YAC-contig and STS map representing an 8-Mb segment of human chromosome 6p21.3–p22 between the distal end of the MHC and D6S276. Forty-three YACs were tested by PCR for the presence or absence of 86 STSs, indicated along the top. STSs in boldface type have not been described previously. STSs marked with a solid circle (•) above the STS name are included in the bacterial clone-based STS content map in Fig. 2. The STSs were ordered so as to minimize the number of YACs with a non contiguous complement of STSs. Groups of STSs not uniquely ordered based on the STS content of the YACs are indicated by solid bars below the STS names. Triple bars indicate adjacent STS pairs connected by less than two independent YACs. YACs are named by the prefix y followed by their respective library address. YACs are depicted as shaded horizontal bars, whose lengths represent their STS content rather than their physical length. YAC sizes (in Mb) are indicated in the second column. Columns 3 and 4 contain information regarding clone chimerism. (N, column 3) STSs from both YAC-insert ends can be amplified from chromosome 6. (Y, column 3) YACs from which at least one insert-end STS is not present on chromosome 6. The result of a search of the MIT/Whitehead database for hits by STSs from chromosomes other than chromosome 6 is reported in column 4, with the numbers referring to the respective chromosome. Outlined YACs constitute a minimal set of nine clones linking HLA-F near the distal end of the MHC to D6S276. The presence of an STS in a YAC is indicated by a + or by a solid square (▪), the latter marking a clone-end STS at the end of the YAC from which it was derived. The absence of an STS in a YAC is indicated by a −. D6S1016 gives rise to PCR products that fall into a large and a small size class, the presence of which are denoted by ▵ and ▿, respectively. With the exception of y906h11, all YACs have been tested for all STSs.
