Characterization of the Mitochondrial Genome of Cambaroides schrenckii (Astacidea: Cambaridae) and Its Phylogenetic Implications.

BACKGROUND

Cambaroides schrenckii is an endangered freshwater crayfish in China, belonging to the genus Cambaroides, that can act as a complementary host for paragonimus. The objective of this study was to examine the complete mitochondrial genome characteristics and their evolutionary relationships within the Astacidea.

METHODS

The analysis of gene rearrangements and evolutionary relationships was conducted through the sequencing of the mitochondrial genome of C. schrenckii.

RESULTS

C. schrenckii mitochondrial genome length was 15,572, comprising thirteen PCGs, two rRNAs, 22 tRNAs, and one d-loop region of C. schrenckii. The mitochondrial genome of C. schrenckii exhibits an A + T content of 69.61% and a G + C content of 30.39%. Among the thirteen PCGs, cytb, nad3, and nad6 have a start codon of ATT, while the other ten PCGs have ATC, ATA, and ATG start codons. All 22 tRNA genes displayed a typical cloverleaf secondary structure. Gene rearrangement analysis showed that seven gene arrangements were identified based on PCGs in the infraorder Astacidea, with type I being the most common.

CONCLUSIONS

The relationship between the American Cambaridae is closer to Astacidae than the Asian Cambaridae. The present study provides a theoretical basis for further discussions of developmental relationships in the infraorder Astacidea.