In mice and humans the X-chromosomal porcupine homolog (Porcn) gene is required for the acylation and secretion of all 19 Wnt ligands and thus represents a bottleneck for all Wnt signaling. We have generated a mouse line carrying a floxed allele for Porcn and used zygotic, oocyte-specific and visceral endoderm-specific ...

BACKGROUND: Chromosomal abnormalities are common in embryos produced in vitro and cause implantation failure, miscarriage, and serious medical problems in infants. Because preimplantation genetic screening (PGS) is increasingly being used to detect aneuploidy in embryos with the purpose of improving implantation rates after IVF (in vitro fertilization), we aimed to ...

PURPOSE: To demonstrate that translocation carrier patients can be identified by analysis of chromosomes in preimplantation human embryos. METHODS: A report of 3 cases in which multiple embryos were found to possess consistent segmental imbalances by CCS. The parents then had a conventional karyotype performed. RESULTS: In each case, parental ...

Despite the clinical importance of aneuploidy, surprisingly little is known concerning its impact during the earliest stages of human development. This study aimed to shed light on the genesis, progression, and survival of different types of chromosome anomaly from the fertilized oocyte through the final stage of preimplantation development (blastocyst). ...

INTRODUCTION: In order to investigate the dynamics of genomic alterations that occur at different developmental stages in vitro, we examined the chromosome content of human preimplantation embryos by molecular-cytogenetic techniques at the single-cell level, up to 13 days post fertilization. METHODS: The embryos were genetically analyzed several times during their development ...

The spindle assembly checkpoint (SAC) functions as a surveillance mechanism to detect chromosome misalignment and to delay anaphase until the errors are corrected. The SAC is thought to control mitosis and meiosis, including meiosis in mammalian eggs. However, it remains unknown if meiosis in the eggs of nonmammalian vertebrate species ...

Morphokinetic analysis of early human embryos in combination with trophectoderm biopsy and chromosomal enumeration by array technology has been shown to identify embryos with single and/or multiple aneuploidies. In a time-lapse imaging study, aneuploid embryos showed a delayed initiation of blastocyst formation and also reached the full blastocyst stage later ...

Failure of interspecific androgenesis between brook charr (Salvelinus fontinalis, Mitchill 1814) and Arctic charr (Salvelinus alpinus, L.) has been attributed to the conflict between the egg cytoplasm of one species and the sperm nucleus of the other species. To overcome this incompatibility, sperm derived from the brook charr×Arctic charr hybrid ...

STUDY QUESTION: What is the incidence of aneuploidy and mosaicism in all cells of top-quality Day-4 embryos analysed by array-based comparative genomic hybridization (array CGH)? SUMMARY ANSWER: Our data show extensive abnormalities in Day-4 embryos. WHAT IS KNOWN ALREADY: Numerous studies on human embryos at Day 3 and Day 5 ...

STUDY QUESTION: How accurate is array comparative genomic hybridization (array CGH) analysis of the first polar body (PB1) and second polar body (PB2) in predicting aneuploidies of maternal meiotic origin in the cleavage stage embryos of women of advanced maternal age? SUMMARY ANSWER: Almost all of the aneuploidies detected in ...

The mitotic spindle is a diamond-shaped molecular apparatus crucial for chromosomal segregation. The regulation of spindle length is well studied but little is known about spindle width. Previous studies suggested that the spindle can self-organize to maintain a constant aspect ratio between its length and width against physical perturbations. Here, ...

In order to produce triploid plants, 2n female gametes were induced by treating female buds and developing embryo sacs of Populus adenopoda Maxim with high temperature exposure. During megasporogenesis, tests were conducted on the relationship between female gametophyte development and morphological changes of female catkins. In the resulting progeny, 12 ...

STUDY QUESTION: Is there an association between chorionic villous vascularization, ultrasound findings and corresponding chromosome results in early miscarriage specimens from a cohort of recurrent pregnancy loss patients? SUMMARY ANSWER: We did not find a significant difference in vascularization scores of chorionic villi between embryonic, yolk sac or empty sac ...

