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Whole-genome resequencing provides the opportunity to explore the genomic variations and pave way for further functional assays to map the economical trait loci. In this study, we sequenced the genomes of mixed chicken samples from a full-sib family, with feathered and unfeathered legs at an average effective depth of 4.43×, using Illumina Hiseq 2000 instruments. Over 2.1 million nonredundant short indels (1-71 bp) were obtained. Among them, 16,375 common indels that were polymorphic between the comparison groups were revealed for further analysis. The majority of the common differential indels (76.52%) were novel. Follow-up validation assays confirmed that 80% randomly selected indels represented true variations. The indels were annotated based on the chicken genome sequence assembly. As a result, 16,375 indels were found to be located within 2756 annotated genes, with only 33 (0.202%) located in exons. By integrated analysis of the 2756 genes with gene function and known quantitative trait loci, we identified a total of 24 promising candidate genes potentially affecting feathered-leg trait, i.e. FGF1 , FGF4 , FGF10 , FGFR1 , FRZB , WNT1 , WNT3A , WNT11 , PCDH1 , PCDH10 , PCDH19 , SOX3 , BMP2 , NOTCH2 , TGF-β2 , DLX5 , REPS2 , SCN3B , TCF20 , FGF3 , FSTL1 , WNT7B , ELOVL2 and FGF8 . Our findings provide a basis for further study and reveal key genes for feathered-leg trait in chickens.

Fatty acids metabolic products determine meat quality in chickens. Identifying genes associated with fatty acids composition could provide valuable information for the complex genetic networks of genes with underlying variations in fatty acids synthesis. RNA sequencing (RNA-Seq) was conducted to explore the chicken transcriptome from the thigh muscle tissue of 6 Huangshan Black Chickens with 3 extremely high and low phenotypic values for percentage of polyunsaturated fatty acids (PUFAs). In total, we obtained 41,139,108-44,901,729 uniquely mapped reads, which covered 74.15% of the current annotated transcripts including 18964 mRNA transcripts, across all the six thigh muscle tissue samples. Of these, we revealed 274 differentially expressed genes (DEGs) with a highly significant correlation with polyunsaturated fatty acids percentage between the comparison groups based on the ratio of PUFA/SFA. Gene ontology and pathway analysis indicated that the DEGs were enriched in particular biological processes affecting fatty acids metabolism, biosynthesis of unsaturated fatty acids (USFAs), and cell junction-related pathways. Integrated interpretation of differential gene expression and formerly reported quantitative trait loci (QTL) demonstrated that FADS2, DCN, FRZB, OGN, PRKAG3, LHFP, CHCHD10, CYTL1, FBLN5, and ADGRD1 are the most promising candidate genes affecting polyunsaturated fatty acids percentage.