Control of polytenic replication in dipteran larvae. I. Increased number of cycles in a mutant strain of Drosophila melanogaster
✍ Scribed by Toby C. Rodman
- Publisher
- John Wiley and Sons
- Year
- 1967
- Tongue
- English
- Weight
- 640 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0021-9541
No coin nor oath required. For personal study only.
✦ Synopsis
Previous studies have demonstrated that a consistent maximum number of polytenic replication cycles occurs in the salivary gland nuclei of a wild-type strain of D. melanogaster. Since that number is achieved within the larval period, the DNA synthesis of the prepupal period is believed to be that of propagation of the final cycle. Photometric determinations have been made, in this study, of the salivary gland nuclei of larvae and prepupae of the tu-h strain in which the larval period has been extended as a consequence of delay or failure of pupation. The DNA values indictae that a higher maximum number of polytenic replications is achieved in such nuclei. It is inferred, thereby, that initiation of polytenic replication is a function of the larval state and, since it is terminated by the intervention of metamorphosis, a hormonal dependence is suggested.