text: The ANKK1 gene is closely linked to dopamine receptor D2 (DRD2) on chromosome band 11q23.1. The A1 allele of the Taq1A polymorphism (rs1800497T), is located ≈10kb downstream of the dopamine receptor DRD2 gene. Dopamine (DA) is a neurotransmitter in the brain, which controls feelings of wellbeing. This sensation results from the interaction of dopamine and other neurotransmitters such as serotonin, the opioids, and other brain chemicals. Dopamine increases the motivation for food cravings and appetite mediation.
  The Reward Deficiency Syndrome (RDS) involves the pleasures or reward mechanisms that rely on dopamine. The result of this deficiency is based on the genetic makeup; this helps explain how certain simple genetic anomalies can give rise to complex aberrant behaviours as the ones mentioned previously. The A1 allelic prevalence has been reported to be significantly higher in obese individuals than in lean subjects, moreover, individuals with increased body mass index (BMI) (BMI ≥ 30 kg/m) have fewer DRD2 dopamine receptors. Investigators have also suggested that hormonal mechanism may underline a gender difference in the ability to suppress hunger in relation to this SNP, which may contribute to the greater incidence of obesity in women compared to men. However, authors have pointed out that A1 carriers have difficulty in learning from negative feedback in a reinforcement-learning task and are less efficient at learning to avoid actions that have negative consequences.