Puffing patterns in the salivary gland chromosomes of the melonfly,Dacus cucurbitae

✍ Scribed by H. N. B. Gopalan; C. M. S. Dass

• Book ID: 104630322
• Publisher: Springer Netherlands
• Year: 1972
• Tongue: English
• Weight: 609 KB
• Volume: 43
• Category: Article
• ISSN: 0016-6707
• DOI: 10.1007/bf00122499

✦ Synopsis

The puffing pattern changes in the salivary gland chromosomes of the third instar larvae of the melonfly, Dacus cucurbitae are described. Three classes of puffs were noticed over a period of development of 120 hrs. Class (1) are those which are more or less constantly found; class (2) are those which oscillate, i.e. appear and disappear at irregular time intervals; and class (3) are those that are linked to a specific developmental event. Also, 3 peaks of puffing activity have been noticed during the present study; one in the 120 hr old larva, the second in the 168 hr old larva and the third in the 240 hr old larvae. The significance of these 3 classes of puffs and the 3 peaks in puffing activity has been discussed. The puff RNA has a high rate of synthesis and incorporates 3H-cytidine within 30 secs after being offered. There is a high degree of variation in the incorporation of labelled precursors into the different nuclei of the same gland, such a variation is not noticed in the diploid and embryonic cells.