Date of Award:

1995

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Animal, Dairy, and Veterinary Sciences

Abstract

Genome maps provide information used to identify economic trait loci and loci proximal to genes affecting economically important traits. This research contributes to the development of the ovine genome map by establishing ovine tissue culture techniques and fluorescent in situ hybridization techniques in this laboratory. In addition, a karyotype for sheep affected with spider lamb syndrome was developed. Ovine tissue culture techniques were established using fibroblasts grown from primary explants of sheep and modified cytogenetic procedures. Metaphase chromosomes were obtained from the fibroblast cultures and used for fluorescent in situ hybridization and for banding procedures to develop the spider lamb karyotype. Fluorescent in situ hybridization procedures were established by hybridizing a fluorescent-labeled probe to fixed ovine chromosome spreads. The probe was a bacterial artificial chromosome clone containing the bovine 3-β-hydroxy-5-ene steroid dehydrogenase gene. In this study, the probe hybridized to ovine chromosome 1. This chromosomal location was supported by the previous hybridization of the probe to bovine chromosome 3, which has a high level of homology with ovine chromosome 1. The final objective of this study was to determine whether a chromosomal abnormality is the cause of spider lamb syndrome, a fatal autosomal recessive genetic disease in North American black-faced breeds of sheep. A fibroblast cell line was produced from a four-week-old male homozygous spider lamb. Chromosomes were banded with trypsin using standard structural banding techniques. The lamb had a normal diploid chromosomes, 23 pairs of autosomal acrocentrics, and a large acrocentric X and a minute biarmed Y chromosome. G-band analysis of all chromosomes within the karyotype did not reveal any abnormality that was attributable to spider lamb syndrome.

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