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Chromosomal fragile site expression in dogs: I. Breed specific differences.
D M Stone1, P B Jacky, D D Hancock
1Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164-7040.
American Journal of Medical Genetics
|August 1, 1991
Summary
Canine lymphocytes exhibit fragile sites on both autosomal and X chromosomes. Aphidicolin-induced fragile site expression was significantly higher than folate-sensitive fragile site expression in dogs.
Area of Science:
- Cytogenetics
- Canine Genetics
- Molecular Biology
Background:
- Fragile sites are specific points on chromosomes prone to breakage.
- Understanding fragile sites in domestic animals like dogs can provide insights into genome stability.
- Previous studies have characterized fragile sites in various species, but canine-specific data is limited.
Purpose of the Study:
- To investigate the presence and characteristics of folate-sensitive and aphidicolin-inducible fragile sites in canine lymphocytes.
- To compare the frequency of fragile site expression between different canine breeds (Doberman Pinscher and Boxer).
- To identify the chromosomal locations of fragile sites in dogs and compare them to human fragile sites.
Main Methods:
- Peripheral blood lymphocytes from Doberman Pinscher and Boxer dogs were cultured.
- Cells were treated with folate/thymidine depletion to induce folate-sensitive fragile sites.
- Cells were also treated with aphidicolin to induce aphidicolin-inducible fragile sites.
- Chromosomal analysis was performed to identify and map fragile sites.
Main Results:
- Both autosomal and X chromosomal fragile sites were observed in canine cells.
- Aphidicolin-inducible fragile site expression was significantly more frequent than folate-sensitive fragile site expression (P < 0.05).
- Boxer dogs showed a higher percentage of aphidicolin-inducible fragile sites (66.67%) compared to Doberman Pinschers (21.10%).
- Age was positively correlated with folate-sensitive fragile site expression in Boxers but not Doberman Pinschers.
- Three fragile sites on the dog X chromosome showed homology with human X chromosomal fragile sites.
- Two specific autosomal fragile sites were identified on chromosomes 1 and 8.
Conclusions:
- Canine lymphocytes possess both folate-sensitive and aphidicolin-inducible fragile sites.
- Aphidicolin is a more potent inducer of fragile site expression in canine lymphocytes compared to folate depletion.
- Breed and age can influence fragile site expression patterns in dogs.
- Identified fragile sites on the canine X chromosome suggest conserved chromosomal organization with humans, offering potential for comparative genomics studies.