Journal Article

Variability in Gene Expression and Tumor Formation within Genetically Homogeneously Animal Populations in Bioassays


in Toxicological Sciences

Volume 29, issue 2, pages 176-184
Published in print February 1996 | ISSN: 1096-6080
Published online February 1996 | e-ISSN: 1096-0929 | DOI:
Variability in Gene Expression and Tumor Formation within Genetically Homogeneously Animal Populations in Bioassays

More Like This

Show all results sharing these subjects:

  • Medical Toxicology
  • Toxicology (Non-medical)


Show Summary Details


Considerable variation in susceptibility to tissue-specific tumor formation in response to chronic treatment with low or intermediate dose levels of putative carcinogens is observed within populations of genetically homogeneous test animals under controlled environmental conditions. Experimental evidence from National Toxicology Program studies is reviewed, as are studies of differing degrees of carcinogenic response and tumor promotion among iso- and congenic mice carrying the Avy (viable yellow) mutation. The data suggest that individual variations in carcinogenic response among genetically homogeneous animals may derive primarily from differences in regulation of gene transcription. Differences in posttranscriptional and posttranslational processing of gene products are probably also contributing factors. The viable yellow Avy/a mouse model system is uniquely suited for investigating the developmental and molecular bases of this phenotypic variability in genetically homogeneous populations since various degrees of carcinogenic response and promotion of tumor formation can be predicted, a priori, at least as early as 7 days of age by correlation with coat color patterns. Ectopic expression of the agouti protein results in enhanced susceptibility to tumor formation in tissues which are already sensitized to neoplastic transformation by their strain genome. The differences in tumorigenic response and coat color pattern among Avy/– mice appear to be associated with different DNA methylation states of the promoter of an intracisternal A particle inserted into exon 1A of the agouti gene.

Journal Article.  0 words. 

Subjects: Medical Toxicology ; Toxicology (Non-medical)

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.