Ivan Majzlík

Genomic analysis of resistance/susceptibility to melanoma in Old Kladruber greying horses

Melanoma is a common disease occurring in many horse breeds. As in all tumors its nature is complex, and specific genes were shown to be involved in the mechanisms of disease in humans as well as in various animal species (1). Grey horses, regardless of the breed, show high incidence of dermal melanomas. A mutation within the syntaxin 17 gene responsible for greying in horses was shown to be associated with occurrence of melanoma in grey horses but the association observed did not explain completely the variation observed (2). Other factors influencing the formation of melanoma thus must be involved. In this context, immunity-related genes can be considered as functional candidate genes. Old Kladruber grey horses were selected as a model for analyzing associations between microsatellite and candidate gene polymorphic markers and the presence of melanoma. Genetic diversity of this old, small, isolated and partially inbred population was characterized previously.

Characterization of greying, melanoma, and vitiligo quantitative inheritance in Old Kladruber horses

The paper deals with the greying process, melanoma, and vitiligo depigmentation occurrence in Old Kladruber horses (OKH). The study includes 376 animals of both sexes at the age of 1-25 years. The evaluation was performed repeatedly during 4 consecutive years. The greying status was measured spectro - photometrically on four body parts using L*a*b* colour system. Melanoma and vitiligo were detected visu - ally and by palpation in all the animals and classified using 5 (3) grade scale. The GLM procedure of SAS package was used to examine the influence of the effects of line, age, sex, stud, and year of evaluation. The GLM analysis confirmed a significant impact of age on greying. Parameter L* showed progressive increase until 10 years of age when all horses reached final grey level. Subsequent analyses suggested the influence of sex, i.e. a notably higher level of greying in mares. The incidence of melanoma was confirmed. Melanoma in OKH most frequently occurs on the bottom of the tail or at the anal and perineal area. Probably only benign forms of melanoma have been detected. The global occurrence of melanoma in OKH (ca. 13%) is substantially lower than in Lipizzan and Camargue horses. Overall incidence of melanoma in horses at the age of 15 and older reached 68%. Genetic parameters were estimated for melanoma grade, grey level, and vitiligo. Greying is strictly influenced by age ( h 2 = 0.52 ± 0.07). Prevalence of melanoma progresses with age ( h 2 = 0.07 ± 0.04). Vitiligos of both facial and anal parts are influenced by the effects studied ( h 2 = 0.20 ± 0.05 and 0.34 ± 0.06 for vitiligo A and vitiligo F, respectively).

Leptin Promoter Region Genotype Frequencies and Its Variability in the Czech Fleckvieh Cattle

Abstract To investigate the differences between the lineages of the Czech Fleckvieh cattle in Leptin promoter SNP C963T, 695 Czech Fleckvieh cows (650 from production herds and 45 from the Genetic Resources Program (GR)) were examined using PCR-RFLP. The C and T alleles of Leptin promoter were observed with a predominance of C allele in both groups. The most frequent genotypes were CC (63%) in production herds and CT (48%) in the GR population. The present study describes, for the first time, the genetic differences in production herds and GR population in Leptin promoter C963T SNP. Variation within the Czech Fleckvieh population was observed and resulted in an advantage to the GR population. Results presented herein emphasized the importance of the GR program as a reservoir of genetic diversity for indigenous breeds.