YAC/STS map of the Xq21 XY homology region. (a) Markers, including X-specific markers (DXS1217, DXS214, and DXS3) and XY homologous markers corresponding to sY markers shown below. (b) Megabase scale. (c) Brackets show corresponding regions of homology on the Y chromosome, including those that are Yp proximal (represented by asterisks in Figs. 1 and 3) and Yp distal (represented by arrows in Figs. 1 and 3). (d) Differentially shaded bar represents X-specific regions (light shading) and XY homologous regions (dark shading). (e) Order of markers, identified by common names, from centromeric to telomeric. Markers shown as a number followed by an L or R identify YAC-end STSs; the number is the yWXD Washington University database accession number of the YAC; L or R indicates the left or right end of the YAC. XSTS0460 is a random X-specific marker. (f) YACs and STS content. YACs are drawn to scale and are identified by a yWXD number followed by either a letter identifying the library of origin (E or F libraries) or the complete library location [(I) ICI library; (M) CEPH mega-YAC library]. (○) The origin of the YAC-end STSs; (•) STS content in the YACs. Several STSs were spaced too closely to be discriminated from neighboring STSs and have not been illustrated on the map. These include sY30, sY31, sY33, sY34, sY36, and sY37, which have been placed in general numeric order in relation to the other sY markers. The marker sY25 could not be placed accurately on the map because of weak signals from X-specific templates but is placed tentatively between sY24 and sY26 (see text). The size of the X-specific region at DXS214 is unknown and is not necessarily drawn to scale.
