Nuclear and mitochondrial DNA analysis reveals that hybridization between Fasciola hepatica and Fasciola gigantica occurred in China.
The well-known pathogens of fasciolosis, Fasciola hepatica (Fh) and Fasciola Gigantica (Fg), possess abundant mature sperms in their seminal vesicles, and thus, they reproduce bisexually. On the other hand, aspermic Fasciola flukes reported from Asian countries, which have no sperm in their seminal vesicles, probably reproduce parthenogenetically. The aim of this study was to reveal the origin of aspermic Fasciola flukes. The nuclear single copy markers, phosphoenolpyruvate carboxykinase and DNA polymerase delta, were employed for analysis of Fasciola species from China. The hybrid origin of aspermic Fasciola flukes was strongly suggested by the presence of the Fh/Fg type, which includes DNA fragments of both F. hepatica and F. gigantica. China can be regarded as the cradle of the interspecific hybridization because F. hepatica and F. gigantica were detected in the northern and southern parts of China, respectively, and hybrids flukes were distributed between the habitats of the two species. The Chinese origin was supported by the fact that a larger number of mitochondrial NADH dehydrogenase subunit 1 (nad1) haplotypes was detected in Chinese aspermic Fasciola populations than in aspermic populations from the neighbouring countries. Hereafter, 'aspermic' Fasciola flukes should be termed as 'hybrid' Fasciola flukes.
Laboratory of Veterinary Parasitology, Faculty of Agriculture,Iwate University,Ueda 3-18-8,Morioka 020-8550,Japan.
Madoka
M
Ichikawa-Seki
Academy of Animal and Veterinary Medicine,Qinghai University,No. 251 Ningda Lu,Xining 810016,China.
Mao
M
Peng
Laboratory of Veterinary Parasitology, Faculty of Agriculture,Iwate University,Ueda 3-18-8,Morioka 020-8550,Japan.
Kei
K
Hayashi
Laboratory of Veterinary Parasitology, Faculty of Agriculture,Iwate University,Ueda 3-18-8,Morioka 020-8550,Japan.
Takuya
T
Shoriki
Laboratory of Veterinary Parasitology, Faculty of Agriculture,Iwate University,Ueda 3-18-8,Morioka 020-8550,Japan.
Uday Kumar
UK
Mohanta
Laboratory of Comparative Animal Science,Department of Animal Pharmaceutical Science,Faculty of Pharmacy,Chiba Institute of Science,Shiomi-Cho-3,Choshi,288-0025,Japan.
Toshiyuki
T
Shibahara
Laboratory of Veterinary Parasitology, Faculty of Agriculture,Iwate University,Ueda 3-18-8,Morioka 020-8550,Japan.
Tadashi
T
Itagaki
D000818:Animals; D002681:China; D018509:DNA, Helminth / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000235:genetics; D005209:Fasciola / Q000235:genetics*; D005786:Gene Expression Regulation / Q000502:physiology; D006239:Haplotypes; D015801:Helminth Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D012669:Seminal Vesicles; D013045:Species Specificity; D013091:Spermatogenesis / Q000235:genetics / Q000502:physiology; D013094:Spermatozoa
D018509:DNA, Helminth; D004272:DNA, Mitochondrial; D015801:Helminth Proteins

               Fasciola
            ; 
               nad1
            ; 
               pepck
            ; 
               pold
            ; China; geographical origin; hybridization