Karyological Data About the Bulgarian Native Dog Breed “Karakachan Dog”

ABSTRACT

The Karakachan is a mountain sheep dog belonging to a rare livestock protection breed. The Karakachan dog is a breed originated in Bulgaria and is a descendant of the dogs bred by the Thracian nomadic shepherds.

The aim of the present investigation is to approbate and optimize an appropriate methodology to investigate the dog's chromosome set without disturbing the animals vital functioning. For this purpose bone marrow cells dragged out of the sternum of male and female individuals aging between 3.5 to 15 years were used. The yield material was cultivated 24 hours at 37°C in RPMI medium with 10% of FBS and 2 mM Lglutamine.

Metaphase plates for karyological analysis were obtained by preliminary treatment of the express cell culture with colchicine (0.4 mg/ml culture medium), incubated with 0.075 M potassium chloride at 37°C, fixed in cold 1:3 glacial acetic acid: methanol and stained in 5 % Giemsa solution (Sigma Diagnostic).

The chromosome set of the karakachan dog consists of 78 chromosomes, 38 pairs of which are acrocentric autosomes and one pair of sex chromosomes. In some of metaphase plates structural chromosome aberrations were observed—breaks and fragments. Polyploid cells were also counted. These chromosome damages could be due either to endogenous factors connected to the animals' age or to the exogenous influence of the environmental genotoxicants. The optimized protocol could be easily applied to any other dog breed and in wolfs for karyological studies.

Keywords:

• chromosome
• chromosome aberrations
• dog karyotype
• karakachan dog