• Fisheries and Aquatic Sciences
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• 제20권11호
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• pp.29.1-29.7
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• 2017

The objective of this study was to determine a simple and reliable ploidy identification protocol for the rainbow trout (RT), Oncorhynchus mykiss, in the field condition. To evaluate the ploidy level and compare different detection protocols, triploid RT and gynogenesis were induced by UV irradiation and/or heat shock. The hatching rate at day 30 was 85.2% and the survival rate at day 90 was 69.4% (fingerling). The sex ratio of female RT was 93.75% in the gynogenesis group, illustrating that the UV irradiation inactivated the sperm DNA. The hatching rate and survival rate were 82.0 and 74.7%, respectively, in the triploid-induced group. The triploid induction rate by heat shock procedure was 73.9%. Cytogenetic protocols for ploidy identification such as chromosome counting, erythrocyte nuclear size comparison, and analysis of nucleolar organizing regions (NORs) by silver staining were compared. Silver nitrate staining showed the greatest success rate (22/23 and 32/32 for the triploid-induced group and gynogenesis group, respectively), followed by erythrocyte nuclear size comparison (16/23 and 19/32 for the triploid-induced group and gynogenesis group, respectively) and, lastly, chromosome preparation (2/23 and 6/32 for the triploid-induced group and gynogenesis group, respectively) with the lowest success rate. Based on our findings, silver staining for RT ploidy identification is speculated to be highly applicable in a wide range of research conditions, due to its cost-effectiveness and simplicity compared to other numerous ploidy detection protocols.

• 한국어류학회지
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• 제24권1호
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• pp.1-10
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• 2012

미꾸라지, 미꾸리 및 상반교배를 통해 유도된 종간 잡종의 세포유전학적 분석을 수행하였다. 미꾸라지와 미꾸리의 염색체 수는 각각 2n=48 (12M+4SM+32A), 2n=50 (10M+4SM+36A)이었고, 잡종군들의 염색체수는 각각 2n=49 (11M+4SM+34A)였다. 모든 그룹의 염색체는 동일한 arm number (NF=64)를 갖고 있었으며, 염색체 다형현상, 암수 간 이형의 염색체는 관찰되지 않았다. 적혈구의 크기, DNA 함량을 분석한 결과 잡종군들은 미꾸라지와 미꾸리의 중간 값을 나타냈다. 염색체의 NORs (nucleolar organizing regions)은 모두 동일한 중부염색체 단완부에서 Ag-positive signal이 나타났다. 이상의 결과는 미꾸라지의 1번 중부 염색체와 미꾸리의 차단부 염색체가 Robertsonian 형의 염색체 전좌 과정을 거쳤을 것을 시사한다.

• Molecules and Cells
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• 제19권3호
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• pp.436-444
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• 2005

We describe the morphology and molecular organization of heterochromatin domains in the interphase nuclei, and mitotic and meiotic chromosomes, of Brassica rapa, using DAPI staining and fluorescence in situ hybridization (FISH) of rDNA and pericentromere tandem repeats. We have developed a simple method to distinguish the centromeric regions of mitotic metaphase chromosomes by prolonged irradiation with UV light at the DAPI excitation wavelength. Application of this bleached DAPI band (BDB) karyotyping method to the 45S and 5S rDNAs and 176 bp centromere satellite repeats distinguished the 10 B. rapa chromosomes. We further characterized the centromeric repeat sequences in BAC end sequences. These fell into two classes, CentBr1 and CentBr2, occupying the centromeres of eight and two chromosomes, respectively. The centromere satellites encompassed about 30% of the total chromosomes, particularly in the core centromere blocks of all the chromosomes. Interestingly, centromere length was inversely correlated with chromosome length. The morphology and molecular organization of heterochromatin domains in interphase nuclei, and in mitotic and meiotic chromosomes, were further characterized by DAPI staining and FISH of rDNA and CentBr. The DAPI fluorescence of interphase nuclei revealed ten to twenty conspicuous chromocenters, each composed of the heterochromatin of up to four chromosomes and/or nucleolar organizing regions.