Converting female mosquitoes to non-biting males with implications for mosquito control

Male mosquitoes don’t chew and are unable to transmit pathogens to people. Feminine mosquitoes, however, are capable of chew.

Feminine Aedes aegypti mosquitoes require blood to provide eggs, making them the prime carriers of the pathogens that trigger Zika and dengue fever in people.

“The presence of a male-determining locus (M locus) establishes the male intercourse in Aedes aegypti and the M locus is just inherited by the male offspring, very similar to the human Y chromosome,” stated Zhijian Tu, a professor within the Division of Biochemistry within the Faculty of Agriculture and Life Sciences.

“By inserting Nix, a beforehand found male-determining gene within the M locus of Aedes aegypti, right into a chromosomal area that may be inherited by females, we confirmed that Nix alone was adequate to transform females to fertile males. This may increasingly have implications for growing future mosquito management strategies.”

These findings had been printed within the Proceedings of the Nationwide Academy of Sciences.

“We additionally found that a second gene, named myo-sex, was wanted for male flight. This work sheds gentle into the molecular foundation of the perform of the M locus, which comprises a minimum of 30 genes,” stated Azadeh Aryan, a analysis scientist in Tu’s lab and the primary creator on the paper.

Aryan and colleagues generated and characterised a number of transgenic mosquito traces that expressed an additional copy of the Nix gene underneath the management of its personal promoter. Maria Sharakhova, an assistant professor of entomology within the Faculty of Agriculture and Life Sciences, and Anastasia Naumencko, a former graduate analysis assistant, mapped the chromosomal insertion website of the additional copy of Nix.

The Virginia Tech workforce, in collaboration with Zach Adelman’s lab within the Division of Entomology at Texas A&M College and Chunhong Mao of the Biocomplexity Institute & Initiative on the College of Virginia, discovered that the Nix transgene alone, even with out the M locus, was adequate to transform females into males with male-specific sexually dimorphic options and male-like gene expression.

“Nix-mediated intercourse conversion was discovered to be extremely penetrant and steady over many generations within the laboratory, which means that these traits will probably be inherited for generations to return,” stated Michelle Anderson, a former member of the Adelman and Tu labs and at present a senior analysis scientist on the Pirbright Institute in the UK.

Though the Nix gene was capable of convert the females into males, the transformed males couldn’t fly as they didn’t inherit the myo-sex gene, which can be situated within the M locus.

Knocking out myo-sex in wild-type males confirmed that the shortage of myo-sex within the sex-converted males is the explanation why they may not fly. Though flight is required for mating, the sex-converted males had been nonetheless capable of father viable sex-converted progeny when introduced with cold-anesthetized wild-type females.

“Nix has nice potential for growing mosquito management methods to cut back vector populations by female-to-male intercourse conversion, or to help within the Sterile Insect Method, which requires releasing solely nonbiting males,” stated James Biedler, a analysis scientist within the Tu lab.

Genetic strategies that depend on mating to manage mosquitoes goal just one particular species. On this case, the Tu workforce is concentrating on Aedes aegypti, a species that invaded the Americas a number of hundred years in the past and poses a risk to people.

Nevertheless, extra analysis is required earlier than probably helpful transgenic traces might be generated for preliminary testing in laboratory cages. “One of many challenges is to provide transgenic traces that convert females into fertile, flying male mosquitoes by inserting each the Nix and myo-sex genes into their genome collectively,” stated Adelman.

Because the Tu workforce seems to be to the close to future, they want to discover the mechanism by which the Nix gene prompts the male developmental pathway. The workforce can be eager about studying about the way it evolves inside mosquito species of the identical genus.

“We have now discovered that the Nix gene is current in different Aedes mosquitoes. The query is: how did this gene and the sex-determining locus evolve in mosquitoes?” stated Tu, who can be an affiliated college member of the Fralin Life Sciences Institute.

Along with diving into the depths of the Nix gene in mosquitoes, researchers hope that these findings will inform future investigations into homomorphic intercourse chromosomes which are present in different bugs, vertebrates, and vegetation.