Some animals have a trick: dark ears, a glowing tail, blood that does not freeze. Each trick comes down to
one protein. Read a file, guess the reason, then tap to check.
the Sketcher's drawingPrediction Computed by a model, with how sure it is. Not an experiment.
Each protein is drawn the way AlphaFold predicts it, one tick per building block from start to end:
in ink where AlphaFold is sure (confidence 70 or more), in pencil where it is
less sure.
Siamese cat: dark ears, face, paws and tail
The protein: Tyrosinase from Felis catus · UniProt P55033 · 529 building blocks
470 of 529 building blocks in ink, 59 in pencil. AlphaFold DB model v6. A prediction, not an experiment.
A Siamese cat is pale, but its ears, face, paws and tail are dark. Why?
de Wet JR, Wood KV, DeLuca M, Helinski DR, Subramani S (1987). Firefly luciferase gene: structure and expression in mammalian cells. Molecular and Cellular Biology 7, 725–737. doi:10.1128/mcb.7.2.725
Conti E, Franks NP, Brick P (1996). Crystal structure of firefly luciferase throws light on a superfamily of adenylate-forming enzymes. Structure 4, 287–298. doi:10.1016/S0969-2126(96)00033-0
Jellyfish: a green glow
The protein: Green fluorescent protein from Aequorea victoria · UniProt P42212 · 238 building blocks
235 of 238 building blocks in ink, 3 in pencil. AlphaFold DB model v6. A prediction, not an experiment.
Shine ultraviolet or blue light on this jellyfish protein and it glows green. Where does the glow come from?
Ormö M, Cubitt AB, Kallio K, Gross LA, Tsien RY, Remington SJ (1996). Crystal structure of the Aequorea victoria green fluorescent protein. Science 273, 1392–1395. doi:10.1126/science.273.5280.1392
Jia Z, DeLuca CI, Chao H, Davies PL (1996). Structural basis for the binding of a globular antifreeze protein to ice. Nature 384, 285–288. doi:10.1038/384285a0
Fletcher GL, Hew CL, Davies PL (2001). Antifreeze proteins of teleost fishes. Annual Review of Physiology 63, 359–390. doi:10.1146/annurev.physiol.63.1.359
Bar-headed goose: flying over the Himalayas
The protein: Hemoglobin subunit alpha-A from Anser indicus · UniProt P01990 · 142 building blocks
141 of 142 building blocks in ink, 1 in pencil. AlphaFold DB model v6. A prediction, not an experiment.
Next to the western greylag goose (UniProt P01989), this chain differs at 3 places: 19, 64, 120.
The bar-headed goose flies over the Himalayas, where the air holds much less oxygen. What helps it?
Jessen TH, Weber RE, Fermi G, Tame J, Braunitzer G (1991). Adaptation of bird hemoglobins to high altitudes: demonstration of molecular mechanism by protein engineering. PNAS 88, 6519–6522. doi:10.1073/pnas.88.15.6519
Hawkes LA, et al. (2011). The trans-Himalayan flights of bar-headed geese (Anser indicus). PNAS 108, 9516–9519. doi:10.1073/pnas.1017295108
Where this comes from
Each protein is the reviewed UniProt entry for that creature, found by its gene (or, for the firefly, its enzyme
number, and for the ocean pout, the name of that one antifreeze protein). The ink and pencil come from the
AlphaFold Database's confidence for every building block (CC BY 4.0), snapshot 2026-10-08. Each reason is
checked against the paper listed under it.