Karyotype of Fasciola sp. obtained from Korean cattle

ABSTRACT

As a series of systematic classification for Korean common liver fluke, Fasciola sp., karyotype was investigated by means of the modified air-drying technique and of the regular Giemsa staining, Also, C-staining method was applied for detailed karyological analysis from the germ cells of the fluke. The following is a brief summary of the leading facts gained through the experiment. Korean Fasciola sp. was classified into three types based on their chromosomal complements; individuals with 20 or 30 chromosomes and with a 20/30 mosaic constitution. Worms having 30 chromosomes represent a triploid form with 3 sets of 10 basic chromosomes, while those with 20 chromosomes were diploid and mosaic individuals were 2n/3n mixoploid. The frequency of the individual type calculated is as follows; 67.45% of 212 flukes examined was of diploid, 10.85%, triploid, and the rest, 21.7%, mixoploid, respectively. In many cases, two or three types were found in the peculiar bovine host while single type inhabitant was about 20% out of 52 cases. The twenty chromosomes consisted of 1 parir of large metacentrics, 4 pairs of medium-sized subtelocentrics, and 5 pairs of small submetacentrics, while constitution of the thirty chromosomes was nearly interpreted as a triploid form with 3 sets of 10 basic chromosomes. The high centromeric indexes of both types are the first pairs among all the examined, and 37.93% was of diploid and 47.93%, triploid, respectively. In mixoploid individuals, constitution of the chromosomes of diploid or triploid cells was the same as that of diploid or triploid individuals. All the chromosomes of the germ cells in both types showed C-band around the centromeic region and especially the chromosomes no's 3, 7, and 8 showed a remarkable C-band distinguished from other chromosomes. The variance for the sizes of the worms and the eggs were not parallel with three different genotypes in Korean common liver fluke.