https://doi.org/10.51514/JSTR.8.1.2026.33-38
Sandeep and Dharmendra Pratap Singh
Chironomidae are known to be one of the dominant families of Diptera present in near-water systems. Chironomids have salivary gland polytene chromosomes. These are advantageous to a cytogeneticist and can be utilized to identify species, map chromosomes, study their evolutionary relationships, and use them as a biomonitoring tool for environmental studies. The present study was done on Dicrotendipes sp. sampled from various locations in the Chambal River, India. Fourth-instar larvae were collected during the monsoon, and chromosomes were prepared using the aceto-orcein squash method. Cytogenetic studies showed that this species has a diploid chromosome number of 2n = 8 with chromosome arms AB, CD, EF, and G. Chromosomes AB and CD were metacentric, chromosome EF was sub-metacentric and chromosome G, which was telocentric, was the shortest chromosome in the set. Different cytological landmarks, like Nucleolar Organiser Regions (NOR), Balbiani Rings (BR), constriction, and heterochromatic bands, were seen in different chromosome arms. These landmarks are mainly used for species and cytotaxonomic identification. The current study provides preliminary insights into the cytogenetic structures for Dicrotendipes sp. in the studied River system and provides insights into the organization of chromosomes and the different forms of Indian chironomids.
Keywords: Dicrotendipes, Chironomidae, Chambal River, Cytogenetics, Balbiani Ring, polytene chromosomes, NOR etc.