to a sequence selected from the group consisting of the t2r dna sequences disclosed infra and conservatively modified variants thereof 4 comprise a sequence at least about 40 identical to an amino acid sequence selected from the group consisting of the t2r amino acid sequences disclosed infra or 5 are amplified by primers that specifically hybridize under stringent hybridization conditions to the described t2r sequences in particular these u201c t2r 39 s u201d include taste receptor gpcrs referred to herein as ht2r1 ht2r3 ht2r4 ht2r5 ht2r7 ht2r8 ht2r9a ht2r9v ht2r10 ht2r13 ht2r14 ht2r16 ht2r44 ht2r50 ht2r54 ht2r55 ht2r61 ht2r64 ht2r65 ht2r67 ht2r71 ht2r75 and ht2r76 having the nucleic acid sequences and amino acid sequences provided in this application and variants alleles mutants orthologs and chimeras thereof which specifically bind to bitter ligands which are identified herein and other structurally related compounds and bitter compounds as noted in the table in fig1 the ht2rs herein have also been referred to in the literature by other names herein when applicants refer to a t2r sequence the senomyx nomenclature is intended while t2r genes exhibit substantial sequence divergence at both the protein and dna level all t2rs isolated to date have been found to contain certain consensus sequences in particular regions that are identical or which possess or at least 70 75 sequence identity to the t2r consensus sequence identified previously in the adler et al wo 01 77676 a1 2001 and zuker et al wo 01 18050 a2 both incorporated by reference in their entirety herein topologically certain chemosensory gpcrs have an u201c n terminal domain u201d u201c extracellular domains u201d a u201c transmembrane domain u201d comprising seven.