Ontogenes and Their Role in Cellular Construction

The genes referred to as ontogenes are responsible for conditional mutations. Based on the results of the research of conditional mutations in D. melanogaster, we attempt to figure out the biological role of ontogenes. We conclude that ontogenes in the process of individual development control the construction of the living organisms of cells (cellular construction), which comprises the induction of cell division, determination of division plane, and the location of daughter cells after the division is completed. The process of morphogenesis consists of cellular construction and protein synthesis. Protein synthesis is controlled by protein-coding (Mendelian) genes. Mendelian genes are switched on by ontogenes. In terms of the two-component genome composed of Mendelian genes and ontogenes, we consider 1) the concept of biological character;2) interspecific incompatibility;3) ontogenesis;4) phylogenesis;and 5) mutagenesis. Ontogenes, which control cellular construction, possess the specific features unusual for Mendelian genes, namely, 1) the activity in germ line tissue;2) remote interaction;and 3) activity in a compacted state (heterochromatization). These specific features of ontogenes suggest that unlike the Mendelian genes with their chemical activity, ontogenes possess another type of activity (biophysical) involving induction of an electromagnetic field.

Mutation in Ontogene and Emergence of Secondary Chromosome Damages in Drosophila Germline Cells

The conditional mutations in drosophila were obtained by γ-irradiation and selected using the test for dominant lethality. The conditional mutations survive under permissive genetic conditions and, additionally, commence to display novel properties. One of such properties is a recessive lethality. Ten conditional mutations that displayed recessive lethality were mapped with the help of a standard set of deletions. Half mutations contained two and more lethal defects. The fact that a large number of the lethal defects are associated with one mutation suggests that γ-irradiation is the most unlikely cause of the defects. One of the conditional mutations carried four lethal regions and had a Small barrel (Smba) visual phenotype. The Smba phenotype in the Smba/ In(2LR) Cy strain is inherited according to a parental type and disappears in the Smba/In(2LR) Pm strain. Lethality in two of the four lethal regions also disappears in this strain. A separate experiment was conducted to clarify how these regions lost a lethal manifestation after the In(2LR) Cy chromosome in the Smba/In(2LR) Cy strain was replaced with the In(2LR) Pm chromosome. The process of disappearance of the Smba phenotype was also observed in three Smba/In(2LR) Cy substocks. These data suggest that the regions of multiple recessive lethality emerge in a secondary manner under the effect of the earlier formed radiation-induced mutation in ontogene. It is assumed that the recessive lethal regions are the ontogenes with an altered DNA conformation. The conformation in ontogenes is changed in the germline cells during a regular “editing” of the individual development program.

Ontogenes and the Paradox of Homologous Pairing

The mutations in ontogenes have been shown to drastically increase the nondisjunction of X chromosomes in the D. melanogaster meiosis. This means that ontogenes are involved in the process that brings the homologs together although both the genes and ontogenes are finally paired. The phenomenon named the paradox of homologous pairing is described. Chromosomal rearrangements (inversions and translocations) lead to formation of specific topological figures (loops and crosses) during pairing. The mutual arrangement of the nucleotide sequences of homologous ontogenes before and after formation of such figures is different. Their arrangement coincides after a figure is formed and the pairing looks homologous. However, before the figure is formed, their arrangement does not match and the pairing is actually nonhomologous. The available data on ontogenes allows this paradox to be resolved. It is assumed that the sequence of each ontogene possesses a factor that 1) is a product of this nucleotide sequence;2) is co-located with this sequence;and 3) generates approaching independently of nucleotide sequence position in space. The sole candidate to the role of this factor is the DNA conformation of ontogene. The conformation in the form of a solenoid of DNA is able to generate an electromagnetic field independent of the orientation of the DNA itself. The proposed resolution of the paradox is considered in terms of the problem of genetic homology.

Ontogenes and Chromosome Nondisjunction in the D. melanogaster Meiosis

A mutation in an ontogene acts as a conditional dominant lethal: it is lethal in a certain genotype but not lethal in another. In total, 30 mutations of this type residing in the Drosophila melanogaster X chromosome have been assayed for their ability to cause meiotic nondisjunction. The level of X nondisjunction in the females heterozygous for the mutation in ontogene appears to be very high. The share of matroclinous daughters reaches 24.7% of the overall offspring and of patroclinous males, 24.9%. Neither inversion in the opposite X chromosome nor additional Y chromosome has any effect on the X nondisjunction. The balance of the XX and X0 egg cells is disturbed: exceptional daughters are prevalent in the offspring of the females with a normal opposite X chromosome and exceptional sons, in the offspring of the females with an inverted X chromosome. In addition, 12% of the matroclinous daughters of the females with a normal opposite X chromosome are homozygous for the marker of one of the maternal X chromosomes (“equational” nondisjunction). A “fading” parental effect of the mutation in ontogene on the X chromosome nondisjunction is also observed. Under experimental conditions, the mutant ontogenes reside in meiotic densely compacted X chromosomes. We infer that the ontogenes are DNA regions with controlled compaction. It is postulated that the genetic activity of ontogenes is determined by this compaction and has a biophysical (electromagnetic) nature. In a meiotic cell, ontogenes induce physical fields providing the operation of meiotic proteins. The structure of these fields is distorted in the mutants for ontogenes, thereby decreasing the efficiency of proteins and, as a consequence, causing meiotic defects.

