The bystander effect formation in the meristem of Allium cepa L. plants with different genotype

Aim. Obtaining and analysis of cytogenetic parameters in meristem cells of Allium cepa L. seedling sprouting from unirradiated seeds, while germinating them with seeds, that were exposed to γ-radiation in different doses. Methods. Cytogenetic analysis included analysis of mitotic activity, anaphase method of chromosome mutations, nucleolar analysis. The F-test was used to compare the control and experimental samples. Results. The formation of the bystander effect is shown in the case of joint germination of irradiated and non-irradiated seeds. The severity of bystander effect increases with increasing irradiation dose. Conclusions. Irradiation of seeds with a dose of gamma radiation of 40 Gy causes the formation of radiation hormesis by the criterion of mitotic activity in the root meristem cells of seedlings, and the irradiation with a dose of 10 Gy does not affect the level of cell proliferation. The bystander effect formation occurs during the joint germination of intact and irradiated seeds as an increase in the level of mitotic activity, and an increase in the number of chromosomal mutations. Keywords: bystander effect, γ-radiation, meristem, mitotic activity, chromosomal abnormalities, micronuclei.

Mutation Rate Variability across Human Y-Chromosome Haplogroups

A common assumption in dating patrilineal events using Y-chromosome sequencing data is that the Y-chromosome mutation rate is invariant across haplogroups. Previous studies revealed interhaplogroup heterogeneity in phylogenetic branch length. Whether this heterogeneity is caused by interhaplogroup mutation rate variation or nongenetic confounders remains unknown. Here, we analyzed whole-genome sequences from cultured cells derived from >1,700 males. We confirmed the presence of branch length heterogeneity. We demonstrate that sex-chromosome mutations that appear within cell lines, which likely occurred somatically or in vitro (and are thus not influenced by nongenetic confounders) are informative for germline mutational processes. Using within-cell-line mutations, we computed a relative Y-chromosome somatic mutation rate, and uncovered substantial variation (up to 83.3%) in this proxy for germline mutation rate among haplogroups. This rate positively correlates with phylogenetic branch length, indicating that interhaplogroup mutation rate variation is a likely cause of branch length heterogeneity.

Karyological and cytogenetic research of the conifers of boreal zone by classic and new methods

Aim. Establishing of karyological features and conducting of cytogenetic analysis on conifer plants for biological diversity studies, solving of problems of taxonomics, evolutionary and population genetics. Methods. Classic methods with acetohematoxylin staining of slides and fluorescent in situ hybridization (FISH). Results. More than 150 populations and provenances of representatives of different conifer genera from the Pinaceae and Cupressaceae families were studied. The studies were carried out in natural populations and during the introduction, in optimal and extreme conditions, in disturbed ecosystems, botanical gardens and parks; in addition, various intraspecific forms have been studied. The variability of chromosome numbers and a wide range of chromosomal mutations have been revealed. Fluorescence in situ hybridization (FISH) with the 45S and 5S ribosomal RNA gene probes and DAPI staining allows to identify of homologous chromosome pairs in the karyotypes of conifers and to facilitate the comparative karyotype analysis of these species. Conclusions. The studies of chromosomes in species of the Pinaceae and Cupressaceae families showed a karyotypic diversity and chromosomal anomalies in extreme conditions and under introduction. The use of molecular cytogenetic markers made it possible to obtain new information on the structure of conifer chromosomes. Keywords: chromosomes, nucleolar loci, chromosome mutations, Pinaceae, Cupressaceae.

Moderate the MAOA-L Allele Expression with CRISPR/Cas9 System

Antisocial behavior is a behavior disorder inherited according to the inheritance of X-linked chromosome. Mutations in the MAOA gene can cause different behaviors in humans. These can comprise violent behavior or antisocial behavior. Low MAOA (MAOA-L) allele activity can cause antisocial behavior in both healthy and unhealthy people. Antisocial from healthy males can originate from maltreatment during childhood. There are no drugs for the treatment of antisocial behavior permanently at this time. MAOA inhibitor can reverse antisocial behavior in animal models. To cure antisocial behavior in the future, the CRISPR/Cas9 system in combination with iPSCs or ssODN methods for instance can be used. This system has succeeded to correct erroneous segments in the F8 gene and F9 gene. Both genes occupy the X chromosome. The MAOA gene also occupies the X chromosome. It seems that CRISPR/Cas9 system may be a beneficial tool to edit erroneous segments in the MAOA gene to treat antisocial behavior.

Molecular Cytogenetics in the Diagnostics of Balanced Chromosome Mutations in the Pig (Sus scrofa) – A Review

Continually improved cytogenetic techniques (differential staining and high resolution banding techniques), complemented with the molecular genetics methods (FISH and PRINS), enable chromosomal mutations to be accurately identified in the karyotype of the pig (Sus scrofa). The major breeding problem are balanced mutations because of their hidden nature, as they affect the animals with normal body conformation (and normal semen parameters in boars), which transfer these aberrations to the next generations and disseminate in the population. This refers to the structural rearrangements (translocations and inversions), causing developmental abnormalities and considerably reducing fertility and productivity parameters in breeding herds, which results in substantial financial losses. Routine karyotype screening using modern cytomolecular diagnostic methods is necessary due to the potential emergence of new mutations and the rapid spread of these genetic defects in the population, especially under artificial insemination conditions.