Construction and integration of genome maps of domestic dog chromosomes X and 1

Spriggs, Helen Florence (2000). Construction and integration of genome maps of domestic dog chromosomes X and 1. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000ff95

Abstract

This thesis describes an integrated approach to mapping dog chromosomes X and 1. Small-insert libraries in pBluescript were constructed from flow-sorted chromosomes X and 1 from which, microsatellite-containing clones were identified and sequenced. Database searches identified homologies between X derived clones and genes previously characterised in other species.

The physical locations of the microsatellite-containing clones were mapped using fluorescence in situ hybridisation (FISH), confirming that the clone libraries were highly enriched for their respective chromosomes (91 % for chromosome X, 86% for chromosome 1). These libraries, and the mapped clones, represent a valuable resource previously unavailable in dog genomics.

PCR primers were designed from sequences from these libraries, flanking microsatellites for both meiotic linkage and radiation hybrid mapping, and flanking other seqyences for radiation hybrid mapping alone. Primers were also designed from other available sequences mapping to dog chromosomes X and 1.

Chromosome X-derived microsatellites were typed on families from the Cornell reference pedigree, adding 17 markers. Chromosome X and 1 markers were typed using the T72 whole genome radiation hybrid panel (WG-RH). A total of 37 chromosome X-derived markers were mapped to eight WG-RH linkage groups and 18 chromosome 1-derived markers were mapped to five WG-RH linkage groups.

Use of a common pool of chromosome-specific markers in three distinct mapping methods facilitates integration, producing unified maps for these chromosomes. The FISH and WG-RH data are complementary, the former giving long-range data and absolute locations, the latter providing local relative ordering. When supplemented with the genetic data, integration with pre-existing maps of chromosome X is possible.

The integrated maps reveal strongly conserved synteny between canine and human X chromosomes. The pseudoautosomal region has been further characterised, the putative or actual locations of nine clinically relevant genes have been suggested, and the canine DMD region better defined.