Replication in drosophila chromosomes III. Disproportionate replication of hetero- and eu-chromatin in wing imaginal disk cells of D. nasuta larvae
✍ Scribed by S. C. Lakhotia
- Publisher
- Springer Netherlands
- Year
- 1981
- Tongue
- English
- Weight
- 398 KB
- Volume
- 54
- Category
- Article
- ISSN
- 0016-6707
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✦ Synopsis
Wing imaginal disks of 3rd instar larvae of Drosophila nasuta were labelled in vivo with 3H-thymidine for 46h by a feeding method. Observations on autoradiographs of these imaginal disk cells reveal that nearly all interphase nuclei became labelled with 3H-thymidine. However, on average, while 50% of nuclei show labelling of their heterochromatic chromocentre as well as euchromatic regions, only the euchromatic regions are labelled with the chromocentre remaining distinctly unlabelled in about 46% of the nuclei. It is suggested that many of the wing imaginal disk cells of 3rd instar larvae may be undergoing endo-reduplication cycles with under-replication of heterochromatin. nantly diploid cells (Gall et al., 1971;Fristrom, 1972). However, the observations presented here suggest that the undifferentiated imaginal disk cells of 3rd instar larvae of D. nasuta may not be typically diploid; instead, it seems that many of these cells are endoreduplicated with a disproportionate replication of hetero-and err-chromatic regions.