Given a question and a context passage, generate the answer having the word or phrase from the context passage. Here, the answer should be a shortest continous span from the passage.

Input: Consider Input: Context: Human erythrocyte spectrin is an antiparallel heterodimer comprised of a 280 kDa alpha subunit and a 246 kDa beta subunit which further associates into tetramers in the red cell membrane cytoskeleton. Lateral association of the flexible rodlike monomers involves a multiple-step process that is initiated by a high affinity association near the actin-binding end of the molecule (dimer nucleation site). In this study, recombinant alpha and beta proteins comprising two or four "spectrin type" motifs with and without adjacent, terminal nonhomologous domains were evaluated for their relative contributions to dimer initiation, and the thermodynamic properties of these heterodimer complexes were measured. Sedimentation equilibrium studies showed that in the absence of the heterologous subunit, individual recombinant proteins formed weak homodimers (K(d) > 0.3 mM). When 2-motif (alpha20-21 and beta1-2) and 4-motif (alpha18-21 and beta1-4) recombinants lacking the terminal nonhomologous domains were paired with the complementary protein, high affinity heterodimers were formed in sedimentation equilibrium analysis. Both the alpha20-21/beta1-2 complex and the alpha20-21EF/betaABD1-2 complex showed stoichiometric binding with similar binding affinities (K(d) approximately 10 nM) using isothermal titration calorimetry. The alpha20-21/beta1-2 complex showed an enthalpy of -10 kcal/mol, while the alpha20-21EF/betaABD1-2 complex showed an enthalpy of -13 kcal/mol. Pull-down assays using alpha spectrin GST fusion proteins showed strong associations between all heterodimer complexes in physiological buffer, but all heterodimer complexes were destabilized by the presence of Triton X-100 and other detergents. Complexes lacking the nonhomologous domains were destabilized to a greater extent than complexes that included the nonhomologous domains. The detergent effect appears to be responsible for the apparent essential role of the nonhomologous domains in prior reports. Taken together, our results indicate that the terminal nonhomologous domains do not contribute to dimer initiation nor are they required for formation of high affinity spectrin heterodimers in physiological buffers. 
 Question: Alpha-spectrin and beta-spectrin subunits form parallel or antiparallel heterodimers?

Output: antiparallel


Input: Consider Input: Context: Recent genome-wide association studies (GWAS) for Caucasians identified several allelic variants associated with increased risk of developing restless legs syndrome (RLS), also known as Willis-Ekbom disease. Although the pathogenic mechanisms of RLS are not entirely understood, it is becoming increasingly evident that many diseases such as RLS can be attributed to an epistasis. The study objectives were to evaluate whether the associations of RLS with all loci determined in previous GWAS for Caucasians can be replicated significantly for the Korean population and to elucidate whether an epistasis plays a role in the pathogenesis of RLS. DNA from 320 patients with RLS and 320 age- and sex-matched controls were genotyped for variants in the RLS loci. A significant association was found for rs3923809 and rs9296249 in BTBD9 (P < 0.0001 and P = 0.001, respectively); the odds ratio (OR) for rs3923809 was 1.61 (P < 0.0001) to 1.88 (P < 0.0001) and the OR for rs9296249 was 1.44 (P = 0.001) to 1.73 (P = 0.002), according to the model of inheritance. The OR for the interaction between rs3923809 in BTBD9 and rs4626664 in PTPRD was 2.05 (P < 0.0001) in the additive model, 1.80 (P = 0.002) in the dominant model and 2.47 (P = 0.004) in the recessive model. There was no significant association between genotypes of all tested single nucleotide polymorphisms and the mean value of serum iron parameters. Our results suggest that the role of BTBD9 in the pathogenesis of restless legs syndrome is more universal across populations than previously reported and more efforts should be focused on the role of epistasis in the genetic architecture of restless legs syndrome. 
 Question: Willis-Ekbom disease is also known as?

Output: restless legs syndrome


Input: Consider Input: Context: Dogmatix is a fictional character, a tiny white terrier dog who belongs to Obelix in the Asterix comics. 
 Question: What show is Dogmatix from?


Output: asterix