The Karyotype of Fischoedeyius cobboldi (Poirier, 1883) from Korean Cattle

한국산 코볼드쌍구흡충의 핵형 분석

As a series of systematic classification of paramphistomes, the worms in the rumen and reticulum of 310 Korean cattle slaughtered at Chonju abattoir were collected from February 1986 to June 1987 and were classified by morphology of the worms. Afterwards, the karyotype of Fischoederius cobboldi (Poirier, 1883), which is a very rare species in Korean cattle, was studied with germ cells of the worm by means of modified air-drying method. The chromosome numbers in the haploid and diploid cells of 315 F. cobboldi were n=9 and 2n=18, respectively. The meiotic divisions were observed frequently; 1,904 haploid and 49 diploid cells were recognized. Nine pairs of mitotic chromosomes were homologous in the metaphase stage and the chromosomes were composed of seven medium-sized metacentrics (m) or submetacentrics (sm) and two small-sized submetacentrics (sm). While, meiotic metaphases were composed of seven medium and two small·sized chromosomes. The 3rd, 4th, 2nd and 5th pairs of chromosomes was metacentric having centromere indices of 40.4%, 40.0%, 39.7% and 38.9%, respectively, and the remaining ones were submetacentric with centromere indices from 32,4% to 36.2%. As a series of C-banding method, C-band was shown in centromeric region from all of the haploid germ cells, except chromosome No. 1 which included heterochromatin at the tip region. Chromosomes No, 4, 6 and 9 showed remarkable C-band distinguished from others.

한국산 쌍구흡충의 계통분류를 하기 위한 연구치 일환으로 한우로부터 코볼드쌍구흡충(Fisthoederius robbozdi)을 채집한 다음 정소부위를 colchicine으로 단시간 처리하는 자연건조법을 응용하여 핵형을 분석하였다. 코볼드쌍구흡충 총 315개체의 생식세포에 대하여 염색체수를 조사한 바 n=9, 2n=18이었으며, 1,904개의 반수체성 중기염색체와 49개의 이배체성 중기염색체를 확인하였다. 이배체성 중기염색체는 7쌍의 중형염색체와 2쌍의 소형염색체로 구성되어 있었고, 반수체성 염색체는 중형 7개와 소형 2개로 구성되어 있었다. 동원체지수는 3번 염색체가 40.4%로서 9쌍중에서 동원체가 염색체의 가장 중앙부위에 위치하는 중부착사 염색체이었으며, 그 나머지의 것들은 32.4∼40.0%이었다. 분염법(C-banding)에 의한 생식세포의 반수체성 염색체는 핵형을 구성하는 이염색질이 거의 모든 염색체의 동원체 부위에 존재하였지만, 1번 염색체는 염색체 첨단에 이염색질이 농염되어 있었으며 .4, 6, 8번 염색체의 이염색질은 크고 진하게 관찰되었다.