Which of the following is a crucial technology in the field of genomics for studying gene expression?

Microarrays are a crucial technology in the field of genomics specifically for studying gene expression. This allows researchers to analyze the expression levels of thousands of genes simultaneously. Microarrays consist of a glass slide or a silicon chip that has been coated with small spots of DNA or RNA sequences. These sequences hybridize with complementary sequences from RNA samples extracted from cells, providing a vast amount of data on which genes are active and to what extent.

The ability of microarrays to facilitate high-throughput analysis is significant because it enables researchers to identify patterns of gene expression, which can be critical in understanding various biological processes, disease states, or responses to treatments. This technology has led to advancements in personalized medicine and significant insights into complex conditions, including cancer and genetic disorders.

Other options, while important in their respective contexts, do not serve the specific purpose of high-throughput gene expression analysis. Western blotting is primarily used for protein detection and quantification, gene therapy focuses on treating diseases by introducing or modifying genes, and cell culture is a technique for growing cells in a controlled environment, which does not inherently measure gene expression on a genomic scale.