OBJECTIVE: To review clinical outcomes after preimplantation genetic screening. Most methods of embryo viability assessment involve morphologic evaluation at different preimplantation developmental stages. A weak association between blastocyst morphology and aneuploidy has been described, supporting the basis for preimplantation genetic screening (PGS) for assessment of embryo viability. The expected improvement ...

It is well known that extracellular signal-regulated kinase 8 (ERK8) plays pivotal roles in various mitotic events. But its physiological roles in oocyte meiotic maturation remain unclear. In this study, we found that although no specific ERK8 signal was detected in oocyte at the germinal vesicle stage, ERK8 began to ...

OBJECTIVE: The aim of the study is to investigate the meiotic segregation in fresh eggs from anonymous egg donors and to analyze the baseline levels of aneuploidy in this population. RESULTS: The study includes the largest series of donor eggs so far studied: 203 eggs from donors aged between 20 ...

OBJECTIVE: To investigate the meiotic segregation patterns of cleavage-stage embryos from robertsonian translocation carriers and aneuploidy of chromosome 18 according to meiotic segregation patterns. DESIGN: Retrospective study. SETTING: Infertility center and laboratory of reproductive biology and infertility. PATIENT(S): Sixty-two couples with robertsonian translocation carriers. INTERVENTION(S): One blastomere was biopsied from ...

To maintain cell lineage, cells develop a mechanism which can transmit the gene activity information to the daughter cells. In mitosis, TBP (TATA-binding protein), a transcription factor which belongs to TFIID was associated with M phase chromosomes and was proved to be a bookmark for cellular memory. Although previous work ...

Natural hybridization of corals in the Indo-Pacific has been considered rather rare. However, field studies have observed many corals with intermediate interspecific or unusual morphologies. Given that the existence of F1 hybrids with intermediate interspecific morphologies has been proven in the Caribbean, hybrids may also inhabit the Indo-Pacific and occur ...

A previous study comparing the performance of different platforms for DNA microarray found that the oligonucleotide (oligo) microarray platform containing 385K isothermal probes had the best performance when evaluating dosage sensitivity, precision, specificity, sensitivity and copy number variations border definition. Although oligo microarray platform has been used in some research ...

Experiments were conducted to find the differences between post-thaw viability and chromosome aberrations in eight-cell mouse embryos at presence of dimethyl sulfoxide (DMSO) and 1, 2-propanediol (PROH) as croprotectants in different storage durations. In this case-control study, a total number of 720 mouse embryos from about 250 NMRI mice were ...

Interspecific hybrids between cultivars of eggplant (Solanum melongena L.) and its wild relative S. torvum, which has disease resistance and desirable traits for crop improvement, were obtained by cross-hybridization and embryo rescue. Twenty-one hybrid progenies were obtained and examined based on morphological traits, RAPD and ISSR markers. Five of them ...

Casein kinase I alpha (CK1α) is a member of serine/threonine protein kinase, generally present in all eukaryotes. In mammals, CK1α regulates the transition from interphase to metaphase in mitosis. However, little is known about its role in meiosis. Here we examined Ck1α mRNA and protein expression, as well as its ...

OBJECTIVE: To study the chromosome constitution and in vitro development of embryos derived from monopronucleated (1PN) zygotes after intracytoplasmic sperm injection (ICSI). DESIGN: Prospective study. SETTING: Private assisted reproduction center. PATIENT(S): Fifty-four 1PN 2PB zygotes obtained from 48 ICSI cycles. INTERVENTION(S): Pronuclear diameter measured 18 ± 2 hours after ICSI and ...

PURPOSE: Incorporation of a second polar body (PB2) into one of the blastomeres has been considered as a causal mechanism underlying diploid/triploid mixoploidy in humans. Using a mouse model, we examined whether PB2s can participate in the formation of mixoploidy. METHODS: Uptake of BrdU was examined to determine DNA synthesis ...

