中国渤海鱼类寄生异尖属线虫幼虫的分子鉴定和遗传多样性分析(线虫纲,蛔总科)(英文)

MOLECULAR IDENTIFICATION AND GENETIC DIVERSITY OF ANISAKIS LARVAE (NEMATODE,ASCARIDOIDEA) FROM MARINE FISHES IN THE BOHAI SEA,CHINA

2008年5月至2009年5月间对渤海鱼类寄生线虫的幼虫进行了采集。通过形态学观察,从172条(5种)鱼类体内共鉴定出612条异尖属线虫的幼虫。每条幼虫分布提出基因组DNA,利用PCR技术扩增出ITS区,并用限制性内切酶(HinfⅠ,TaqⅠand HhaⅠ)进行酶切分析。随后选择有代表性的样品进行ITS-1,ITS-2,以及线粒体DNA SSU序列分析。对612个样品进行酶切分析后,发现两种不同的基因型,其中603个样品为派氏异尖线虫Anisakis pegreffii,9个样品为重组基因型。因此渤海鱼类中派氏异尖线虫为优势种,占所检测样品的98.5%。对重组基因型的ITS-1和IT S-2进行序列分析表明有两种不同的重组基因型,重组基因型Ⅰ(RecⅠ)与以前报道的杂交种相同,在ITS-1的280和296部位有C/T的杂合;而重组基因型Ⅱ代表一种新的重组基因型,它只在296部位有C/T的杂合。线粒体DNA SSU序列分析表明两种重组基因型的序列与派氏异尖线虫完全相同。该结果表明重组基因型有可能是一种祖先多态性的保留。

A total of 612 larval specimens of Anisakis from 172 fishes （representing 5 species） from the Bohai Sea, China from May 2008 to May 2009 was identified based on morphological characters. From the genomic DNA of all individual specimens, a region of nuclear ribosomal DNA was amplified by polymerase chain reaction （PCR） , followed by restriction endonuclease digestion with endonucleases （Hinf I ,Tatl I and Hha I ）. Subsequently, FFS-1 and ITS-2, and mtDNA SSU gene of the selected samples were sequenced. The RFLP patterns of the 612 samples indicated two different genotypes representing Anisakis pegreffi （ n = 603 ） and recombinant genotype （ n = 9）. Thus, Anisakis pegrejfii was the dominant species, accounting for 98.5 % of the total number of specirnens examined herein. The sequence analysis of ITS- 1 and ITS- 2 in the recombinant genotype revealed two different genotypes, the recombinant subtype I （Rec I ） representing ＂hybrid＂ with heterozygotes C/T at positions 280 and 296 of the aligned sequences reported previously, whereas recombinant subtype II （Rec Ⅱ） representing an un-described recombinant with heterozygote C/T at position 296 of the aligned sequences. MtDNA SSU sequencing indicated the sequences of Rec I and Rec Ⅱ have same parental origin from Anisakis pegreffi. The result supported that the recombinant subtypes might be the retention of ancestral polymorphism.