Researchers discover potential method to control mosquito populations
Control methods for limiting the spread of Aedes aegypti mosquitoes may be on the horizon, thanks to Virginia Tech scientists.
GREENVILLE, N.C. (WITN) - The summer months in the Southeast are known for the heat and humidity, and it’s common knowledge the rise in summer temperatures leads to a rise of local mosquito populations. Researchers at Virginia Tech have been studying the genetic make-up of Aedes aegypti, the mosquito species known for carrying dangerous pathogens, like the chikungunya virus, zika virus, dengue fever and yellow fever. Recent discoveries have shown possible control strategies by altering the genetic code in the female mosquitoes.
Dr. Zhijian Tu, a professor in Virginia Tech’s Biochemistry department, in conjunction with Zach Adelman’s lab in the Department of Entomology at Texas A&M University and Chunhong Mao of the Biocomplexity Institute & Initiative at the University of Virginia, isolated the chromosomal region that determines sex in the Aedes aegypti mosquito and discovered a way to convert female mosquitoes into fertile male mosquitoes.
“The presence of a male-determining locus (M locus) establishes the male sex in Aedes aegypti and the M locus is only inherited by the male offspring, much like the human Y chromosome. By inserting Nix, a previously discovered male-determining gene in the M locus of Aedes aegypti, into a chromosomal region that can be inherited by females, we showed that Nix alone was sufficient to convert females to fertile males. This may have implications for developing future mosquito control techniques.”
Female mosquitoes bite humans to gain blood needed to produce fertile eggs. They are also the carriers of debilitating and sometimes deadly diseases. Male mosquitoes do not bite humans, instead sucking nectar from flowers.
One issue that arose during the research was the female-to-male Nix conversion lead to flightless male mosquitoes. Flight is necessary for mosquitoes to mate in the wild. They found that the myo-sex gene, also located in the M locus, determined whether or not the male mosquito could fly. The Nix gender conversion coupled with the addition of the myo-sex gene would lead to female-to-male converts that were both fertile and able to fly.
Michelle Anderson, a former member of the Adelman and Tu lead research labs, said “Nix-mediated sex conversion was found to be highly penetrant and stable over many generations in the laboratory, meaning that these characteristics will be inherited for generations to come.”
By introducing large numbers of the Nix converted male mosquitoes into the wild, scientists are hopeful the number of the disease-carrying and biting Aedes aegypti female mosquitoes will decline rapidly, reducing human exposure to dengue fever, yellow fever and other dangerous and deadly diseases.
Jutras, Kristin R, and Kendall Daniels. “Researchers Convert Female Mosquitoes to Nonbiting Males with Implications for Mosquito Control.” Virginia Tech Daily | Virginia Tech, 14 July 2020, vtnews.vt.edu/articles/2020/07/fralinlifesci-pnas-transgenics-mosquito-control.html.
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