Genomewide

Genomewide is an adjective used in genomics to describe analyses, data sets, or experiments that cover the entire genome, rather than focusing on individual genes or regions. Genomewide approaches survey large numbers of genomic elements—such as variants, transcripts, epigenetic marks, or regulatory sequences—across the whole genome. The term is commonly encountered in both research and clinical genetics and is often hyphenated as genome-wide in many style guides.

Common genomewide applications include genomewide association studies (GWAS), which scan hundreds of thousands to millions of genetic variants to identify associations with traits or diseases; genomewide expression analyses, typically based on RNA sequencing, to quantify transcripts across all genes; and genome-wide methylation or chromatin accessibility studies that profile epigenetic marks across the genome. In functional genomics, genomewide screens using CRISPR, RNAi, or transposon mutagenesis test many genes for a given phenotype.

Advantages of genomewide approaches include the ability to discover contributors without prior hypotheses and to reveal unexpected biology. Limitations include substantial multiple-testing burdens, the need for large sample sizes, potential confounding by population structure and batch effects, and the computational demands of data processing and integration across diverse data types.

Notes: genomewide usage varies, with genome-wide being a common hyphenated form in many scientific journals.