Table 1.
Mutations hypothesized to cause evolutionary events of loss of the sweet taste receptor in Carnivora.
| Eventa | Taxon affected | Mutation’s genomic location | Mutationb | Reference | |
|---|---|---|---|---|---|
| Gene | Exon | ||||
| A | Lontra longicaudis | TAS1R2 | Exon 4 | 1-bp deletion | Fig. 1G |
| TAS1R3 | Exon 3 | 1-bp insertion | Fig. 1P | ||
| B | Lutra lutra | TAS1R2 | Exon 3 | 4-bp insertionc | Fig. 1I |
| Exon 6 | 7-bp insertion | Fig. 1J | |||
| TAS1R3 | Exon 1 | Start codon homozygous substitution | Fig. 1Q | ||
| Exon 6 | 1-bp insertion | Fig. 1R | |||
| 2-bp deletion | Fig. 1S | ||||
| C | Amblonyx cinereus | TAS1R2 | Exon 3 | 1-bp insertion | Fig. 1K; Jiang et al. 2012a: Fig. 1B |
| TAS1R3 | Exon 1 | Homozygous nonsense substitution | Fig. 1T | ||
| Exon 3 | Homozygous nonsense substitution | Fig. 1U | |||
| D | Enhydra lutris | TAS1R2 | Exon 3 | 1-bp deletion | Fig. 1L |
| E | Lyncodon patagonicus | TAS1R2 | Exon 4 | 1-bp deletion | Fig. 1M |
| F | Phocidae | TAS1R2 | Exon 6 | Homozygous nonsense substitution | Wolsan and Sato 2020: mutation S15 |
| TAS1R3 | Exon 3 | 1-bp deletion | Wolsan and Sato 2020: mutation US11 | ||
| Exon 6 | 1-bp deletion | Wolsan and Sato 2020: mutation US35 | |||
| 1-bp deletion | Wolsan and Sato 2020: mutation US36 | ||||
| G | Otarioidea | TAS1R2 | Exon 1 | Start codon homozygous substitution | Wolsan and Sato 2020: mutation S1 |
| Exon 3 | 2-bp deletion | Wolsan and Sato 2020: mutation S12 | |||
| Exon 5 | Homozygous nonsense substitution | Wolsan and Sato 2020: mutation S13 | |||
| Exon 6 | 1-bp deletion | Wolsan and Sato 2020: mutation S21 | |||
| TAS1R3 | Exon 6 | 14-bp deletion | Wolsan and Sato 2020: mutation US30 | ||
| H | Felidae | TAS1R2 | Exon 3 | 247-bp deletion | Li et al. 2005: Fig. 1 |
| I | Prionodon linsang | TAS1R2 | Exon 2 | 1-bp insertion | Jiang et al. 2012a: Fig. 1B |
| 10-bp deletion | Jiang et al. 2012a: Fig. S6B | ||||
| Exon 4 | 14-bp insertion | Jiang et al. 2012a: Fig. S6C | |||
| Exon 5 | 20-bp deletion | Jiang et al. 2012a: Fig. S6D | |||
| 2-bp deletion | Jiang et al. 2012a: Fig. S6E | ||||
| Exon 6 | 1-bp deletion | Jiang et al. 2012a: Fig. S6F | |||
| 28-bp insertion | Jiang et al. 2012a: Fig. S6G | ||||
| 1-bp deletion | Jiang et al. 2012a: Fig. S6H | ||||
| J | Cryptoprocta ferox | TAS1R2 | Exon 3 | Homozygous nonsense substitution | Jiang et al. 2012a: Fig. 1B |
| Exon 4 | 1-bp insertion | Jiang et al. 2012a: Fig. S5B | |||
| K | Crocuta crocuta | TAS1R2 | Exon 2 | 1-bp deletion | Jiang et al. 2012a: Fig. 1B |
aAll events are illustrated in Fig. 3A.
bMutations within the same exon are listed in order from the 5ʹ to 3ʹ end.
cOther otters (Lontra longicaudis, Lontra canadensis, Amblonyx cinereus, Enhydra lutris) have instead a 3-bp (CCC) insertion, which suggests that the frameshift in Lutra lutra has effectively been caused by a 1-bp insertion, an extra repeat of C, rather than the 4-bp (CCCC) insertion (Fig. 2C).