scholarly journals Meiotic drive of female-inherited supernumerary chromosomes in a pathogenic fungus

2018 ◽  
Author(s):  
Michael Habig ◽  
Gert H.J. Kema ◽  
Eva H. Stukenbrock
Keyword(s):  
Chromosome Segregation ◽  
Pathogenic Fungus ◽  
Female Parent ◽  
Meiotic Drive ◽  
Mendelian Inheritance ◽  
Feedback Mechanism ◽  
Zymoseptoria Tritici ◽  
Supernumerary Chromosomes ◽  
Meiotic Transmission ◽  
Additional Feedback

AbstractMeiosis is a key cellular process of sexual reproduction involving the pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungus Zymoseptoria tritici that possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired. Unpaired chromosomes inherited from the male parent as well as paired supernumerary chromosomes showed Mendelian inheritance. In contrast, unpaired chromosomes inherited from the female parent showed non-Mendelian inheritance but were amplified and transmitted to all meiotic products. We concluded that the supernumerary chromosomes of Z. tritici show a meiotic drive and propose an additional feedback mechanism during meiosis which initiates amplification of unpaired female-inherited chromosomes.

scholarly journals Meiotic drive of female-inherited supernumerary chromosomes in a pathogenic fungus

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Michael Habig ◽  
Gert HJ Kema ◽  
Eva Holtgrewe Stukenbrock
Keyword(s):  
Chromosome Segregation ◽  
Pathogenic Fungus ◽  
Female Parent ◽  
Meiotic Drive ◽  
Mendelian Inheritance ◽  
Feedback Mechanism ◽  
Zymoseptoria Tritici ◽  
Supernumerary Chromosomes ◽  
Meiotic Transmission ◽  
Additional Feedback

Meiosis is a key cellular process of sexual reproduction that includes pairing of homologous sequences. In many species however, meiosis can also involve the segregation of supernumerary chromosomes, which can lack a homolog. How these unpaired chromosomes undergo meiosis is largely unknown. In this study we investigated chromosome segregation during meiosis in the haploid fungus Zymoseptoria tritici that possesses a large complement of supernumerary chromosomes. We used isogenic whole chromosome deletion strains to compare meiotic transmission of chromosomes when paired and unpaired. Unpaired chromosomes inherited from the male parent as well as paired supernumerary chromosomes in general showed Mendelian inheritance. In contrast, unpaired chromosomes inherited from the female parent showed non-Mendelian inheritance but were amplified and transmitted to all meiotic products. We concluded that the supernumerary chromosomes of Z. tritici show a meiotic drive and propose an additional feedback mechanism during meiosis, which initiates amplification of unpaired female-inherited chromosomes.

scholarly journals Microsatellite Genetic Markers of Saccharrum spp., and Erianthus sp. on Their Hybrids

2019 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Mala Murianingrum ◽  
Taryono Taryono ◽  
Rani Agustina Wulandari
Keyword(s):  
Molecular Marker ◽  
Genetic Marker ◽  
Genetic Markers ◽  
Chromosome Segregation ◽  
Molecular Genetic ◽  
Female Parent ◽  
Limiting Factors ◽  
Phenotypic Characteristics ◽  
Saccharum Spp ◽  
Sugarcane Varieties

Progeny identification is the important step that should be done after hybridization. However, polyploidy, aneuploidy and the high chromosome segregation in sugarcane which results various phenotypic characteristics variation and environmental effects become limiting factors to identify the progenies based on morphological characteristic. Microsatellite as one of molecular marker which has codominance inheritance, multiallelic, abundant in the genome and does not influenced by environmental factor is the best tool to asses the crossing fidelity accurately. This research aimed to identify the possibility of genetic marker of Saccharum spp. and Erianthus sp. on their hybrid using microsatellite molecular marker. This study was carried out in Molecular Genetic laboratory, Indonesian Sweetener and Fiber Crops Research Institute (ISFCRI) Malang, from August 2016 to July 2017. Eighty-six (86) F1 intraspecific and interspecific progeny, three commercial sugarcane varieties (PSJT941, PS881 and VMC7616) and two wild types (S. spontaneum dan Erianthus sp.) were assessed genetically by three microsatellite markers. Identification of microsatellite genetic markers was conducted by comparing the visualization band results from electrophoresis of each male and female parent through their progenies. All primers could identify Saccharum spp. and Erianthus sp. genetic markers. There were one to eleven Saccharum spp. and Erianthus sp. genetic markers could be identified such as 2-11 PS881-specific alleles; 2-3 VMC7616-specific alleles; 1-5 PSJT941-specific alleles; two S. spontaneum-specific alleles and 1-2 Erianthus-specific alleles. These findings could be used as the advance genetic marker of microsatellite in sugarcane breeding to asses the cross fidelity.

