The study received approval from the Ethical committee of the University of Calabria. All participants provided written informed consent for the aging study carried out by our research group. White blood cells (WBC) from blood buffy coats were used as a source of DNA. Between 1994 and 2008, 941 unrelated individuals were recruited in Calabria, including 348 very elderly cases ($85 years, range 85106 years, mean age 93.8264.44 years, median age 92) and 593 non-elderly controls (,85 years, range 2084 years, mean age 59.17619.45 years, median age 67 years). We selected 85 as a cut-off point since genetic factors contribute minimally to human life span variation before age 60 and more profoundly from age 85 [13]. Study participants and their parents were selected for tagging single nucleotide polymorphisms (SNPs) in bitter taste receptors located on chromosomes 5, 7, and 12. We used a hybrid tagging-functional approach that selected all common genetic variants in these regions. The Tagger program within Haploview was used to select tagging SNPs with pairwise tagging and a minimum r2 of 0.8. We included all polymorphisms with minor allele frequency (MAF) $5% in Caucasians from the International HapMap Project version 28 (August 2010). The final selection included 41 SNPs belonging to 20 genes. Figures 1-3 show the selected polymorphisms in each region along with distance and linkage disequilibrium between SNPs within the same chromosome. DNA was extracted from blood samples using standard proteinase K digestion followed by phenol/chloroform extraction and ethanol precipitation. Genotyping was carried out using Kaspar or Taqman assays and PCR plates were read on an ABI PRISM 7900HT instrument. Individual haplotypes were statistically inferred using the PHASE v.2.1.1 algorithm based on a Bayesian approach. The distribution of genotypes and their odds ratios (ORs) for association with longevity are shown in Table S2. We found five significant associations between SNPs in the chromosome 7 cluster and longevity at the conventional level of p<0.05. Only carriers of the G allele of rs978739 variation showed a statistically significant association after correction for multiple testing. Haplotype analysis showed no significant association with longevity, although the TAS2R16 gene haplotype (rs1357949 rs6466849rs860170rs978739: T_A_A_G) showed a suggestive association with longevity (OR=0.74, 95% CI 0.560.98, p=0.033). The haplotype rs2588350 (TAS2R7)- rs619381(TAS2R9)-rs3741845(TAS2R9): G_G_T showed an association with increased longevity at the conventional 0.05 P-value (OR=1.35, 95% CI 1.021.78, p=0.037). No interactions between SNPs emerged with a study-wise significant p-value from pairwise interactions analyzed using the MDR method.
This text appears to be a scientific article discussing the association between longevity and genetic polymorphisms related to bitter taste perception. Here is the processed text:

The chart depicts the age-genotype association between the TAS2R16rs 978739 polymorphism and longevity. The A/A genotype frequency is approximately 40.5% in young and adult classes (20-50 and 51-70 years). Subsequently, the frequency of A/A genotype increases through older classes, reaching 55.5% in the oldest age group (x2=17.08, p<0.029). 

In this study, we investigated possible associations between longevity and 41 SNPs in 20 candidate genes involved in bitter taste perception. Our findings suggest that harmful compounds recognized by these genes throughout an organism's lifespan could modify an individual's chances of reaching old age. However, there is another possible explanation for the involvement of TAS2R16 genetic variability in healthy aging. Recent studies have shown that taste receptors are expressed in various tissues, including the respiratory system, gastrointestinal tract, and testis, where they can affect different physiological functions. Therefore, these genes could behave as pleiotropic genes whose products are used by various cells or have signaling functions on various targets not linked directly to each other.

Our SNP tagging approach and haplotype analysis provide a close-to-exhaustive analysis of the possible associations of longevity with common polymorphic variants at bitter taste receptor loci. We found that five polymorphisms were associated with longevity: three in the TAS2R16 gene (rs6466849, rs860170, and rs978739), one in the TAS2R4 gene (rs2233998), and two in the TAS2R5 gene (rs2227264). After correction for multiple testing, only one polymorphism - rs978739 - showed a statistically significant association with longevity (p=0.001). Specifically, the frequency of homozygotes A/A increased gradually from 35% in the subjects aged 20 to 70 up to 55% in centenarians. A distribution of genotypes through various age strata is given in Figure 4.