Ural scientists edited DNA sections responsible for susceptibility to leukemia in cows

A team of geneticists, embryologists, biologists and veterinarians has been working for 3 years to develop a unique technology for editing the genome of cattle in order to obtain an animal with the desired characteristics. 

 “The idea of ​​the project is to combine advanced developments in embryology, molecular biology, genetic engineering, veterinary reproduction to create animals with improved traits not in 7-10 generations, but in a short time - by directly introducing small changes in the genome of those common in the Urals Holsteinized black-and-white cows. Now the improvement of some characteristics of cows takes place traditionally, through selection work, and this takes decades, ”explained Anna Sergeevna Krivonogova, project leader, leading researcher at the Laboratory of Biological Technologies of the Ural Research Institute of the Federal State Budgetary Scientific Institution UrFARC Ural Branch of the Russian Academy of Sciences, Doctor of Biological Sciences.

The main targets for scientists were DNA regions responsible for susceptibility to leukemia, polled (hornless) and the production of hypoallergenic milk. Leukemia is one of the most common infectious diseases of cattle in many countries of the world. It is forbidden to use milk from sick cows, and this directly affects the efficiency of any livestock enterprise. Polledness is an important point in commodity production: horned animals often injure each other and personnel. To avoid this, calves have their antlers removed in infancy. And the absence of allergenic protein in milk allows not only to use it for people with allergies, but also to make infant formula and dietary products from it.

Genome editing is a jewelry and very complex process. First of all, scientists had to determine the section of DNA where the desired gene is located, to find a way to deliver an editing system into the cell in order to block the section of the genome that is not needed. To do this, they used CRISPR / Cas9 technology, which allows you to change DNA fragments. For a living cell, any intervention is stress. Therefore, many times scientists have encountered a situation where the cell froze and stopped dividing.

“The development of a technique for transplanting an artificially grown embryo with gene correction into an animal is a large-scale and very laborious process. For several years, a huge amount of research work has been carried out on the selection of donor material, its preparation for editing, a serious bioinformatics analysis has been performed, a system for making changes to the genome based on CRISPR/Cas9 has been created, and its improved version, packaged in adeno-associated virus (AAV ). At each stage, something did not work, did not work, and we carefully looked for the cause. The key to the success of the project was a wonderful team - geneticists, embryologists, biologists and veterinarians involved in the study are highly qualified specialists," says Anna Sergeevna Krivonogova, project manager.

The project, unique on a national scale, is supervised by the Vice-President of the Russian Academy of Sciences I.M. Sweet clover. The project is being implemented at the Ural Federal Agrarian Research Center of the Ural Branch of the Russian Academy of Sciences together with the Center for High-precision Editing and Genetic Technologies for Biomedicine of the Institute of Gene Biology of the Russian Academy of Sciences, leading medical embryologists and Uralplemcenter JSC.

Today, scientists began research on the first experimental calf. In the near future, they will have to lay down the following experiments in order to bring the technology to perfection.