Lethal autosomal recessive JEB mutation in draft horse breeds of Russia and the USA: pathological and genealogical analysis of risks to closed population welfare and the bioethics of gene pool preservation

The article examines the genetic and bioethical aspects of the lethal autosomal recessive mutation Junctional Epidermolysis Bullosa (JEB), observed in populations of draft horse breeds in Russia and the United States that historically share a common influence of European (Belgian) bloodlines. Based on a comparative analysis of the Soviet Draft Horse and the American Cream Draft Horse, the study explores the latent threat to the preservation of valuable breeding lines and the impact of JEB-associated alleles on the integrity of the breeding nucleus. It is noted that, under conditions of small population size and limited genetic diversity, the absence of a targeted program for systematic genetic testing and optimized breeding management in Russian horse breeding contributes to the deposition and genetic drift of abnormal alleles within the breed, whereas foreign breeding programs actively employ preventive genetic screening practices. The conducted study emphasizes the need to promote the principles of responsible breeding and to implement genetic monitoring tools as a priority component of effective breeding management - an approach of direct importance for the sustainable welfare of national breeds and alignment with international standards of animal welfare and bioethics.