Chromosomal rearrangements in Chironomus sp. as genosensors for monitoring environmental pollution

Abstract

The main objective of our research was to use the polytene system existent in the larvae stage of the common Diptera species of Chironomus as a tool for identifying genomic sensors in evaluating the environmental pollution degree. We analysed polytene chromosomes of larvae of two populations from  two  polluted  regions:  Bucharest  (collected  from  some  pools  of  Botanical  Garden)  and  from Mureş Valley, Western area of Romania.  627 cells from 55 larvae of the Bucharest population and 352 cells from  30 larvae  of the Mures Valley were  analyzed for the chromosomal  aberrations  and were  processed  using  both  acetocarmine  staining  method  and  DAPI  staining  for  polytene chromosome squashes. In both populations a large number of somatic chromosomal rearrangements of  their  polytene  chromosomes  were  encountered.  The  changes  in  the  puffing  pattern  were  also considered. Since a large array of different chromosomal rearrangement was evidenced in these two analysed  populations  we  concluded  that  Chironomus  chromosomal  polytene  complement  might  be considered as an ideal tool in searching for the genomic sensors used in evaluation of environmental pollution  degree.  All  the  rearrangements  identified  in  Chironomus  sp  polytene  chromosomal complement  can  be  considered  as  biomarkers which  provide  early warning  signals  of the  adverse long term genotoxic effects of the pollution in different other organisms.