence and quantify RNA molecules in a sample. It offers a comprehensive view of the transcriptome, detecting known and novel transcripts, alternative splicing, and gene fusion events. RNA-seq is highly sensitive, providing quantitative data with a wide dynamic range and offering insights into transcriptional complexity.
Both methods have contributed significantly to understanding global gene expression patterns in diverse biological contexts, from development and disease to environmental responses. The choice between them depends on factors like sensitivity, cost, and the specific research questions being addressed.