Table 3.
Selective forces operating on GenAge categories by selection process.
| GenAge categorya | n | Ka/Ks | p-value highb | p-value lowb | n in 4-way comparisonsc | Ka/Ks in hominids | Ka/Ks in murids | Homo AA diff.d | Pan AA diff.d |
|---|---|---|---|---|---|---|---|---|---|
| human | 3 | 0.472 | 0.017 | 0.99 | 2 | 0.46 | 0.22 | 4 | 8 |
| mammal | 21 | 0.331 | 0.0026 | 1 | 9 | 0.32 | 0.20 | 9 | 10 |
| model | 22 | 0.083 | 1 | 4.6E−07 | 14 | 0.069 | 0.10 | 2 | 3 |
| cell | 14 | 0.109 | 1 | 5.7E−4 | 6 | 0.068 | 0.19 | 2 | 1 |
| functional | 55 | 0.184 | 0.99 | 0.017 | 22 | 0.094 | 0.11 | 8 | 4 |
| upstream | 25 | 0.138 | 1 | 1.1E−3 | 15 | 0.18 | 0.21 | 9 | 2 |
| downstream | 46 | 0.097 | 1 | 7.6E−16 | 28 | 0.085 | 0.080 | 22 | 17 |
| putative | 56 | 0.159 | 1 | 2.3E−4 | 38 | 0.15 | 0.13 | 16 | 19 |
Genes linked to aging based on: human = evidence directly linking the gene product to aging in humans; mammal = evidence directly linking the gene product to aging in a non-human mammalian model organism; model = evidence directly linking the gene product to aging in a non-mammalian animal model organism; cell = evidence directly linking the gene product to aging in a cellular model system; functional = evidence linking the gene product to a pathway or mechanism linked to aging; upstream = evidence directly linking the gene product to the regulation or control of genes previously linked to aging; downstream = evidence showing the gene product to act downstream of a pathway, mechanism, or other gene product linked with aging; putative = indirect or inconclusive evidence linking the gene product to aging.
This binomial probability is not used to directly reject the null hypothesis of a given GenAge category not undergoing rapid (probability high) or slow (probability low) evolution but provides a metric to identify categories potentially undergoing rapid or slow evolution. The test statistic threshold was set at 0.001 (see Materials and Methods).
Ka/Ks ratios in hominids are based on 4-way alignments and hence are expected to be different from Ka/Ks ratios based on only chimpanzee and human alignments, as described (Chimpanzee Sequencing and Analysis Consortium, 2005).
Amino acid differences (AA diff.) represent amino acid changes estimated to have occurred specifically in the human (Homo) or chimpanzee (Pan) lineage.