Option of method for accounting nuclear anomalies in birds erythrocytes

Analysis of the frequency of cells with micronucleus and other nuclear anomalies is a widely used method of oncological screening and assessment of the genetic hazard of environmental factors. This method is widely used to study the frequencies of cytogenetic anomalies in red blood cells of the peripheral blood of birds. At the same time, the criteria for detecting nuclear anomalies used by different researchers are rather vague. They use different names to denote the same anomalies and vice versa, different anomalies denote the same term. This situation makes it difficult to assess the mutagenic activity of factors, acting on birds in experimental conditions. It prevents a comparative analysis of the background frequencies of the nuclear anomalies in birds from natural populations and farm birds of different species, breeds and crosses. In this publication, the author made an attempt to systematize for the practical analysis the existing variety of names and descriptions of the nuclear anomalies in the bird erythrocytes. To prepare the publication, the author used personal experience in testing nuclear anomalies in the erythrocytes of birds, amphibians, and fishes. The guidelines for micronuclear testing of the animal and human cells, published earlier, were also taken into account. The presented version of the method for calculating the frequencies of micronucleus and other nuclear anomalies in bird erythrocytes suggests differentiating nuclear anomalies by five dimensional classes (> 0.1; 0.1-0.2; 0.21-0.33, 0.34-0, 5, 0.51-1.0) relative to the size of a normal cell nucleus. In addition, it is proposed to determinate the individual and total frequencies of the chromatin fragments that are completely separated from the main nucleus, adjacent to the nucleus, connected to the main nucleus by chromatin bridges, as well as morphological structures which chromatin is not separated from the chromatin of the main nucleus. This protocol can be used to calculate the nuclear anomalies in other animals whose erythrocytes contain the nucleus - fish, amphibians and reptiles.