Tick ​​decoded – sequencing its genome will help in the fight against Lyme – Focus

The ongoing 10 years project implemented an international research team (93 authors from 46 units) under the leadership of scientists from Purdue University (USA).

Ixodes scapularis is the first species of tick, whose genome was sequenced – the study proved to be more difficult than in the case of malaria carrying mosquitoes and ticks themselves considered less dangerous. “This genome ushers in a new era in the study of ticks,” – said the lead author, Professor. Catherine Hill from Purdue University.

Ticks transmit more diseases and parasites than any other arthropod, among them the devastating organism Lyme disease, which according to estimates by the Centers for Disease Control falls annually more than 300 000 Americans (only every tenth case is properly diagnosed and reported). Because of these diseases (anaplasmosis, babesiosis virus, Powassan encephalitis) die every year thousands of people and animals. To suck the blood of the host, ticks pierce his skin and bring to a wound in their saliva, which can be infected.

The study covered both the genes and proteins that facilitate parasitism and disease transmission. This should help in the development of new drugs and vaccines. It seems that up to 20 percent. sequenced all the genes in the genome of ticks occurs only in these arachnids.

We also managed to learn more about the unique aspects of the biology of the tick. For example, the saliva contains substances bactericidal, analgesic, anticoagulant and immunosuppressive, which allow it to quietly suck blood from the host, even for weeks. These substances are thousands (while blood mosquito contains hundreds of them), which allows the use of a variety of hosts.

The researchers also identified genes allowing ticks to produce new carapace during foraging – so you can zoom in even a hundred times as well those that facilitate feeding on the blood contains large amounts of iron (excess iron is toxic).

Another unique feature of the ticks are enzymes, so that they can inactivate insecticides.

One of the biggest challenges for the scientists was the complexity of the genome tick – to be the largest genomes of arthropods, which so far sequenced. What is interesting about 70 percent. genome are the genes repeated frequently mutated. Perhaps the different copies of the same gene are slightly different action to facilitate arachnids survival.

By the way, was able to explain that ticks Ixodes scapularis occurring in the south and north of the United States do not differ genetically sufficiently to render them two distinct species. However, since more cases of Lyme disease occurs in the north, probably a genetic trait of local ticks is important for the transmission of the disease. (PAP)