Object and tasks of work: 1. Analyse and summarize literature about horse coat color and it genetic background. 2. Perform phenotypical analysis of Lithuanian Heavy Darught horse coat color polymorphism. 3. Introduce horse MC1R gene research methodology at K. Janušauskas Laboratory of Animal Genetics, LVA. 4. Investigate MC1R gene polymorphism and distribution of different alleles at Lithuanian heavy draught by PCR-RFLP method. 5. Determine correlation between restriction fragment lenght polymorphism (RFLP) in MC1R gene and horse bay coat color polymorhism. Research methodology: 1. DNA extraction from hair roots. 2. PCR to amplify MC1R gene. 3. RFLP method-MC1R – enzyme Tag I. 3. Electrophoresis in agarose gel. 4. Staining with Etidium bromide. 5. Genotyping. 6. Stasitical analysis of data. Results and conclutions: The following DNA restriction fragments were obtained for the MC1R – Tag I polymorphism: PCR product - 460 bp; genotypes E/E; ea/ea – 460 bp; genotypes e/e – 275 bp; 185 bp; genotypes E/e; e/ea – 460 bp; 275 bp; 185 bp. After phenotypical investigation of coat color from 32 Lithuanian Heavy draught horses following variation have been found: light bay, bay, dark bay, roan and chesnut. Light bay horses with different intensivity of coat color comprised 84,4 %. From total investigated animals 34.4 % had e/e genotype, E/e – 12.5 %, e/ea - 50 % and E/E genotype – 3.1 %. Two different genotypes e/e (40.7 %) and e/ea (59.3) were found among bay color horses... [to full text]