A hybridization barrier leads to the inability of seed formation after intergeneric crossings between Brassica rapa and Raphanus sativus. Most B. rapa lines cannot set intergeneric hybrid seeds because of embryo breakdown, but a B. rapa line obtained from turnip cultivar 'Shogoin-kabu' is able to produce a large number of ...

Each in vitro produced bovine embryo has only a limited chance of developing into a live calf. As genetically superior embryos can now be identified (Humblot et al. 2010 Vet. Med. Int.), maximizing these odds is desirable. We aim to multiply the elite genetics of selected male embryos by aggregating ...

A critical issue for species integrity is the existence of a telomere elongation program during embryogenesis that ensures sufficient telomere reserves in mammalian newborns. Two different mechanisms have been reported to act on telomere elongation during early embryogenesis: first, the telomerase, the ribonucleoprotein that adds telomeric repeats onto the chromosome ...

Oil content in cottonseed is a major quality trait which when improved through breeding could enhance the competitiveness of cottonseed oil among other vegetable oils. Cottonseed oil content is a quantitative trait controlled by genes in the tetraploid embryo and tetraploid maternal plant genomes, and the knowledge of quantitative trait ...

Offspring of a highly inbred gynogenetic line of Oreochromis aureus displayed 12-fold increase in twinning rate compared to the outbred population. Asymmetric conjoined twins, which consist of a normal embryo attached to a malformed-atrophic twin, were frequently encountered in both gynogenetic (90·7%) and outbred (38·2%) embryos. The monozygotic origin of ...

STUDY QUESTION: When a chromosome aneuploidy is detected in the first polar body and a reciprocal loss or gain of the same chromosome is detected in the second polar body, is the resulting embryo usually aneuploid for that chromosome? SUMMARY ANSWER: When reciprocal aneuploidy occurs in polar bodies, the resulting ...

STUDY QUESTION: What is the optimal stage from oocyte through preimplantation embryo development for biopsy and preimplantation genetic screening (PGS) to detect abnormal chromosome segregation patterns in eggs or embryos from advanced maternal age (AMA) patients? SUMMARY ANSWER: Testing at the polar body (PB) stage was the least accurate mainly ...

Chicken (Gallus gallus domesticus, GGA) and Japanese quail (Coturnix coturnix japonica, CCO) karyotypes are very similar. They have identical chromosome number (2n = 78) and show a high degree of synteny. Centromere positions on the majority of orthologous chromosomes are different in these two species. To explore the nature of this divergence, ...

ABSTRACT: BACKGROUND: Extant sauropsids (reptiles and birds) are divided into two major lineages, the lineage of Testudines (turtles) and Archosauria (crocodilians and birds) and the lineage of Lepidosauria (tuatara, lizards, worm lizards and snakes). Karyotypes of these sauropsidan groups generally consist of macrochromosomes and microchromosomes. In chicken, microchromosomes exhibit a ...

STUDY QUESTION: What are the aneuploidy rates and incidence of mosaicism in good-quality human preimplantation embryos. SUMMARY ANSWER: High-level mosaicism and structural aberrations are not restricted to arrested or poorly developing embryos but are also common in good-quality IVF embryos. WHAT IS KNOWN ALREADY: Humans, compared with other mammals, have ...

Introduction: We aimed to develop and implement a short tandem repeat (STR) polymerase chain reaction alternative to fluorescence in situ hybridisation (FISH) for the preimplantation genetic diagnosis (PGD) of chromosomal translocations. Methods: Selected informative STRs located on translocated arms of relevant chromosomes were used to discriminate between normal and unbalanced ...

In birds as in mammals, sex is determined at fertilization by the inheritance of sex chromosomes. However, sexual differentiation - development of a male or female phenotype - occurs during embryonic development. Sex differentiation requires the induction of sex-specific developmental pathways in the gonads, resulting in the formation of ovaries ...

