Enrichment of phenotype among biological forms of Anopheles stephensi Liston through establishment of isofemale lines

• Published in: bioRxiv
• Main Authors: Ghosh, Chaitali, Kumar, Naveen, Raja Babu Singh Kushwah, Soumya, M, Joshi, Soumya Gopal, Chethan Kumar R, Alalamath, Tejashwini, Srinivasan, Subhashini, Subramani, Suresh, Kumar, Sampath, Swain, Sunita
• Format: Paper
• Language: English
• Published: Cold Spring Harbor Cold Spring Harbor Laboratory Press 28.09.2022
• Subjects: Anopheles stephensi; Culicidae; Eggs; Genomes; Genotype & phenotype; Genotypes; Inbreeding; Inbreeding depression; Insecticides; Malaria; Morphometry; Mosquitoes; Phenotypes; Vectors
• DOI: 10.1101/2022.09.28.509862

The success of vector management programs relies on knowledge of the biology and genetic make-up of mosquitoes so that they can be interlaced with modern tools for developing suitable intervention strategies. There are many reports available for rearing varied species of mosquito vectors. However, there are limited studies addressing the development of isofemale lines among mosquitoes to homogenize the population to obtain both high-quality genome assemblies and enrichment of phenotype. Anopheles stephensi, an urban malaria vector, is one of the major invasive vectors of malaria distributed throughout the Indian subcontinent, Middle East, and has recently been expanding its range in Africa. With the existence of three biological forms, distinctly identifiable based on the number of ridges on eggs with varying vectorial competence, An. stephensi is a perfect species for developing a method for the successful establishment of isofemale lines, which can be tested for retention of the expected vectorial competence for the various forms. We describe the key steps in the establishment and validation of isofemale lines, which include monitoring the transgenerational fitness traits, morphometrics of eggs, and adult wing size during every generation. After the initial inbreeding depression, as proof of the tedious selection process, no significant morphometric differences were observed in the wings and egg size between the parental and their respective isofemale lines. We observed a significant change in the vectorial competence between the respective isofemale and parental lines enriching expected differential susceptibility towards malaria parasites by the type and intermediate forms. Interestingly, IndCh and IndInt strains showed variations in resistance to different insecticides belonging to all the four major classes. These variant lines have been characterized for their levels of homozygosity both at the phenotype and genotype levels and can be used as a standard reference or as a biological resource for other studies related to urban malaria research. Competing Interest Statement The authors have declared no competing interest.