An integrated view of the correlations between genomic and phenomic variables

Genome sequencing opened the flood gate of "-omics" studies, among which the research about correlations between genomic and phenomic variables is an important part. With the development of functional genomics and systems biology, genome-wide investigation of the correlations between many genomic and phenomic variables became possible. In this review, five genomic variables, such as evolution rate (or "age" of the gene), the length of intron and ORF (protein length) in one gene, the biases of amino acid composition and codon usage, along with the phenomic variables related to expression patterns (level and breadth) are focused on. In most cases, genes with higher mRNA/protein expression level tend to evolve slowly, have less intronic DNA, code for smaller proteins, and have higher biases of amino acid composition and codon usage. In addition, broadly expressed proteins evolve more slowly and are shorter than tissue-specific proteins. Studies in this field are helpful for deeper understanding the signatures of selection mediated by the features of gene expression and are of great significance to enrich the evolution theory.