Number Of Hybridization Events Research Articles

Гибридизация в эволюции человека

Materials and methods. Scientific literature to review was collected from the PubMed database (https://pubmed.ncbi.nlm.nih.gov), some other publications were collected from the open internet sources. Results. Herein we represent a review of current data for genetics regarding the hybridization events of the human evolution. The paper reviews ancient human interactions that had place 30-1000 thousands of years ago and could be detected by the methods of genetics. Both, divergence of the Old World human population and consequent introgression and hybridization processes that had led to the formation of modern human are analyzed. Discussion. The current genetics allows to study and analyze genomes of human and other animals in the aim to discover their evolutionary relationships. The consequent reveal of the ancient and extinct animal genomes allowed to speak about palaeogenetics, while the genome comparisons have formed a new discipline, comparative genomics, an analogue of the comparative anatomy. Modern and ancient human genomes' analysis have discovered the ancient human subpopulations' interactions and relations, part of which gave rise to the modern humans. Conclusion. Modern humans are a result of i) evolution of the isolated ancient human populations which had formed 200–1000 thousands of years ago; and ii) of interaction between them. Indeed, a number of hybridization events we can see during the human evolution, most of them are reflected in the modern and ancient human genomes.

Origins and Evolution in theAspidoscelis cozumelaComplex of Parthenogenetic Teiid Lizards: Morphological and Karyotypic Evidence and Paradoxes

Abstract The Aspidoscelis cozumela complex of parthenogenetic lizards of the Yucatan Peninsula originated from hybridization between individuals of Aspidoscelis angusticeps (maternal) and Aspidoscelis deppii deppii (paternal) followed by postorigin clonal divergence. A previous report of histocompatibility between two members of the complex, Aspidoscelis maslini and Aspidoscelis cozumela, is reliable evidence that they share a single hybridization event. However, evidence from mitochondrial DNA and histoincompatibility has been used to conclude that another member of the complex, Aspidoscelis rodecki, originated from a separate hybridization event. Although future evidence might tip the balance in favor of a two-hybridization model, we provide examples where evidence from mtDNA and histoincompatibility probably led to incorrect predictions of the number of hybridization events in parthenogenetic Aspidoscelis. In this study, we compared correspondence between patterns of morphological and karyotypic diverg...

Evidence for species differentiation within the Ancistrocladus tectorius complex (Ancistrocladaceae) in Southeast Asia: a molecular approach

Representatives of the genus Ancistrocladus, woody lianas of tropical Africa and Asia, contain pharmaceutically interesting alkaloids and have been the subjects of intensive phytochemical investigations. In Southeast Asia, Ancistrocladus tectorius, previously regarded as the only species of the genus from this region, is extremely polymorphic with respect to naphthylisoquinoline alkaloids, indicating that this taxon might be comprised of several morphologically similar species. We performed a comparative study of the ITS region of nuclear rDNA and of the trnK intron of cpDNA as well as an ISSR fingerprint analysis. Using 75 samples of A. tectorius from 21 locations in comparison to samples of other Ancistrocladus species from Asia and from West and Central Africa, we investigated patterns of species differentiation within this taxon. We found the high variability of chemical compounds described for A. tectorius to be paralleled by a high genetic variability of the units that have been assigned to this taxon. Samples assigned to A. tectorius were paraphyletic with respect to species from the Indian subcontinent, and intraspecific variability was comparable to interspecific variability among the African taxa. In addition, groups of individuals occurring in sympatry were found to be more similar to those from other locations, suggesting low levels of gene flow between those sympatric groups. This indicates either a considerable number of hybridization events during the evolution of A. tectorius or the existence of several distinguishable species not yet recognized. Our results are a first step in the development of species or population-specific markers for the prediction of the alkaloid spectrum of samples. This will help to improve the reproducibility of phytochemical research on Ancistrocladus.

Evolutionary and Systematic Implications of Skin Histocompatibility Among Parthenogenetic Teiid Lizards: Three Color Pattern Classes of Aspidoscelis dixoni and One of Aspidoscelis tesselata

Abstract The whiptail lizard Aspidoscelis dixoni (Teiidae) comprises three distinctive color pattern classes (i.e., variants); A and B are restricted to Presidio County, Texas, and C is isolated over 500 km to the west-northwest in Hidalgo County, New Mexico. Pattern class E of A. tesselata is widely distributed in Chihuahua, Texas, and New Mexico. Genetic data have verified that these parthenogenetic species are hybrid-derivatives of A. tigris marmorata ♀ X A. gularis septemvittata ♂; however, the number of hybridization events involved in their origin has remained problematic. We used 19 lizards in laboratory skin-grafting experiments to test the histoincompatibility responses among A. dixoni A, B, C, and A. tesselata E. The results of these graft exchanges indicated that individuals of all four pattern classes were mutually histocompatible to skin grafts, a level of genetic homogeneity indicative of the origin of A. dixoni and A. tesselata from the same hybrid lizard. Thus, the color pattern variants A...