Genetic Structure ofAmphioctopus ovulum(Mollusca: Cephalopoda: Octopodidae) as Revealed by Mitochondrial and Nuclear DNA

Amphioctopus ovulumis an important species found along the China coast distributed from the East China Sea to the South China Sea. This is the first study about the population structure and diversity carried out for this species in the China Sea. Two mitochondrial DNA genes Cytochrome oxidase subunit 1 and Cytochrome b (CO1 & Cytb) and one nuclear DNA gene (Heat shock protein 70 (HSP-70) were used to assess the genetic structure among four populations spanning the eastern to southern regions of the Chinese coast. Fragments of 568, 831, and 836 bp in length, representing three genes (CO1, Cytb, and HSP-70) were amplified from 105,106 and 106 individuals, respectively. Overall, CO1 ("Hd" 0.579; "n" 0.00152), Cytb ("Hd" 0.610; "n" 0.00130) and HSP-70 ("Hd" 0.925; "n" 0.00652) showed high haplotype diversity and low nucleotide diversity. All three genes revealed lower molecular variance among populations and higher variance within populations. Relatively lower F(ST)values were obtained for CO1 ( F-ST=0.00357 to 0.1641), Cytb (F-ST=0.00522 to 0.01959), HSP-70 (F-ST=0.00498 to 0.08504) which indicated low genetic variation among populations. The phylogenetic analysis does not separate four populations. The network analysis revealed the occurrence of the main haplotype (H1 (mtDNA)) and (H2 HSP-70) shared by all populations and many secondary haplotypes originated from the principal for all the three markers. These results will enhance our understanding ofA.ovulumto allow better exploitation, protection, and management of this species.