Genomics and proteomics are becoming powerful tools for revealing gene function and genomic organization in large scale. Genomics is the study of the entire genome, usually starting with whole genome sequencing. Proteomics is the study of the entire protein components within the cells.
The genomics approach has three steps: BAC construction, shot-gun sequencing and sequence assembly. BACs are bacterial artificial chromosomes which can have large inserts of 100 to 300 kb. These large fragment are digested into smaller pieces (shot-gun) and the sequence is determined based on these small plasmids. The small plasmids overlap with each other, so do the BAC DNA. The sequence is then assembled using computer programs.
Functional genomics and proteomics
Functional genomics is about using the sequence data to explore how DNA and proteins work with each other and the environment to create complex, dynamic living systems. The directions include transcriptomics (analysis of transcripts of the whole cell), comparative genomics, structural genomics and proteomics. Transcriptome is mostly studied by a novel method called DNA microarray, where the DNA is spotted on piece of glass and the mRNA is labeled and used as probes. The hybridized signal is then compared to determine gene transcripts level under different condition.
The entirety of proteins in an organism throughout its life cycle, or on a smaller scale the entirety of proteins found in a particular cell type under a particular type of stimulation, is called proteome. The study on proteome is called proteomics. The main tools for proteomics studies include 2D gel electrophoresis, MOLDI-TOF MS and protein array.