Objective: A set of microsatellite markers with high polymorphism from Tsaiya duck were used for the genetic monitoring and genetic structure analysis of Brown and White Tsaiya duck populations in Taiwan.Methods: The synthetic short tandem repeated probes were used to isolate new microsatellite markers from the genomic DNA of Tsaiya ducks. Eight populations, a total of 566 samples, sourced from Ilan Branch, Livestock Research Institute were genotyped through novel and known markers. The population genetic variables were calculated using optional programs in order to describe and monitor the genetic variability and the genetic structures of these Tsaiya duck populations.Results: In total 24 primer pairs, including 17 novel microsatellite loci from this study and seven previously known loci, were constructed for the detection of genetic variations in duck populations. The average values for the allele number, the effective number of alleles, the observed heterozygosity, the expected heterozygosity, and the polymorphism information content were 11.29, 5.370, 0.591, 0.746, and 0.708, respectively. The results of analysis of molecular variance and principal component analysis indicated a contracting Brown Tsaiya duck cluster and a spreading White Tsaiya duck cluster. The Brown Tsaiya ducks and the White Tsaiya ducks with Pekin ducks were just split to six clusters and three clusters when K was set equal to 6 and 3 in the Bayesian cluster analysis. The individual phylogenetic tree revealed eight taxa, and each individual was assigned to its own population.Conclusion: According to our study, the 24 novel microsatellite markers exhibited a high capacity to analyze relationships of inter- and intra-population in those populations with a relatively limited degree of genetic diversity. We suggest that duck farms in Taiwan could use the new (novel) microsatellite set to monitor the genetic characteristics and structures of their Tsaiya duck populations at various intervals in order to ensure quality breeding and conservation strategies.

Breeding and genetics Full-length research article Effects of melanocortin 1 receptor (MC1R) gene polymorphisms on plumage color in mule ducks ABSTRACT-The objective of the present study was to investigate the effect of single nucleotide polymorphism (SNP) of the melanocortin 1 receptor (MC1R) gene on plumage coloration in mule ducks. PCR-high-resolution melting analysis (PCR-HRM) and DNA sequencing were used to identify the SNP variability of the MC1R gene in white common ducks. Three non-synonymous SNP (MC1R gene exon 1, c.52G>A, c.376G>A, and c.409G>A) were identified in white Tsaiya ducks. Mating test (white Tsaiya ducks × white Muscovy drakes) in combination with polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was performed to investigate the effect of non-synonymous SNP of different maternal lines on plumage coloration in mule ducks. Genotyping results from 58 white Tsaiya ducks revealed the significant associations between genetic variations (c.52G>A, c.376A>G, and c.409G>A) and plumage color in two maternal populations. After genotyping of 266 mule ducks, these three non-synonymous SNP identified in white Tsaiya ducks were significantly associated with plumage color of mule ducks. Therefore, the polymorphisms of MC1R gene at c.52G>A, c.376A>G, and c.409G>A in white Tsaiya duck could be used in marker-assisted selection to improve the plumage color of mule ducks.

Objective: Few studies have genetically monitored chickens over time, and no research has been conducted on ducks. To ensure the sustainable management of key duck breeds, we used microsatellite markers to monitor Brown Tsaiya ducks over time genetically. Methods:The second, fourth, sixth to eighth generations of the Brown Tsaiya duck selected feeding efficiency and control lines were included in this study to investigate the genetic variations, effective population size, population structure and the differentiation between populations over time with 11 microsatellite markers derived from Brown Tsaiya duck. Results:The results showed there were a slight decrease in the genetic variations and an increase in within-population inbreeding coefficient (FIS) in both line, but no consistent increase in FIS was observed in eacheither line. The effective population size in the second and eighth generations was 27.2 for the selected line and 23.9 for the control line. The change in allele richness (AR) showed a downward trend over time, and the selected line is slightly lower than the control line in each generation. The number of private alleles (Np) in the selected line were higher than in the control line. Moderate differentiation was observed between the second and eighth generations in the selected line (FST = 0.0510) and the control line (FST = 0.0606). Overall, differentiation tended to increase with each generation, but genetic variation and structure did not change considerably after six generations in the two lines. Conclusion:This study will as a reference for poultry conservation and help to implement cross-generation genetic monitoring and breeding plans in other duck breeds or lines to promote sustainable management.