Abstract
Sichuan white goose (SCW) is one of the famous indigenous breeds in China. It is the first time that the complete mitochondrial genome sequence of the SCW has been reported. The total length of the mtDNA is 16,741 bp. It contains the typical structure, including 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes, and 1 non-coding control region (D-loop region). The overall composition of the mtDNA was estimated to be 30.27% for A, 22.62% for T, 32.09% for C, and 15.02% for G. Phylogenetic analyses using N-J computational algorithms showed that the analyzed 18 Anseriform species are divided into four major clades: Anatinae, Anserinae, Dendrocygninae and Anseranatidae. In addition, our work confirmed that SCW has a close genetic relationship with Anser albifrons. This work will provide an important dataset for studying the genetic mechanism of goose in China.
Sichuan white goose (SCW) is one of the famous indigenous breeds and an important protected breed of goose in China, which has been bred in Sichuan province for hundreds of years. The features of SCW is high egg productivity, good growth performance, and meat quality (Zhang et al. Citation2018). In this study, we newly determined the complete mitochondrial genome of SCW, and the adult individuals of SCW were collected from its originally breeding farm in Nanxi district (28.85 N and 104.98 E), Sichuan province, China, on August 2018. The specimens were stored at −80 °C in our laboratory (Research Department of Animal Nutrition and Poultry, Hunan Institute of Animal and Veterinary Science). Total genomic DNA was extracted from the thigh muscle of a single individual using the EasyPure Kit of Genomic DNA (Transgen Biotech, Beijing, China). Whole mitochondrial genome was amplified with 13 pairs of primers and sequenced using BioSune Biotech (Shanghai, China). DNA sequence was analyzed using DNAStar.Lasergene.v7.1 software (Madison, WI), tRNA Scan-SE1.21 software (Lowe and Eddy Citation1997), and DOGMA software (Wyman et al. Citation2004).
The total length of the mtDNA is 16,741 bp. It contains the typical structure, including 22 transfer RNA genes, 2 ribosomal RNA genes, 13 protein-coding genes, and 1 non-coding control region (D-loop region) (GenBank accession No. MK133022). The overall composition of the mtDNA was estimated to be 30.27% for A, 22.62% for T, 32.09% for C, and 15.02% for G. The COX1, COX2 and ND5 initiation codon is GTG, and the rest of the proteins are ATG. All these genes have 16 spaces and 8 overlaps both in the length of 1–10 bp. These genes had five types of termination codons, including TAA, TAG, AGG, AGA and an incomplete termination codon ‘‘T––’’. The incomplete codon ‘‘T––’’ is the 5' terminal of the adjacent gene (Anderson et al. Citation1981). Among 13 protein-coding genes, the longest one was ND5 gene (1818 bp) which was located between the tRNALeu and Cytb, and the shortest one was ATPase8 gene (168 bp) which was located between the tRNALys and ATPase6.
Phylogenetic analysis was performed using the complete mitochondrial DNA sequences of 18 Anseriformes. Each of the sequence dataset was aligned by ClustalX (Thompson et al. Citation1997) and analyzed by neighbor-joining (N-J) in MEGA 4.0 (Tamura et al. Citation2007), and bootstrap analysis was performed with 100 replications. An N-J tree showed that the analyzed species are divided into four major clades (). Anatinae makes up the first lineage, which is sister to the second group, Anserinae; Dendrocygninae forms the third group and is sister to Anserinae and Anatinae. The lineage consisting of these three groups in turn is sister to the fourth clade, Anseranatidae. In addition, our work confirmed that SCW has a close genetic relationship with Anser albifrons. This work will provide an important dataset for studying the genetic mechanism of goose in China.
Figure 1. Phylogenetic analysis based on complete mitochondrial genome sequences. An N-J tree was built based on the phylogenetic analysis of 18 Anseriform species’ complete mitochondrial genomes. The mitochondrial genome sequences of the Anseriform species were obtained from the GenBank databases (Accession numbers are marked in the figure). SCW: Sichuan white goose.
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No potential conflict of interest was reported by the authors.
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References
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