Background: Dissolved oxygen in water is an important limiting factor for fish. In this study, the suffocation point and transcriptomes analysis of&nbsp;Acrossocheilus fasciatus with different age and gender are helpful to analyze the effects of gender and age on extreme hypoxia tolerance. 
 
Methods: First of all, we compared the difference in tolerance to extreme hypoxia among 15 fish from male adult fish, female adult fish and juvenile fish of Acrossocheilus fasciatus in each group by asphyxiation point experiment. Then, we analyzed the molecular mechanism of extreme hypoxia tolerance difference between male and female adult fish and juvenile fish by transcriptomics.&nbsp; 
 
Result: Female adult fish of Acrossocheilus fasciatus showed the strongest tolerance to extreme hypoxia in the asphyxiation point experiment. In transcriptomes experiments in all samples, we found that the expression of ncoa4 and facl4 was significantly down regulated and the expression of jnk, gpx4 and jip-1 was significantly increased in females adult fish.

​Molecular Mechanism of Extreme Hypoxia Tolerance Difference between Male and Female Adult Fish and Juvenile Fish of Acrossocheilus fasciatus by Transcriptomics

<div>Background: Accurate species delimitation is essential for phylogenetic, phylogeographic, ecological, conservation and biogeographic investigations. Acrossocheilus species classification has long been contentious, owing to their uncertain evolutionary relationships, high levels of morphological homoplasy and a lack of knowledge of the taxonomic validity of conventionally utilized morphological characters. 
 
Methods: A final data set consisting of 102 mitochondrial cytochrome oxidase I (COI) gene sequences was analysed for K2P intraspecific and interspecific divergence in the current study, using reconstruction methods (maximum likelihood) and various models (ABGD, PTP, GMYC) to divide the sequences according to the pattern of genetic variation. We used landmark-based geometric morphometrics to identify specimens. 
 
Result: Two taxa were identified according to the phylogenetic tree (maximum likelihood method) and three different models (ABGD, PTP, GMYC). The molecular taxonomy of Acrossocheilus agreed with the morphological identification of specimens from the same collection locality. Therefore, the COI gene and geometric morphometrics were effective in species identification of A. fasciatus.</div>

Identification of Acrossocheilus fasciatus (Teleostei: Cyprinidae) from Three Different Phylogeographic Sources using Morphology and COI DNA Barcoding

​Molecular Mechanism of Extreme Hypoxia Tolerance Difference between Male and Female Adult Fish and Juvenile Fish of Acrossocheilus fasciatus by Transcriptomics

Identification of Acrossocheilus fasciatus (Teleostei: Cyprinidae) from Three Different Phylogeographic Sources using Morphology and COI DNA Barcoding

Molecular Mechanism of Extreme Hypoxia Tolerance Difference between Male and Female Adult Fish and Juvenile Fish of Acrossocheilus fasciatus by Transcriptomics