Open Access Pub publishes peer-reviewed, free-to-read open-access articles. Showing
articles matching speciation — open any to read the full text,
or download the PDF or XML.
Mar 2024 DOI 10.14302/issn.2689-4602.jes-24-4956
Chadov B.F.Corresponding author
A new type of mutations-dominant lethals with a facultative manifestation -were discovered in D. melanogaster in 2000. These mutations were named conditional mutations. Under restrictive genetic conditions, the mutations manifest themselves as dominant lethals, whereas dominant lethality disappears under permissive conditions, displaying a set of other manifestations. The genes responsible for the emergence of conditional mutations were named ontogenes. The experiments with mutations in ontogenes have revealed the following processes: (1) genome editing in germline cells; (2) induction of high mutagenesis rates in germline cells of the mutants for ontogenes; (3) zygotic selection; (4) isolation of mutants; and (5) alterations in the lethality of mutants with time. The specific features in the manifestation of ontogenes together with the listed processes formed the background for construction of the model of speciation named the regeneration model. The event of speciation is represented as the regeneration of the working state of a genetic system disturbed by the emergence of a mutation in an ontogene. According to the model, it is ontogenes that are in charge of speciation and, eventually, the structure of living matter in the form of individual species. The significance of Mendelian protein-coding genes and Darwinian selection of the fittest according to these genes are doubtless but not paramount.
Feb 2019 DOI 10.14302/issn.2689-4602.jes-18-2431
F Chadov BorisCorresponding author
Institute of Cytology and Genetics, Siberian Department of Russian Academy of Sciences, Novosibirsk 630090, Russian Federation.
The existing hypotheses on speciation rely on Mendelian genes and mutations in them. However, genome-wide sequencing demonstrates that the Mendelian genes account less than one-tenth of the entire genome DNA. This means that a greater part of the genome has not yet been subject to large-scale evolutionary consideration. This paper deals with the conditional mutations in drosophila, which are mutations of the genes belonging to a special category (ontogenes) controlling the program of individual development. The ontogenes presumably reside in the DNA of intergenic spaces and introns. Conditional mutations display a number of properties absent in the mutations of Mendelian genes. These specific properties allow three key problems in speciation to be solved: (1) the possibility of emergence of new traits as a result of sequential mutagenesis; (2) selection of mutants; and (3) establishment of isolation. We have shown that (1) the mutations in ontogenes are able to form new multigenic regulatory blocks that escape selection during their creation; (2) mutations in ontogenes allow for existence of constantly acting zygotic selection, which is by no means less important for speciation than Darwinian selection; and (3) owing to their conditionally lethal effect, the mutations in ontogenes are able to create biological isolation barrier. This gives the grounds for assuming that the emergence of mutations in ontogenes is a necessary condition for speciation.
Jan 2019 DOI 10.14302/issn.2643-0282.imsj-18-2514
Fadel Madkour FedekarCorresponding author
Marine Science Department, Faculty of Science, Port Said University, Port Said, Egypt
The Anthomedusae species, Corymorpha bigelowi Maas, 1905 (Cnidaria: Hydrozoa, Corymorphidae), was recorded in the northern Red Sea fauna, representing it "first invasion" in Egypt. A fact proven by past studies that this species is endemic in the Indo-Pacific region, which is mainly located in southern coast of Japan and Indian Ocean. The specimens were collected from an area located off Hurghada city, and between latitudes 27° 14.427ˊ and 27° 10.816ˊ N, and longitudes 33° 51.085ˊ and 33° 51.603ˊ E using plankton net (350 µm mesh). In total, six mature medausae of C. bigelowi were caught in December 2014 and February 2015 (4 and 2 medusae, respectively). Following this, the captured species medusa of C. bigelowi was photographed and morphological characteristics described in details. As well as, further discussions of biogeographical distribution and morphological speciation of the present species were provided. This work makes a noteworthy contribution to clarify the migration route of C. bigelowi from southern Red Sea to the Mediterranean Sea. nih.gov/pmc/articles/PMC3155160/
Apr 2016 DOI 10.14302/issn.2575-7881.jdrr-15-863
A. Fuertes MiguelCorresponding author
Centro de Biología Molecular ‘‘Severo Ochoa’’ (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.
It was, previously, reported that the specific pattern of the compositional features of particular human-mouse orthologs defining in human two clusters, named C2 and C5, are present in different clusters in mouse. Since, thus, these orthologs can harbor a significant number of nucleotide differences a large sample of human-mouse orthologs having in human the C2 and C5 compositional features were collected in order to identify the orthologs that have been conserved or diverged during speciation. From the collection, 945 and 1051 orthologs had in human the C2 and C5 profile, respectively, while in mouse only 77 and 125, respectively, had these profiles. We further analyzed whether or not the frequency-usage of trinucleotides having the same gross composition computed from the reading of all nearest-neighbors of the DNA sequence might convey a layer of biological information in terms of chromosomal topology and function. In human, more than 50% of the C2 and C5 genes were found distributed in six chromosomes and preferentially located in GC-rich bands of chromosomes 11, 16 and 19. It was, also, found that 80% of the entire set of genes of band 19p13.3 had the C2 and C5 profile. The data shown also indicate that the proteins codified by the C5 genes have a bias towards nucleus and cytoplasm and specific post-translational modifications while the proteins codified by the C2 genes are mainly located in the cellular membrane or secreted to the external cellular milieu and particular post-transcriptional modifications