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The extent to which taste receptor specificity correlates with, or even predicts, diet choice is not known. We recently reported that the insensitivity to sweeteners shown by species of Felidae can be explained by their lacking of a functional Tas1r2 gene. To broaden our understanding of the relationship between the structure of the sweet receptors and preference for sugars and artificial sweeteners, we measured responses to 12 sweeteners in 6 species of Carnivora and sequenced the coding regions of Tas1r2 in these same or closely related species. The lion showed no preference for any of the 12 sweet compounds tested, and it possesses the pseudogenized Tas1r2. All other species preferred some of the natural sugars, and their Tas1r2 sequences, having complete open reading frames, predict functional sweet receptors. in addition to preferring natural sugars, the lesser panda also preferred 3 (neotame, sucralose, and aspartame) of the 6 artificial sweeteners. Heretofore, it had been reported that among vertebrates, only Old World simians could taste aspartame. The observation that the lesser panda highly preferred aspartame could be an example of evolutionary convergence in the identification of sweet stimuli. [ABSTRACT FROM AUTHOR]

Translocation of mtDNA into the nuclear genome, also referred to as numt, was first reported in the domestic cat (Felis catus) by Lopez et al. (1994). The Lopez-numt consisted of a translocation of 7.9 kbp of mtDNA that inserted into the domestic cat chromosome D2 around 1.8 million years ago. More than a decade later, the release of the domestic cat whole-genome shotgun sequences (1.9 x coverage) provides the resource to obtain more comprehensive insight into the extent of mtDNA transfer over time in the domestic cat genome. MegaBLAST searches revealed that the cat genome harbors a wide variety of numts (298 320 bp), one-third of which likely correspond to the Lopez-numt tandem repeat, whereas the remaining numts are probably derived from multiple independent insertions, which in some cases were followed by segmental duplication after insertion in the nucleus. Numts were detected across most cat chromosomes, but the number of numts assigned to chromosomes is underestimated due to the relatively high number of numt sequences with insufficient flanking sequence to map. The catalog of cat numts provides a valuable resource for future studies in Felidae species, including its use as a tool to avoid numt contaminations that may confound population genetics and phylogenetic studies. [ABSTRACT FROM AUTHOR]