TABLE 1.
Notations used in this article
| Symbols | Meaning for the yeast protein-protein interaction dataa |
|---|---|
| a1 | No. of protein interaction partners for duplicate gene 1 |
| a2 | No. of protein interaction partners for duplicate gene 2 |
| s | No. of shared partners between gene 1 and gene 2 |
| t (= a1 + a2 − s) | Total no. of nonredundant partners for gene 1 and gene 2 |
| A | Average no. of partners per singleton gene |
| S | Average no. of shared partners per randomly picked singleton pair |
| T | Average total no. of nonredundant partners per randomly picked singleton pair |
| δ (= |a1 − a2|) | Absolute difference between a1 and a2 |
| min (a1, a2) | The smaller of a1 and a2 |
| max (a1, a2) | The bigger of a1 and a2 |
| dS | No. of synonymous substitutions per synonymous site between a pair of duplicates |
| ISF [= 1 − (s + δ)/t] | Subfunctionalization index |
| SF | Subfunctionalization |
| NF | Neofunctionalization |
| SNF | Subneofunctionalization |
a
The number of interaction partners is substituted by the number of expression sites when human gene spatial expression pattern is concerned.