Life-history traits of a fluorescent Anopheles arabiensis genetic sexing strain introgressed into South African genomic background

• Published in: Malaria Journal
• Main Authors: Nonhlanhla L. Ntoyi, Thabo Mashatola, Jérémy Bouyer, Carina Kraupa, Hamidou Maiga, Wadaka Mamai, Nanwintoum S. Bimbile-Somda, Thomas Wallner, Danilo O. Carvalho, Givemore Munhenga, Hanano Yamada
• Format: Article in Journal/Newspaper
• Language: English
• Published: BMC 2022
• Subjects: Malaria; Vector control; COPAS; Arctic medicine. Tropical medicine; RC955-962; Infectious and parasitic diseases; RC109-216; Arctic
• Online Access: https://doi.org/10.1186/s12936-022-04276-6; https://doaj.org/article/f0adb75ef39b49e78ab76acbeb0375a7

Abstract Background South Africa has set a mandate to eliminate local malaria transmission by 2023. In pursuit of this objective a Sterile Insect Technique programme targeting the main vector Anopheles arabiensis is currently under development. Significant progress has been made towards operationalizing the technology. However, one of the main limitations being faced is the absence of an efficient genetic sexing system. This study is an assessment of an An. arabiensis (AY-2) strain carrying the full Y chromosome from Anopheles gambiae, including a transgenic red fluorescent marker, being introgressed into a South African genetic background as a potential tool for a reliable sexing system. Methods Adult, virgin males from the An. arabiensis AY-2 strain were outcrossed to virgin females from the South African, Kwazulu-Natal An. arabiensis (KWAG strain) over three generations. Anopheles arabiensis AY-2 fluorescent males were sorted as first instar larvae (L1) using the Complex Object Parametric Analyzer and Sorter (COPAS) and later screened as pupae to verify the sex. Life history traits of the novel hybrid KWAG-AY2 strain were compared to the original fluorescent AY-2 strain, the South African wild-type KWAG strain and a standard laboratory An. arabiensis (Dongola reference strain). Results The genetic stability of the sex-linked fluorescent marker and the integrity and high level of sexing efficiency of the system were confirmed. No recombination events in respect to the fluorescent marker were detected over three rounds of introgression crosses. KWAG-AY2 had higher hatch rates and survival of L1 to pupae and L1 to adult than the founding strains. AY-2 showed faster development time of immature stages and larger adult body size, but lower larval survival rates. Adult KWAG males had significantly higher survival rates. There was no significant difference between the strains in fecundity and proportion of males. KWAG-AY2 males performed better than reference strains in flight ability tests. Conclusion The life ...