Table 1.
Cross-species sequence comparisons suggest origins of the p.N314D and p.L218(TTA) polymorphisms and 5′ promoter deletion characteristic of the D1 and D2 alleles of GALT
| Sequence | Humans (European)a | Other hominids | Other primates | Other placental mammals |
|---|---|---|---|---|
| Amino acid at residue 314 | Asparagine (N) ∼89% | Aspartate (D) | Aspartate (D) | Aspartate (D) |
| Aspartate (D) ∼11% | ||||
| Sequence at residue 218 | CTA (Leu) ∼96% | CTA (Leu) | CTA (Leu) | Some CTA (Leu) |
| TTA (Leu) ∼4% | Some TTA (Leu) | |||
| GTCA repeats | (GTCA)3 in control and D1 alleles | (GTCA)3 | (GTCA)2 | (GTCA)1 |
| (GTCA)2 in D2 alleles |
Species examined that encode D at residue 314 included: chimp, gibbon, gorilla, orangutan, rhesus, galago, tree shrew, mouse, rat, guinea pig, shrew, dog, cat, horse, cow and armadillo. Species examined encoding N at residue 314 included human only. Species examined with p.L218(CTA) included: chimp, gibbon, gorilla, orangutan, rhesus, galago, tree shrew, dog, cat, horse and armadillo. Species examined with p.L218(TTA) included: mouse and rat. Of note, cow GALT encodes p.L218(CTT), whereas guinea pig and rabbit GALT encode p.L218(CTG). Species examined that carry a 5′ (GTCA)3 included: chimp, gibbon, gorilla and orangutan. Species examined that carry a 5′ (GTCA)2 included: rhesus and macaque. Species examined that carry a 5′ (GTCA)1 included: tree shrew, mouse, rat, guinea pig, shrew, hedgehog, dog, cat, cow, elephant and armadillo. Notably, horses carry one copy of ATCA in place of the GTCA sequence found in other species.