Segregation of random amplified polymorphic DNA markers and strategies for molecular mapping in tetraploid alfalfa

Genome ◽  
1993 ◽  
Vol 36 (5) ◽  
pp. 844-851 ◽  
Author(s):  
K. F. Yu ◽  
K. P. Pauls
Keyword(s):  
Chromosome Segregation ◽  
Dna Markers ◽  
Rapd Markers ◽  
Molecular Mapping ◽  
Random Amplified Polymorphic Dna ◽  
Rapd Marker ◽  
Female Parent ◽  
Linkage Groups ◽  
Double Reduction ◽  
Chromatid Segregation

An F1 population was used to analyze the inheritance of random amplified polymorphic DNA (RAPD) markers in tetraploid alfalfa. Of the 32 RAPD markers that were used for a segregation analysis in this study, 27 gave ratios that are consistent with random chromosome and random chromatid segregation at meiosis. However, among all of the RAPD markers (121) that were screened in this study, only one example of a double reduction, that is typical of chromatid segregation, was observed. These results indicate that random chromosome segregation is likely the predominant but not the exclusive mode of inheritance for tetraploid alfalfa. χ2 analyses of cosegregation for RAPD marker pairs derived from the female parent revealed nine linkages that fell into four linkage groups. The recombination fractions among linked marker pairs ranged from 1 to 37%. These are the first molecular linkage groups reported in tetraploid alfalfa. In addition, various strategies for molecular mapping in the tetraploid alfalfa genome are proposed that should be of interest to plant breeders who are planning to use molecular markers for alfalfa or other tetraploid species.Key words: RAPD markers, tetraploid alfalfa, segregation, linkage groups.

Translocation heterozygosity in southern African species of Viscum

Bothalia ◽  
1980 ◽  
Vol 13 (1/2) ◽  
pp. 161-169 ◽  
Author(s):  
D. Wiens ◽  
B. A. Barlow
Keyword(s):  
Sex Ratios ◽  
Meiotic Drive ◽  
Sex Factors ◽  
Structural Rearrangements ◽  
Dioecious Species ◽  
African Species ◽  
High Frequencies ◽  
Supernumerary Chromosomes ◽  
Adaptive Value ◽  
Translocation Heterozygosity

Sex-associated and floating translocation complexes are characteristic of dioecious species of  Viscum,  but are virtually absent in monoecious species. The majority of dioecious species has fixed sex-associated translocation complexes with the male being the heterozygous sex. The sex-associated multivalent is usually O4 (ring-of-four) or O6 , rarely O8 . Dioecious species without sex-associated translocations are much less common. Most of the dioecious species are also polymorphic for floating translocations, producing one or more additional multivalents ranging from O4 to O12. Floating translocations may be more frequent in species that do not have sex-associated translocations. Supernumerary chromosomes are also present in several species. Sex ratios are at unity in most dioecious species, but female-biased ratios may occur in some species. The high correlation between dioecy and translocation heterozygosity suggests that translocations are primarily associated with the origin and establishment of dioecy. Any róle in the maintenance of biased sex ratios through meiotic drive is probably secondary. Sex-associated translocations may serve to stabilize dioecy by bringing the sex factors into close linkage. Subsequent structural rearrangements within a sex-associated translocation complex may bring the sex factors together in one chromosome pair, releasing floating translocations. The high frequencies of floating translocation heterozygosity in some species indicate that such heterozygosity also has adaptive value.

Inheritance of microsatellite loci in the polyploid lake sturgeon (Acipenser fulvescens)

Genome ◽  
2001 ◽  
Vol 44 (2) ◽  
pp. 185-191 ◽  
Author(s):  
Jonathan D Pyatskowit ◽  
Charles C Krueger ◽  
Harold L Kincaid ◽  
Bernie May
Keyword(s):  
Null Allele ◽  
Female Parent ◽  
Meiotic Drive ◽  
Unreduced Gametes ◽  
Lake Sturgeon ◽  
Acipenser Fulvescens ◽  
Double Reduction ◽  
Disomic Inheritance ◽  
Random Segregation ◽  
Progeny Genotype

