Discipline: Veterinary Medicine
DNA barcodes (i.e. cytochrome c oxidase subunit I or COI in the mitochondrial genome) obtained from fourteen (14) domestic goat and sheep breeds (Subfamily Caprinae) in the Philippines were analyzed using the Neighbour-Joining method based on Kimura 2-parameter model in MEGA5. Mean genetic diversity in COI sequences was higher among goat breeds (62.6%) than sheep breeds (32.9%). Average genetic distance between goats and sheep was 0.831 ± 0.042 units.
Based on 589 COI positions, average genetic distance among native goat breeds (i.e. d = 0.286 ± 0.020) was higher than among pure (exotic) breeds (i.e. d = 0.111 ± 0.012). Average genetic distance between goat groups was 0.911 ± 0.062 units, suggesting that the origin and evolution of native goat breeds sampled from different islands in the Philippines were independent of exotic breeds such as Anglo Nubian, Boer and Saanen. Based on 674 COI positions, average genetic distance among wool-type breeds (i.e. d = 0.378 ± 0.019) was higher than among hair-type breeds (i.e. d = 0.250 ± 0.016). Average genetic distance between sheep groups was 0.312 ± 0.013 units. The Philippine sheep is genetically closer to Merino (d=0.161) than recently imported wool-type breeds (Dorper, Dorset, and Suffolk) and hair-type breeds (Damara, Katahdin, and St. Croix). Our analyses indicated that DNA barcodes can be effective to identify and differentiate between breeds within goat and sheep species. Further analysis is required to clarify large COI differences between breeds of goats.
DNA barcode analysis is recommended as a quick screening, reliable, cost-effective, and accessible tool for the identification, assessment, and cataloguing of domestic goats and sheep biodiversity in the country. It could also provide useful information to support decisions on the genetic improvement and conservation of important breeds of small ruminants.