Long-range physical mapping around the human steroid sulfatase locus.

Area of Science:

• Genetics
• Molecular Biology
• Human Genetics

Background:

• The steroid sulfatase (STS) gene is located on the human X chromosome.
• Understanding the physical organization of genes on the X chromosome is crucial for genetic research and disease gene mapping.

Purpose of the Study:

• To generate high-resolution physical maps of the X chromosome region containing the STS locus.
• To establish the physical linkage and order of known markers relative to the STS locus.
• To investigate the genetic basis of X-linked ichthyosis and identify potential locations for the Kallmann syndrome gene.

Main Methods:

• Pulsed-field gel electrophoresis (PFGE) was employed to analyze large DNA fragments.
• Restriction site mapping was performed on DNA from a normal male and a mouse-human hybrid cell line.
• DNA probes were used to define physical linkage between the STS locus and other genetic markers.

Main Results:

• Physical maps spanning approximately 4.3 Mb (normal male) and 3.2 Mb (hybrid cell line) were generated.
• The order of markers was established as telomere--(STS, DYS74)--DXS237--DXS278--DXS143--centromere.
• A 180 kb DNA deletion was identified in an individual with X-linked ichthyosis.
• The distance between the STS locus and the pseudoautosomal region was estimated to be at least 4 Mb.

Conclusions:

• High-resolution physical mapping of the X chromosome STS region was achieved.
• The study identified a DNA deletion associated with X-linked ichthyosis.
• The findings provide insights into gene order and distances on the X chromosome, aiding in the localization of other genetic disorders.