A Microsatellite Genetic Linkage Map of Human Chromosome 18
R.E. Straub, M.C. Speer, Y. Luo, K. Rojas, J. Overhauser,
J. Ott, T.C. Gilliam
Genomics , 15(1),48--56 (1993 Jan)
Abstract
We isolated nine new microsatellite markers from chromosome 18 and
further characterized and mapped eight microsatellites developed in
other laboratories. We have constructed a framework linkage map of
chromosome 18 that includes 14 microsatellite markers (12
dinucleotide and 2 tetranucleotide) and 2 RFLP markers. Cytogenetic
localization for the microsatellites was performed by PCR
amplification of 18 somatic cell hybrids containing different
deletions of chromosome 18. Twelve of the microsatellites and one of
the RFLPs have heterozygosites greater than 70%. The average
heterozygosity of the markers included in the map is 72%. In
addition, we have made provisional placements of 3 more
microsatellite markers and 2 more RFLP markers. The map lengths (in
Kosambi centimorgans) are as follows: sex-averaged, 109.3 cM; male,
72.4 cM; female, 161.2 cM. The average distance between markers in
the sex-averaged map is 7.3 cM, and the largest gap between markers
is 16.7 cM. Analysis of the data for differences in the female:male
map distance ratio revealed significant evidence for a constant
difference in the ratio (chi 2 = 32.25; df = 1; P < 0.001; ratio =
2.5:1). Furthermore, there was significant evidence in favor of a
variable female:male map distance ratio across the chromosome
compared to a constant distance ratio (chi 2 = 27.78; df = 14; P =
0.015). To facilitate their use in genomic screening for disease
genes, all of the microsatellite markers used here can be amplified
under standard PCR conditions, and most can be used in duplex PCR
reactions.
