Positional cloning of Bst. (A) Recombination data localizing Bst to a 0.5 cM interval on mouse chromosome 16 (shaded in red) and excluding Opa1 and Hes1. Bst and microsatellite alleles transmitted by F1 parents are indicated together with the number of N2 progeny in each class. The 135 N2 mice typed with the extended marker set (left) are included in the total (right). □, CAST/Ei; ■, C57BLKS. (B) Physical map of critical Bst region derived from Ensembl mouse genome database (3.35 Mb, v. 4.1.1). The map shows informative microsatellite markers, candidate transcription units and relevant BAC clones (blue). The nonrecombinant interval maps within cytogenetic band B4, spans 1.5 Mb (green arrows) and includes Rpl24 (red).