Genetic studies on human population residing in High Level Natural Radiation Areas of Kerala coast

摘要

For the past few decades, the monazite bearing coastal belt of Kerala in South West India is under investigation, to study the biological and health effects of natural chronic low dose exposure of background radiation, on human population residing in that area. The level of background radiation varies from > 1 mGy per year to 45 mGy per year and the areas with a dose level of <1.5 mGy per year are considered as Normal Level Natural Radiation Areas (NLNRAs), whereas areas having the background dose > 1.5mGy per year are High Level Natural Radiation Areas (HLNRAs). The nonuniform distribution of radiation level in this coastal belt provides a unique opportunity to study in vivo dose response of biological parameters. A number of studies have been conducted in this area, including cytogenetic investigation on newborns and adults for chromosomal aberrations, monitoring the newborns for congenital malformations and genetic disorders. Health Audit Survey to find out prevalence of late onset diseases and DNA mutation rate of the families using hyper-variable markers such as mini- and microsatellites. In the present paper, the findings obtained from two recently published reports dealing with spontaneous frequency of micronuclei among newborns and telomere length of adult population from high and normal level radiation areas have been highlighted. The spontaneous frequency of micronuclei (MN) was estimated in 271 newborns, whereas telomere length was determined from 310 adults. Our data did not reveal any significant difference in HLNRA as compared to NLNRA in both the parameters studied. No dose response was observed. In conclusion, the elevated background radiation prevailing in Kerala coast has no significant effect on the induction of micronuclei in newborns and telomere length in adults, which is in agreement with other studies conducted so far. Using advanced molecular biological techniques, further studies are in progress, to understand the cellular and molecular response of human cells to low dose radiation exposure.