Characteristics of the complete mitochondrial genome of Douhua chicken (Gallus gallus) and phylogenetic considerations.

Douhua chicken is a unique local breed from Anhui Province, China. This study aimed to illustrate the Douhua chicken mitogenome and clarify its phylogenetic status by sequencing and annotating the complete mitochondrial genome using high-throughput sequencing and primer walking. Phylogenetic analysis through the Kimura 2-parameter model indicated the maternal origin of Douhua chicken. The results revealed that the mitochondrial genome is a closed circular molecule (16,785 bp) that consists of 13 protein-coding genes, 22 transfer RNA (tRNA) coding genes, two ribosomal RNA (rRNA) coding genes, and a control region. The base composition of the Douhua chicken mitogenome contains 30.3% A, 23.7% T, 32.5% C, and 13.5% G, and the haplotype and nucleotide diversity values are 0.829 (Hd) and 0.00441 (Pi), respectively. Furthermore, 10 haplotypes of D-loop sequences among 60 Douhua chickens were identified and distributed into four haplogroups (A, C, D, and E). Overall, the result of the present study indicates that Douhua chicken may have originated from Gallus gallus, and this process was influenced by Gallus gallus spadiceus, Gallus gallus murghi, and Gallus gallus bankiva. This study provides novel mitogenome data to support further phylogenetic and taxonomic studies on Douhua chicken. Additionally, the findings of this study will provide deeper insights for identifying the genetic relationships among populations and tracing maternal origins based on phylogenetic considerations for use in studies on the geographic conservation, utilization, and molecular genetics of poultry species.

In the modern poultry industry, resources of native varieties have become major aspects. Douhua chicken is a medium-sized, slow-growing, and white-feathered local breed that represents a popular local chicken breed in Anhui Province, China. This breed is adaptable and exhibits important production traits and a stable inheritable characteristics, such as delicious meat and stable egg-laying performance. The present study aimed to provide a better understanding of the germplasm characteristics and phylogenetic relationships of Douhua chicken by analyzing its complete mitochondrial genome sequence and a describing its genomic composition, nucleotide composition, and gene structure. The present study provides theoretical support for the protection, development, and utilization of Douhua chicken resources. Additionally, this study provides new mitochondrial genome data to support further phylogenetic and taxonomic studies conducted on Douhua chicken.

Mitochondrial genome and phylogenetic analysis of Chaohu duck.

A complete mitochondrial genome sequence is important for the accurate determination of phylogenetic relationships. Chaohu duck is a dominant native breed in Anhui Province, China. We aimed to ascertain the complete mitochondrial genome sequence of Chaohu duck via high-throughput sequencing and primer walking. Phylogenetic analysis of Chaohu duck was performed following Kimura 2-parameter model. The total length of the mitogenome was 16,597 bp, and comprised 29.2 %A, 22.2 % T, 32.8 % C, and 15.8 % G. It included 2 ribosomal RNA genes, 13 protein-coding genes, 22 transfer RNA genes and a control region (D-loop). Furthermore, the haplotype diversity and nucleotide diversity values were 0.9028(Hd) and 0.01162(Pi) respectively. This indicates that Chaohu duck has high population diversity. Twenty-two haplotypes were identified in sixty Chaohu ducks which were divided into two haplogroups. Therefore, we inferred that Chaohu duck may originate from Anas platyrhynchos, and was influenced by Anas poecilorhyncha during evolution. Our results provide mitochondrial genome information for further studies on Chaohu ducks and lays a foundation for germplasm resources conservation.