What is three levels of bioinformatics

What is three levels of bioinformatics?

1. Analysis of a single gene (protein) sequence. For example:
* Similarity with other known genes
* Phylogenetic trees; evolutionary relationships
* Identification of well-defined domains in the sequence
* Sequence features (physical properties, binding sites, modification sites)
* Prediction of subcellular localization
* Prediction of secondary and tertiary structure
2. Analysis of complete genomes. For example:
* Which gene families are present, which missing?
* Location of genes on the chromosomes, correlation with function or evolution
* Expansion/duplication of gene families
* Presence or absence of biochemical pathways
* Identification of "missing" enzymes
* Large-scale events in the evolution of organisms
3. Analysis of genes and genomes with respect to functional data. For example:
* Expression analysis; microarray data; mRNA conc. measurements
* Proteomics; protein conc. measurements, covalent modifications
* Comparison and analysis of biochemical pathways
* Deletion or mutant genotypes vs. phenotypes
* Identification of essential genes, or genes involved in specific processes