scholarly journals CHROMOSOMAL REARRANGEMENTS AND THE GENETICS OF REPRODUCTIVE BARRIERS INMIMULUS(MONKEY FLOWERS)

Evolution ◽  
2013 ◽  
Vol 67 (9) ◽  
pp. 2547-2560 ◽  
Author(s):  
Lila Fishman ◽  
Angela Stathos ◽  
Paul M. Beardsley ◽  
Charles F. Williams ◽  
Jeffrey P. Hill
Keyword(s):  
Chromosomal Rearrangements ◽  
Reproductive Barriers

Hybrid Zones and the Genetic Architecture of a Barrier to Gene Flow Between Two Sunflower Species

Genetics ◽  
1999 ◽  
Vol 152 (2) ◽  
pp. 713-727 ◽  
Author(s):  
Loren H Rieseberg ◽  
Jeannette Whitton ◽  
Keith Gardner
Keyword(s):  
Genetic Study ◽  
Genetic Architecture ◽  
Chromosomal Rearrangements ◽  
Pollen Sterility ◽  
Model Organisms ◽  
Hybrid Zones ◽  
Reproductive Barriers ◽  
Natural Hybrid ◽  
Generation Times ◽  
Helianthus Petiolaris

Abstract Genetic analyses of reproductive barriers represent one of the few methods by which theories of speciation can be tested. However, genetic study is often restricted to model organisms that have short generation times and are easily propagated in the laboratory. Replicate hybrid zones with a diversity of recombinant genotypes of varying age offer increased resolution for genetic mapping experiments and expand the pool of organisms amenable to genetic study. Using 88 markers distributed across 17 chromosomes, we analyze the introgression of chromosomal segments of Helianthus petiolaris into H. annuus in three natural hybrid zones. Introgression was significantly reduced relative to neutral expectations for 26 chromosomal segments, suggesting that each segment contains one or more factors that contribute to isolation. Pollen sterility is significantly associated with 16 of these 26 segments, providing a straightforward explanation of why this subset of blocks is disadvantageous in hybrids. In addition, comparison of rates of introgression across colinear vs. rearranged chromosomes indicates that close to 50% of the barrier to introgression is due to chromosomal rearrangements. These results demonstrate the utility of hybrid zones for identifying factors contributing to isolation and verify the prediction of increased resolution relative to controlled crosses.

HYBRID STERILITY AS A REPRODUCTIVE BARRIER ISOLATING THE TWO SUBSPECIES OF AEGILOPS GENICOLATA ROTH (GRAMINEAE)

1999 ◽  
Vol 47 (2) ◽  
pp. 89-95 ◽  
Author(s):  
Shoji Ohta
Keyword(s):  
Hybrid Sterility ◽  
Chromosomal Rearrangements ◽  
Reproductive Barrier ◽  
Reproductive Barriers ◽  
Polyploid Species ◽  
Negative Interaction ◽  
Aegilops Geniculata ◽  
Chromosome Differentiation ◽  
Infraspecific Taxa ◽  
Mother Cells

To detect possible reproductive barriers isolating the two subspecies of Aegilops geniculata, ssp. gibberosa was crossed with ssp. geniculata. The two subspecies differ significantly in shape of spikes, spikelet density on spikes, and number of awns on empty glumes. The F hybrids were intermediate in morphology and almost completely sterile. A chromatid bridge with a fragment was observed at first anaphase (AI) of meiosis in some pollen mother cells (PMCs) of the F1 hybrids. Though multivalents were formed at first metaphase (MI) in all the PMCs of the F1 hybrids, the frequency was not higher than that in the intra-subspecific hybrids of ssp. geniculata. These results suggest that the intraspecific sterility is not caused by a gross chromosome differentiation. The hybrid sterility, which is an effective reproductive barrier isolating the two subspecies, might be caused by negative interaction(s) between genes of the two subspecies, or by small chromosomal rearrangements not detectable from chromosome pairing configuration at MI. It is strongly proposed that the delineation of species and infraspecific taxa in the polyploid species of the genus Aegilops is worthy of reassessment from a biosystematic viewpoint.

Electron Microscopy and image analysis of nucleo-protein complexes

1994 ◽  
Vol 52 ◽  
pp. 88-89
Author(s):  
E. H. Egelman ◽  
X. Yu
Keyword(s):  
Electron Microscopy ◽  
Image Analysis ◽  
Normal Cell ◽  
Genetic Recombination ◽  
Protein Complexes ◽  
Chromosomal Rearrangements ◽  
Reca Protein ◽  
E Coli ◽  
Helical Polymer ◽  
Specific Protease

The RecA protein of E. coli has been shown to mediate genetic recombination, regulate its own synthesis, control the expression of other genes, act as a specific protease, form a helical polymer and have an ATPase activity, among other observed properties. The unusual filament formed by the RecA protein on DNA has not previously been shown to exist outside of bacteria. Within this filament, the 36 Å pitch of B-form DNA is extended to about 95 Å, the pitch of the RecA helix. We have now establishedthat similar nucleo-protein complexes are formed by bacteriophage and yeast proteins, and availableevidence suggests that this structure is universal across all of biology, including humans. Thus, understanding the function of the RecA protein will reveal basic mechanisms, in existence inall organisms, that are at the foundation of general genetic recombination and repair.Recombination at this moment is assuming an importance far greater than just pure biology. The association between chromosomal rearrangements and neoplasms has become stronger and stronger, and these rearrangements are most likely products of the recombinatory apparatus of the normal cell. Further, damage to DNA appears to be a major cause of cancer.