Meiosis is a highly conserved and stringently regulated process amongst eukaryotic species, but it is also evident that meiotic errors are prevalent in human females. Between 20 and 60% of human eggs are aneuploid (having the wrong chromosome content), whereas less than 4% of human sperm exhibit such deficits. These ...

The factors that sequester transcriptionally repressed heterochromatin at the nuclear periphery are currently unknown. In a genome-wide RNAi screen, we found that depletion of S-adenosylmethionine (SAM) synthetase reduces histone methylation globally and causes derepression and release of heterochromatin from the nuclear periphery in Caenorhabditis elegans embryos. Analysis of histone methyltransferases (HMTs) ...

Chromosome Conformation Capture, or 3C, is a pioneering method for investigating the three-dimensional structure of chromatin. 3C is used to analyze long-range looping interactions between any pair of selected genomic loci. Most 3C studies focus on defined genomic regions of interest that can be up to several hundred Kb in ...

Accumulating evidence demonstrates that the three-dimensional (3D) organization of chromosomes within the eukaryotic nucleus reflects and influences genomic activities, including transcription, DNA replication, recombination and DNA repair. In order to uncover structure-function relationships, it is necessary first to understand the principles underlying the folding and the 3D arrangement of chromosomes. ...

The pioneering work by Professor Soller et al., among others, on the use of genetic markers to analyze quantitative traits has provided opportunities to discover their genetic architecture in livestock by identifying quantitative trait loci (QTL). The recent availability of high-density single nucleotide polymorphism (SNP) panels has advanced such studies ...

Inversion polymorphisms have occupied a privileged place in Drosophila genetic research since their discovery in the 1920s. Indeed, inversions seem to be nearly ubiquitous, and the majority of species that have been thoroughly surveyed have been found to be polymorphic for one or more chromosomal inversions. Despite enduring interest, however, ...

"Convenience cohorts" comprise individuals thought to represent the general population, but chosen because they are readily available for evaluation, rather than at random. As such, these methods are subject to bias and may be misleading. Convenience cohorts have been used to investigate the prognostic significance of chromosomal translocations between the ...

We investigated the performance of two of the most popular differentiation-based methods to detect loci under selection (dfdist/fdist and bayescan) in order to ascertain the average chromosome map distance between the detected outlier markers and the nearest loci under selection. We used a model of neutral markers genetically linked to ...

The analysis of dicentric chromosomes in human peripheral blood lymphocytes (PBLs) by Giemsa staining is the most established method for biological dosimetry. However, this method requires a well-trained person because of the difficulty in detecting aberrations rapidly and accurately. Here, we applied a fluorescence in situ hybridization (FISH) technique, using ...

Wild Triticeae grasses serve as important gene pools for forage and cereal crops. Based on DNA sequences of genome-specific RAPD markers, sequence-tagged site (STS) markers specific for W and Y genomes have been obtained. Coupling with the use of genomic in situ hybridization, these STS markers enabled the identification of ...

BACKGROUND:Several molecular methods, such as quantitative fluorescence PCR and multiplex ligation-dependent probe amplification, currently serve as important adjuncts to traditional karyotyping for the diagnosis of aneuploidy; however, the performance or throughput limitations of these methods hinder their use for routine prenatal diagnosis and population-based postnatal screening. We developed a novel ...

Due to its cost effectiveness, next generation sequencing of pools of individuals (Pool-Seq) is becoming a popular strategy for characterizing variation in population samples. Since Pool-Seq provides genome-wide SNP frequency data, it is possible to use them for demographic inference and/or the identification of selective sweeps. Here, we introduce a ...

Traditionally, hybrid seeds are produced by crossing selected inbred lines. Here we provide a proof of concept for reverse breeding, a new approach that simplifies meiosis such that homozygous parental lines can be generated from a vigorous hybrid individual. We silenced DMC1, which encodes the meiotic recombination protein DISRUPTED MEIOTIC ...