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Background: The variety of indigenous duck germplasm contribute maximum to the poultry industry in India, besides chicken population. In southern part of India, the available duck genetic resource, particularly Arni ducks (comprises of Sanyasi and Keeri ducks) of Tamil Nadu, has its own characteristics with innate potentiality of higher productivity without any input system of management. Genetic characterization and diversity of indigenous duck genetic resources has not been properly studied. In the present study, the genetic diversity of Arni ducks with other indigenous and exotic duck germplasm were analysed with microsatellite markers. Methods: Genomic DNA was isolated from the blood samples of six duck populations. Molecular characterization was carried out with duck specific FAO recommended microsatellite markers. The genotyping of ducks was done based on the size of 4324 PCR amplicons of 23 microsatellite loci, which were subjected to capillary electrophoresis using automatic sequencer. Result: A total of 222 alleles in six duck populations across 23 microsatellite loci with a mean of 9.65±0.95 alleles were found. Kuttanad duck variety had the highest number of alleles (139) followed by Sanyasi (136), Keeri (129), Muscovy (118), Assam (91) and White Pekin (78) ducks. The mean observed number of alleles was 6.04±0.59, 5.91±0.76, 5.61±3.17, 5.13±0.44, 3.96±0.76 and 3.39±0.40 in Kuttanad, Sanyasi, Keeri, Muscovy, Assam and White Pekin ducks respectively. The overall mean polymorphism information content (PIC) values among the six duck populations was 0.6269. In most of the duck populations, the mean PIC value was more than 0.5 except in Assam (0.4815) and White Pekin (0.3725) ducks. The observed heterozygosity was the highest in Keeri ducks (0.5217) and lowest in White Pekin ducks (0.2766), while, the mean expected heterozygosity was the highest in Sanyasi (0.5628) and lowest in White Pekin (0.4038) ducks. The variations in the observed and expected number of alleles, differences in PIC of various microsatellite loci might be attributed to the genetic variability of the duck populations, number and type of microsatellite primers utilised for analysis and the genetic diversity of the duck breeds under study. Higher FST value indicates the substantial degree of breed differentiation among the studied duck populations. [ABSTRACT FROM AUTHOR]

Indigenous ducks play a vital role in sustainable livelihood of the poor duck farmers. In Tamil Nadu, two popular indigenous duck varieties viz., Sanyasi and Keeri are being reared traditionally by the duck farmers under nomadic system. In the same way, Kuttanad ducks are popular in Kerala and Assam ducks are popular in Assam. The present research work was undertaken to study the genetic distance between and within the indigenous ducks and exotic duck breeds by using duck specific microsatellite markers. From the blood samples the genomic DNA was isolated and characterized genetically. With the molecular data, dendrogram was constructed. This revealed that, Keeri, Sanyasi, Kuttanad and Assam ducks formed the first group with White Pekin in the second group and Muscovy in the third cluster. Among the Indian duck varieties, Keeri and Sanyasi ducks of Tamil Nadu were found to be closer to each other as indicated by the genetic distance value of 0.11. However, within this group, 26.33 and 29.87 per cent of differentiation were noticed between Assam and Sanyasi and Assam and Keeri ducks respectively. Higher genetic distance value of 0.92 (92 per cent) was observed between two exotic ducks. Based on the genetic distance and genetic diversity between the indigenous ducks, the duck varieties of Tamil Nadu, Kerala and Assam may be classified as distinct breeds. [ABSTRACT FROM AUTHOR]