Abstract
The diploid chromosome number of two species of sidenecked turtles (Podocnemis unifilis and P. expansa) was found to be 28. Under normal culture conditions, half of the chromosomes of P. unifilis consistently show one or two clear secondary constrictions. In P. expansa, the incidence of cells with chromosomes bearing secondary constrictions and the number of such chromosomes per cell are less. Cells of two P. unifilis cell lines maintained a normal diploid karyotype for two years following their initiation. Then one cell line shifted to a hypodiploid mode of 27 and half of the population of the second line became pseudodiploid, the other half remaining diploid. A single six-month-old cell line from P. expansa has maintained a normal diploid mode through 10 passages.
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Supported in part by grant-CA 08737 from the National Cancer Institute.
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Huang, C.C., Clark, H.F. Chromosome studies of the cultured cells of two species of side-necked turtles (Podocnemis unifilis and P. expansa). Chromosoma 26, 245–253 (1969). https://doi.org/10.1007/BF00326519
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DOI: https://doi.org/10.1007/BF00326519