Conditional Mutations in Drosophila: Concept of Genes That Control Individual Development

The conditional mutations in D. melanogaster are produced by gamma-irradiation, maintained in laboratory cultures, and inherited as gene mutations. However, their manifestation differs from the conventional mutations by several specific features. The most noticeable specific feature is their conditional nature, i.e., a conditional mutation manifests itself in the individuals of a certain genotype being silent in the individuals with another genotype. A particular procedure for mutation recovery determines what these genotypes will be. An overwhelming number of mutations are conditional dominant lethals. The viable mutation carriers display a drastically decreased fertility. Early zygotic lethality is inherited according to parental type (maternal or paternal). The carriers of conditional mutations give the offspring with a high rate of monstrosities. The possibility for the offspring to form monstrosities is inherited according to a parental (maternal or paternal) type. The level of fertility of conditional mutants is altered by chromosomal rearrangements. The chromosomal rearrangements themselves cause a decrease in fertility. Lethality of the progenies produced by the parents carrying rearrangements is inherited according to a parental (maternal or paternal) type. The results allow for a set of logical arguments in favor of that 1) the genome has a specialized system of genes (ontogenes) that control the course of individual development;2) unlike a classical gene, acting according to the scheme DNA à RNA à protein, the ontogene implements the regulation according to the scheme DNA à RNA;and 3) the course of individual development is programmed by double-strand RNAs produced by ontogenes in germline cells.

Mesenchymal Stromal Cells Derived from Human Embryonic Stem Cells, Fetal Limb and Bone Marrow Share a Common Phenotype but Are Transcriptionally and Biologically Different

Mesenchymal stromal cells (MSCs) can be obtained from several sources and the significant differences in their properties make it crucial to investigate the differentiation potential of MSCs from different sources to determine the optimal source of MSCs. We investigated if this biological heterogeneity in MSCs from different sources results in different mechanisms for their differentiation. In this study, we compared the gene expression patterns of phenotypically defined MSCs derived from three ontogenically different sources: Embryonic stem cells (hES-MSCs), Fetal limb (Flb-MSCs) and Bone Marrow (BM-MSCs). Differentially expressed genes between differentiated cells and undifferentiated controls were compared across the three MSC sources. We found minimal overlap (5% - 16%) in differentially expressed gene sets among the three sources. Flb-MSCs were similar to BM-MSCs based on differential gene expression patterns. Pathway analysis of the differentially expressed genes using Ingenuity Pathway Analysis (IPA) revealed a large variation in the canonical pathways leading to MSC differentiation. The similar canonical pathways among the three sources were lineage specific. The Flb-MSCs showed maximum overlap of canonical pathways with the BM-MSCs, indicating that the Flb-MSCs are an intermediate source between the less specialised hES-MSC source and the more specialised BM-MSC source. The source specific pathways prove that MSCs from the three ontogenically different sources use different biological pathways to obtain similar differentiation outcomes. Thus our study advocates the understanding of biological pathways to obtain optimal sources of MSCs for various clinical applications.

Morphology and ontogeny of directly differentiating shoot buds and somatic embryos in Santalum album L.

Santalum album L.is a commercially important tree that yields essential oil of high medicinal value.Regeneration research through organogenesis and embryogenesis has been documented but no report depicts comparative ontogeny of directly differentiating shoot buds(SB)and somatic embryos(SE).In the present study aseptic seedling derived hypocotyl segments(HC)and hypocotyl+root junction(HC+R)were used to induce SBs and SEs,respectively.Ontogenic differences between the structures were confirmed using scanning electron microscopy and histological analysis.MS medium containing 6-benzyladenine or BA(2.5μM)produced highest number of direct SB,while MS+BA(7.5μM)proved suitable for higher frequency of SE differentiation.The differentiating structures attained growth when transferred to MS medium containing a combination of BA and anaphthalene acetic acid or silver nitrate(AgNO3).A combination of indole-3-butyric acid and silver nitrate(AgNO3)in half-strength woody plant medium and lesser osmotic concentration(2%sucrose),induced rhizogenesis.

Impact of obese levels on the hepatic expression of nuclear receptors and drug-metabolizing enzymes in adult and offspring mice

The prevalence of obesity-associated conditions raises new challenges in clinical medication.Although altered expression of drug-metabolizing enzymes(DMEs)has been shown in obesity,the impacts of obese levels(overweight,obesity,and severe obesity)on the expression of DMEs have not been elucidated.Especially,limited information is available on whether parental obese levels affect ontogenic expression of DMEs in children.Here,a high-fat diet(HFD)and three feeding durations were used to mimic different obese levels in C57BL/6 mice.The hepatic expression of five nuclear receptors(NRs)and nine DMEs was examined.In general,a trend of induced expression of NRs and DMEs(except for Cyp2c29 and 3a11)was observed in HFD groups compared to low-fat diet(LFD)groups.Differentialeffects of HFD on the hepatic expression of DMEs were found in adult mice at different obese levels.Family-based dietary style of an HFD altered the ontogenic expression of DMEs in the offspring older than 15 days.Furthermore,obese levels of parental mice affected the hepatic expression of DMEs in offspring.Overall,the results indicate that obese levels affected expression of the DMEs in adult individuals and that of their children.Drug dosage might need to be optimized based on the obese levels.