From: Evolution of the vertebrate insulin receptor substrate (Irs) gene family
 | Speciesa | Irs1 b | Irs2 b | Irs3 b | Irs4 b |
---|---|---|---|---|---|
Mammals | 43 | 81 | 42 | 81 (73) | 39 | 73 (28) | 31 | 38 (29) | 42 | 78 (51) |
Birds | 5 | 54 | 5 | 51 (4) | 5 | 32 (5) | 0 | 0 (0) | 5 | 54 (4) |
Reptiles | 2 | 5 | 2 | 5 (4) | 2 | 5 (1) | 2 | 5 (4) | 2 | 5 (4) |
Amphibians | 1 | 2 | 1 | 2 (1) | 1 | 1 (1) | 1 | 1 (1) | 1 | 2 (2) |
Lobe-finned fish | 1 | 1 | 1 | 1 (1) | 1 | 1 (1) | 1 | 1 (1) | 1 | 1 (0) |
Bony fish | 11 | 25 | 3 | 5 (5) | 21 | 44 (43) | 21 | 49 (46) | 21 | 47 (29) |
Cartilaginous fish | 1 | 1 | 1 | 1 (1) | 1 | 1 (1) | 0 | 0 (0) | 1 | 1 (1) |
Jawless fish | 1 | 0 | 0 | 0 (0) | 1 | 0 (0) | 0 | 0 (0) | 0 | 0 (0) |
Total | 65 | 167 | 55 | 146 (89) | 71 | 157 (80) | 56 | 94 (81) | 73 | 188 (91) |