The experience of holding the cycles of assisted reproductive technology with defrost, a biopsy, genetic study and refreezing of embryos in patients with multiple unsuccessful implantations

2016 ◽  
pp. 166-170
Author(s):  
Y.V. Masliy ◽  
◽  
I.O. Sudoma ◽  
P.S. Mazur ◽  
D.A. Mykytenko ◽  
...  
Keyword(s):  
Chromosomal Rearrangements ◽  
Genetic Diagnosis ◽  
Morphological Characteristics ◽  
Implantation Rate ◽  
Ovarian Response ◽  
Reproductive Technologies ◽  
Comparative Genome Hybridization ◽  
Comparative Genome ◽  
Vitro Fertilization

The objective: to study the possibility of using frozen blastocysts for biopsy and genetic testing and performance measurement transfer euploeded 5–7-day-old embryos after thawing, biopsies, refreezing and thawing in patients with unsuccessful implantation. Patients and methods. The object of the study was the group of patients with repeated failure of implantation (4) in programs of auxiliary reproductive technologies (ART), subject to transfer to the uterus in total (i.e. in all the programs) for at least 6 good quality embryos based on morphological characteristics). All women had sufficient ovarian reserve. The patient was treated for infertility within the ART programs of the clinic of reproductive medicine "Nadiya" in the period from 2006 to 2016. The sample included couples who were not carriers of chromosomal rearrangements, without anomalies of the uterus (congenital and acquired: a doubling of the uterus, one-horned uterus, intrauterine membrane, synechia, submucous myoma of the uterus). All women had a positive ovarian response to controlled stimulation with gonadotropins (at least 7 oocytes) and a sufficient number of cryopreserved embryos. The first group (G1) included 64 women who trophectodermal a biopsy was performed on fresh blastocysts (in a loop controlled ovarian hyperstimulation). The second group (G2) were included 31 women who underwent thawing previously cryopreserved blastocysts trophectodermal re-biopsy and vitrification of blastocysts. Results. It was found that the performance of transfers euploid embryos that were vitrified, bioptrone and revitriphted, a little lower than those that were bioptrone fresh and vitrified only once. At the same time computationa genetic diagnosis previously vitrified blastocysts using comparative genome hybridization in patients with recurrent failed implantation allows to obtain a reasonable pregnancy rate (58%), implantation rate (33.3 %) and the birth of living children (45.1 %). Conclusion. Reprising biopropane embryos does not cause significant destructive impact and allows you to achieve pregnancy and birth of the alive child. Key words: in vitro fertilization, reusable unsuccessful implantation, a method of comparative genome hybridization, refreezing.

Quantitative Evaluation of Chromosomal Rearrangements in Primary Gene-Edited Human Stem Cells by Preclinical CAST-Seq

2020 ◽  
Author(s):  
Giandomenico Turchiano ◽  
Geoffroy Andrieux ◽  
Georges Blattner ◽  
Valentina Pennucci ◽  
Julia Klermund ◽  
...  
Keyword(s):  
Stem Cells ◽  
Quantitative Evaluation ◽  
Chromosomal Rearrangements ◽  
Human Stem Cells ◽  
Primary Gene

Cerebellotrigeminal Dermal Dysplasia (Gómez-López-Hernández Syndrome)

2018 ◽  
Vol 16 (05) ◽  
pp. 362-368 ◽  
Author(s):  
Federica Sullo ◽  
Agata Polizzi ◽  
Stefano Catanzaro ◽  
Selene Mantegna ◽  
Francesco Lacarrubba ◽  
...  
Keyword(s):  
De Novo ◽  
Chromosomal Rearrangements ◽  
Number Of Patients ◽  
Wide Range ◽  
Visual Problems ◽  
Neurodevelopmental Abnormalities ◽  
Clinical Triad ◽  
High Degree ◽  
Motor Handicap

Cerebellotrigeminal dermal (CTD) dysplasia is a rare neurocutaneous disorder characterized by a triad of symptoms: bilateral parieto-occipital alopecia, facial anesthesia in the trigeminal area, and rhombencephalosynapsis (RES), confirmed by cranial magnetic resonance imaging. CTD dysplasia is also known as Gómez-López-Hernández syndrome. So far, only 35 cases have been described with varying symptomatology. The etiology remains unknown. Either spontaneous dominant mutations or de novo chromosomal rearrangements have been proposed as possible explanations. In addition to its clinical triad of RES, parietal alopecia, and trigeminal anesthesia, CTD dysplasia is associated with a wide range of phenotypic and neurodevelopmental abnormalities.Treatment is symptomatic and includes physical rehabilitation, special education, dental care, and ocular protection against self-induced corneal trauma that causes ulcers and, later, corneal opacification. The prognosis is correlated to the mental development, motor handicap, corneal–facial anesthesia, and visual problems. Follow-up on a large number of patients with CTD dysplasia has never been reported and experience is limited to few cases to date. High degree of suspicion in a child presenting with characteristic alopecia and RES has a great importance in diagnosis of this syndrome.

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