ISSN:
1432-0886
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Summary The chromosomal content of nuclei of four tissues in males and females ofSteatococcus tuberculatus, a haploid-diploid species, was determined at each instar by means of cytophotometric measurement of the Feulgen nucleal reaction. Volumes of nuclei were calculated, and, wherever possible, chromosome counts were made. The results are summarized on pages 248–249. 1. It has been shown that hypodermal cells of the male have the haploid number of chromosomes, and that, as determined by DNA measurements, these chromosomes have the same valence as chromosomes in the female hypodermis. Neither a change in valence, nor in the number of chromosomes is essential to the viability of this tissue. 2. In the fat body, wax glands and Malpighian tubules the original 1∶2 ratio in chromosome content between male and female nuclei is replaced by ratios of 1∶1, 2∶1, and 1∶4 respectively. A sex-differential polyploidization, sensu latu, varying from tissue to tissue is thus demonstrated. 3. A definite correlation between secretory activity of the wax glands and the DNA content of the nuclei of wax gland cells has been demonstrated, but a causal relationship between the two has not been proven. 4. Nuclear volume has been shown to have no direct relation to DNA content even in polysomatic tissue. Changes in nuclear volume, correlated with age and feeding habits, and independent of DNA content, have been demonstrated in certain tissues of the male.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01259502
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