Polymorphic markers for the arylsulfatase A gene reveal a greatly expandedmeiotic map for the human 22q telomeric region

Two microsatellite markers, D22S1743 and D22S1744, were developed for the a rylsulfatase A (ARSA) region of chromosome 22q. Linkage analysis for 171 fa milies, using nine reference markers covering all of 22q, placed these new markers 2.0 Kosambi cM distal to D22S526, making them more distal than any microsatellite markers currently on the Genethon or Marshfield linkage maps . Recombination between proximal markers D22S270/D22S683 and D22S446/D22S31 1 exhibited increased rates of female meiotic recombination compared to mal e recombination (P < 0.01). In contrast, the region encompassing sJCW16, D2 2S526, D22S1743, and D22S1744 exhibited relatively greater recombination in males (1.1 cM for females and 7.5 cM for males; chi(2); P < 0.005). These four distal markers lie in a region of hyperrecombination having a sex-aver aged recombination ratio of between 8.3 (D22S1843/D22S1744) and 12 cM (sJCW 16/D22S526) per megabase. (C) 2000 Academic Press.