Inheritance in the expression of amplicons for four microsatellite primer pairs was determined using 10 families created from gametes of wild lake sturgeon (Acipenser fulvescens). Loci Afu34 and Afu68 expressed a maximum of two even-intensity bands per individual and had progeny genotype ratios that fit disomic inheritance (P > 0.05). Some variation exhibited at Afu34 and Afu68 was attributable to a null allele. Genotype expression at both loci also indicated that one female parent had transmitted unreduced gametes. Primer Afu39 amplified products that exhibited four gene doses, where genotype counts fit expected ratios for disomic inheritance (P > 0.05) indicating amplification of products from two disomic loci that share alleles. Meiotic drive was evident at the Afu39 loci based on a test for random segregation (P < 0.05). Only the expression of Afu19 gave evidence of tetrasomic inheritance based on a single progeny potentially produced by a double reduction gamete. No evidence for proposed octoploid inheritance was observed.Key words: diploid, tetraploid, octoploid, meiotic drive.

scholarly journals Prolactin secretory rhythm of mated rats induced by a single injection of oxytocin

2006 ◽  
Vol 290 (3) ◽  
pp. E566-E572 ◽  
Author(s):  
Marcel Egli ◽  
Richard Bertram ◽  
Natalia Toporikova ◽  
Michael T. Sellix ◽  
Wilfredo Blanco ◽  
...  
Keyword(s):  
Single Injection ◽  
Anterior Lobe ◽  
Time Of Day ◽  
Feedback Mechanism ◽  
Network Function ◽  
Ovx Rats ◽  
Inhibitory Feedback ◽  
Additional Feedback ◽  
Secretory Pattern ◽  
Da Release

Mating or vaginocervical stimulation [copulatory stimulus (CS)] induces two daily surges of the hormone prolactin (PRL) in rats. This unique secretory pattern of PRL surges is characteristic for the first half of pregnancy and is also present in ovariectomized (OVX) rats. Studies have shown that CS additionally provokes an acute release of the hormone oxytocin (OT). In this study, we tested whether a single injection of OT (iv) is sufficient to initiate the PRL secretion pattern of OVX/CS rats. Furthermore, we measured the 24-h profile of dopamine (DA) content in the anterior lobe of the pituitary gland, because DA is the major inhibitory factor of PRL secretion. The results indicated that a single injection of OT induces a PRL secretory rhythm and a DA release pattern similar to that initiated by CS. Immunocytochemical investigation showed that particular OTergic neurons in the hypothalamus express receptors for PRL, as well as for vasoactive intestinal polypeptide, which indicates an involvement in generating the PRL rhythm and entraining it to the ambient photoperiod. On the basis of this study, we suggest that the PRL-DA inhibitory feedback loop between lactotrophs and DAergic neurons plays a crucial role in generating the oscillatory PRL secretion pattern in CS rats. A timing signal, likely provided by the hypothalamic suprachiasmatic nucleus, entrains the autonomous PRL oscillation to a particular time of day. Mathematical modeling was used to illustrate the proposed network function. The experimental results further suggest an additional feedback mechanism in which certain hypothalamic OTergic neurons are influenced by PRL.

scholarly journals FEM Based Study for Estimation of Applanation Force and Influence of Intraocular Pressure on Tonometry

2021 ◽  
Author(s):  
Bharathi Bhat ◽  
Rakshath G. Poojary ◽  
Gopalakrishna Prabhu ◽  
Ramesh S. Ve
Keyword(s):  
Intraocular Pressure ◽  
Internal Structure ◽  
Maximum Stress ◽  
Technology Innovation ◽  
Testing Procedure ◽  
Feedback Mechanism ◽  
Eye Care ◽  
Maximum Deformation ◽  
Biomechanical Simulation ◽  
Additional Feedback

Abstract Purpose: Excess force on cornea during eye care testing procedure such as tonometry may damage the internal structure of eye or may result in erroneous results. The proposed work can be utilized or incorporated as an additional feedback mechanism in the technology innovation of design of eye care instruments. Method: This work is focused on biomechanical simulation of human eye to determine applanation force on cornea and also to find the influence of intraocular pressure (IOP) of eye on Tonometry. Results: The results summarise that force applied by the tonometer will increase linearly for increase in deformation of cornea and the junction of cornea and sclera will undergo maximum deformation and hence will experience maximum stress compared to the centre of cornea where tonometer applanates the cornea. Conclusion: The tonometry will result in deformation of cornea in vertical elongation and the maximum stress is concentrated at the tonometer periphery as well as at the junction of cornea and sclera. The investigation also report that rise in IOP of eye demands higher force of applanation to get the prescribed deformation of cornea.

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