DNA content of hepatocyte and erythrocyte nuclei of the spined loach (Cobitis taenia L.) and its polyploid forms
We analyzed the DNA content of hepatocyte and erythrocyte nuclei of the spined loach Cobitis taenia (diploid) and its allopolyploid forms. Twenty triploid females and one tetraploid were used. At least 20,000 hepatocyte and erythrocyte nuclei were acquired and analyzed by flow cytometry. C. taenia erythrocyte nuclei contain 3.15 ± 0.21 pg of DNA and the hepatocyte nuclei 4.45 ± 0.46 pg of DNA. Triploid Cobitis have 5.08 ± 0.41 pg of DNA in erythrocyte nuclei and 6.11 ± 0.40 pg of DNA in hepatocyte nuclei, whereas the tetraploid erythrocyte and hepatocyte nuclei contained 6.60 and 7.40 pg of DNA, respectively. In general, the DNA contents correlate positively with the ploidy level of the fish investigated. The DNA content variation in the hepatocyte and erythrocyte nuclei may be due to differences in extent of chromatin condensation, which is more pronounced in the erythrocyte than hepatocyte nuclei, or to the several orders of ploidy that occur in the parenchymal liver cells.
KeywordsCobitis DNA Polyploidy Spined loach
We thank Professor Elżbieta Pyza chief of the Department for providing facility used during this study and hospitality for one of us (W·K.), Dr. Gregory Tylko who introduced me (W·K.) to the techniques of Flow Cytometry. We would like to thank N.J. Severs for critical comments on the manuscript.
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