Table 2.

Cosmid lengths

Chromosome 9 probes	Length ± SD, μm	Chromosome 21 probes	Length ± SD, μm
108H11	16.9  ±  1.6	F08132	20.4  ±  1.8
212F2	20.5  ±  0.6	H0973	15.8  ±  0.9
269C11	16.6  ±  1.4	A03115	14.6  ±  1.1
20D5	13.6  ±  1.3	F0812	21.2  ±  0.8
149B8	21.7  ±  0.4	F02103	16.1  ±  0.9
Sum of probes	89.3  ±  1.2	Sum of probes	88.1  ±  1.2
Contig	80.7  ±  3.8

Cosmid probe lengths measured by molecular combing. Cosmids were combed on individual surfaces from a batch whose stretching parameter was verified by using a test lambda DNA. Approimately 100 molecules of each cosmid were measured and their respective sizes were determined by fitting the main peak of the histogram to a Gaussian distribution. The chromosome 9 cosmid contig length was obtained by direct end-to-end measurements made on the intact contig hybridization signals.