Cytological study of exfoliated buccal mucosa cells of tribes in Orissa State (India) with high risk for oral cancer.

Buccal mucosa scrapings from 50 individuals belonging to tribes of Koraput district in Orissa State (India), were smeared and fixed. The cells were stained adopting Feulgen technique. All the tribes are active tobacco and alcohol users. The individuals were asked about their age, sex, food habit, tobacco and alcohol consumption habit, period of consumption and daily consumption quantity. Micronuclei were scored from the smeared cells as increase in micronucleus frequency in buccal mucosa cells of tobacco and alcohol users indicates a high risk group for oral cancer. At least 1000 cells per sample were screened. The frequency of micronucleated cells is found to be higher (7.37%) in case of male individuals than female individuals (5.90%). Individuals of both sexes of age group (50-65) years show higher frequency of micronucleus. Tobacco smokers with Pika habit show higher frequency of micronucleus (7.06%) than tobacco chewers with Dungia habit (6.33%). Such increase in micronucleus frequency in buccal mucosa cells indicates that the tribes are high risk of oral cancer.

Abdominal pigmentation and growth temperature in Indian Drosophila melanogaster : Evidence for genotype-environment interaction.

Phenotypic variability for abdominal pigmentation in females of an Indian natural population of Drosophila melanogaster was studied using isofemale lines and by rearing the larvae and pupae at 4 different temperatures ranging from 20–30°C. The dark pigmented area was found to increase in all the three segments when the growth temperature decreases. A significant positive correlation was detected for the occurrence of dark pigmentation in the 5th and 6th segments in each growth temperature but for other comparisons the correlation was not regular. Analysis of variance (ANOVA) was carried out both for individual segments over different growth temperatures and also for each temperature over the three abdominal segments and in all cases found to be statistically significant. The results are quite different from the earlier observation in French Drosophila melanogaster and suggest that genes controlling pigmentation are temperature dependent; temperature could affect post-transitional events involved in pigmentation. The present findings also clearly indicate that significant genotype-environment interaction exists, responsible for the production of desired phenotype at the opportune moment during the life span of a species.