Researchers at Virginia Tech's College of Agriculture and Life Sciences have discovered unique interactions in five species of mosquito cells that provide a roadmap for eliminating the possibility of malaria and other diseases in the future. The findings were recently published in the journal Nature Communications. People use pesticides as much as possible to kill mosquitoes. However, this method of control does not distinguish between good and bad insects, but develops resistance to mosquitoes and live insects through natural selection and mutation. After years of relative success in controlling mosquito populations this way, mosquitoes are being re-evaluated for their significantly reduced effectiveness and environmental friendliness.

"We have to constantly invent new pesticides," said Igor Sharakhov, one of the project's researchers, a professor of entomology and affiliated with the Fralin Institute of Life Sciences. "With promising genomic approaches, we can create so-called gene drives and build structures that cannot suppress mosquito populations or transmit disease."

But for practical applications, scientists need to understand how the genome (the complete set of genes in a cell) is organized. To better understand this, Varvara Lukyanchikova, senior researcher of the international team and visiting scientist in the Department of Entomology, and other members of the project studied five species of mosquitoes that have evolved over 100 million years. - The evolution time of rats and humans is the same. The researchers wanted to examine the genome structure of the malaria mosquito using a method not previously used in these insects and identify what unique characteristics it has at the cellular level.

What we also discovered is that the mosquito genome is organized like any other genome, but it has active and inactive sections. Now we know which parts of the genome express and function genes," said Lukyanchikova, who works in Sharahov's lab and is affiliated with the Fralin Institute for Life Sciences. It can help, and it's a way to use the knowledge we've learned. in this study."

This project was supported by a three-year grant from the National Science Foundation. The research team developed a technique for mosquito embryos using Hi-C, developed about 10 years ago. This technique examines the three-dimensional structure of the genome and helps researchers determine which regions of the genome may interact with each other.

The idea is very simple, but the execution is a bit more complicated. The researchers took nuclei and used paraformaldehyde to preserve the proteins and DNA in space, binding them tightly together. The researchers then used the enzyme, ligase, to cut the DNA restrictively and link the DNA molecules in the nuclear space. An international research team has developed a technique for mosquito embryos using Hi-C, developed about 10 years ago. This technique studies the three-dimensional structure of the genome and helps researchers determine which regions of the genome may interact with each other.

Using this technique, the researchers isolated nuclei from the cells of five mosquito species: Cellia (An. coluzzii, An. merus, An. stephensi), Anopheles (An. atroparvus), and Nyssorhynchus (An. albimanus). After sequencing the library and collecting biological replicates, the researchers obtained between 60 million and 194 million unique alignments for each mosquito species.

Millions of cores should generate probabilities. For example, you have contact A and contact B. These contacts do not interact on each core. It only interacts with some cores. The method used allows us to estimate the number of interactions between these two contacts in the cell. Based on this probability, we can create a heatmap that shows how often these two trajectories touch. It is a powerful molecular technique that helps identify genome-wide interactions. The researchers then created a heat map and compared it to the five mosquito species studied. Although some similarities to mammals have been found, of particular interest are the polycomb clusters, the long-distance loops, two widely separated regions of the genome that form polycomb proteins not seen in other species. In this case, the loops were separated by a few megabases and were still strongly connected after finding each other in the central space.