The European starling, Sturnus vulgaris, is an ecologically significant, globally invasive avian species that is also suffering from a major decline in its native range. Here, we present the genome assembly and long-read transcriptome of an Australian-sourced European starling (S. vulgaris vAU), and a second North American genome (S. vulgaris vNA), as complementary reference genomes for population genetic and evolutionary characterisation. S. vulgaris vAU combined 10x Genomics linked-reads, low-coverage Nanopore sequencing, and PacBio Iso-Seq full-length transcript scaffolding to generate a 1050 Mb assembly on 1,628 scaffolds (72.5 Mb scaffold N50). Species-specific transcript mapping and gene annotation revealed high structural and functional completeness (94.6% BUSCO completeness). Further scaffolding against the high-quality zebra finch (Taeniopygia guttata) genome assigned 98.6% of the assembly to 32 putative nuclear chromosome scaffolds. Rapid, recent advances in sequencing technologies and bioinformatics software have highlighted the need for evidence-based assessment of assembly decisions on a case-by-case basis. Using S. vulgaris vAU, we demonstrate how the multifunctional use of PacBio Iso-Seq transcript data and complementary homology-based annotation of sequential assembly steps (assessed using a new tool, SAAGA) can be used to assess, inform, and validate assembly workflow decisions. We also highlight some counter-intuitive behaviour in traditional BUSCO metrics, and present BUSCOMP, a complementary tool for assembly comparison designed to be robust to differences in assembly size and base-calling quality. Finally, we present a second starling assembly, S. vulgaris vNA, to facilitate comparative analysis and global genomic research on this ecologically important species.

Animals innately prefer caloric sugars over non-caloric sweeteners. Such preference depends on the sugar entering the intestine. [1][2][3][4] Although the brain is aware of the stimulus within seconds, [5][6][7][8] how the gut discerns the caloric sugar to guide choice is unknown. Recently, we discovered an intestinal transducer, known as the neuropod cell. 9,10 This cell synapses with the vagus to inform the brain about glucose in the gut in milliseconds. 10 Here, we demonstrate that neuropod cells distinguish a caloric sugar from a non-caloric sweetener using the electrogenic sodium glucose co-transporter 1 (SGLT1) or sweet taste receptors. Activation of neuropod cells by non-caloric sucralose leads to ATP release, whereas the entry of caloric sucrose via SGLT1 stimulates glutamate release. To interrogate the contribution of the neuropod cell to sugar preference, we developed a method to record animal preferences in real time while using optogenetics to silence or excite neuropod cells. We discovered that silencing these cells, or blocking their glutamatergic signaling, renders the animals unable to recognize the caloric sugar. And, exciting neuropod cells leads the animal to consume the non-caloric sweetener as if it were caloric. By transducing the precise identity of the stimuli entering the gut, neuropod cells guide an animal's internal preference toward the caloric sugar. Main TextThe cephalic senses guide our decision to eat. But what happens next, inside the gut, is essential for our eating preferences.As early as 1952, it was known that animals prefer the side of a T-maze if rewarded by nutrients delivered directly into the stomach. 1 Although the responses depend on the nutrient's caloric value, 7,8,11 how this value is signaled by the gut epithelium to drive preference is unknown. Of all macronutrients, sugars and available analogs have the most defined sensory properties. For instance, sucrose -a compound sugar made of D-glucose and fructose-contains both taste and calorie, whereas non-caloric sweeteners, like sucralose, carry only taste. Animals have an innate preference for sucrose over non-caloric sweeteners, even in the absence of taste. 3,12-14 Such preference depends on the sugar entering the intestine. 2,3,15,16 But slow acting intestinal hormones cannot account for the effect, 17 because the brain perceives stimuli from nutrients entering the small intestine within seconds. 6,8,10 Thus, a fast intestinal sensor must exist to steer the animal towards the caloric sugar.A gut sense for sweets. Intestinal signals arising from the lumen are relayed to the brain via the vagus nerve. 6,10,11 The vagus responds within seconds to an intraluminal stimulus of sucrose, 6,10,18 but the response to other sugars, including non-caloric sweeteners, is unclear. We therefore tested vagal firing responses to a panel of sugars: sucrose, D-glucose, fructose, galactose, maltodextrin, alpha-methylglucopyranoside (α-mgp), saccharin, acesulfame-K, and sucralose. All stimuli were perfused at physiological concentrati...