Normal Diploids Research Articles

PIWIL1 gene polymorphism and pediatric acute lymphoblastic leukemia relapse susceptibility among Chinese children: a five-center case-control study.

PIWIL1 polymorphisms' role in pediatric acute lymphoblastic leukemia (ALL) relapse susceptibility remains undiscovered. A case-control designed and multiple logistic regression model was performed to evaluate the overall risk of pediatric ALL and five single-nucleotide polymorphisms (SNPs) of PIWIL1 gene (rs35997018 C>T, rs1106042 A>G, rs7957349 C>G, rs10773771 C>T, and rs10848087 A>G) in 785 cases and 1,323 controls, which were genotyped by TaqMan assay. The odds ratio (OR) and its 95% confidence interval (CI) were used to estimate the relationship. Stratified analysis was used to investigate the correlation of rs1106042 and rs10773771 genotypes and pediatric ALL relapse susceptibility in terms of age, sex, number of white blood cells (WBC), immunophenotyping, gene fusion type, karyotype, primitive/naïve lymphocytes, and minimal residual disease (MRD) in bone marrow. Finally, the haplotype analysis was performed to appraise the relationship between inferred haplotypes of PIWIL1 and pediatric ALL risk. Among the five analyzed SNPs, rs1106042 A>G was related to increased ALL risk, and rs10773771 C>T was related to decreased ALL risk. Compared to the GG genotype, the rs1106042 GA/AA had a deleterious effect on children of age <120 months, who were female and male, had high or average number of WBC, pro-B ALL, pre-B ALL, T-ALL, low- and middle-risk ALL, E2A-PBX fusion gene, non-gene fusion, abnormal diploid, high hyperdiploid, hypodiploid, and normal diploid. Moreover, rs1106042 A>G harmfully affected primitive/naïve lymphocytes and MRD on days 15-19, day 33, and week 12. On the contrary, rs10773771 TC/CC exhibited a protective effect on ALL children with the TEL-AML fusion gene. Haplotype analysis demonstrated that haplotypes CAGT, TACC, TACT, and TAGT were significantly associated with increased pediatric ALL relapse susceptibility. PIWIL1 rs1106042 A>G was related to increased ALL risk, and rs10773771 C>T was linked to decreased ALL risk in eastern Chinese children. Rs1106042 GA/AA may predict poor prognosis.

Transcriptome analysis of high mortality phenomena in polyploid fish embryos: An allotriploid embryo case study in hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

Triploidization of diploid fish is an ideal means for achieving polyploid breeding. During the preparation of allotriploid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂), the allotriploid embryos (T) had a much higher morality from the high blastula to middle gastrula stage compared to the normal hybrid diploids (D). Therefore, the internal regulation of gene expression in allotriploid fertilized grouper eggs was explored by comparing the transcriptional profiles of T and D mapped at the high blastula (1), middle gastrula (2), and crystal (3) stages using the Illumina RNA-seq technology. There were 2357 differentially expressed genes (DEGs) found only in T1_vs_T2 and 1585 DEGs found only in T2_vs_T3. According to the GO functional enrichment analysis, when T developed from the high blastula to middle gastrula stage (i.e., pre-embryonic development; T1_vs_T2), the DEGs showed significant enrichment in terms associated with the cell cycle and cytoskeleton, indicating that cell proliferation was inhibited. KEGG pathway analysis of DEGs showed significant enrichment in mRNA processing and translation and in pathways associated with programmed cell death (PCD). Cell differentiation can trigger PCD and the combined effects of up-regulated ripk1, dnm1l, pgam5, Slc25a5, and vdac1 expression and down-regulated fadd expression during pre-embryonic development may have been the main cause of mass mortality in embryos up until the middle gastrula stage. A two-by-two comparison of D2_vs_T2 DEGs at the middle gastrula stage to the aforementioned DEGs expressed only in T revealed that the Parp4 and pole were down-regulated in the pre-development of T, which might lead to decreased DNA repair efficiency. These results could have reflected either (1) the altered physiological state of the cells due to cold-shock treatment or (2) the sensitivity of pre-embryonic development to an elevated number of chromosomes, which induced disrupted gene expression and abnormal cell division. In conclusion, the above study helps explain why allotriploid grouper exhibit high mortality at the middle gastrula stage, improves our understanding of the regulation of triploid embryo development, and provides basic information for reducing mortality at the middle gastrula stage.

Tetraploidy-linked sensitization to CENP-E inhibition in human cells.

Tetraploidy is a hallmark of cancer cells, and tetraploidy-selective cell growth suppression is a potential strategy for targeted cancer therapy. However, how tetraploid cells differ from normal diploids in their sensitivity to anti-proliferative treatments remains largely unknown. In this study, we found that tetraploid cells are significantly more susceptible to inhibitors of a mitotic kinesin (CENP-E) than are diploids. Treatment with a CENP-E inhibitor preferentially diminished the tetraploid cell population in a diploid-tetraploid co-culture at optimum conditions. Live imaging revealed that a tetraploidy-linked increase in unsolvable chromosome misalignment caused substantially longer mitotic delay in tetraploids than in diploids upon moderate CENP-E inhibition. This time gap of mitotic arrest resulted in cohesion fatigue and subsequent cell death, specifically in tetraploids, leading to tetraploidy-selective cell growth suppression. In contrast, the microtubule-stabilizing compound paclitaxel caused tetraploidy-selective suppression through the aggravation of spindle multipolarization. We also found that treatment with a CENP-E inhibitor had superior generality to paclitaxel in its tetraploidy selectivity across a broader spectrum of cell lines. Our results highlight the unique properties of CENP-E inhibitors in tetraploidy-selective suppression and their potential use in the development of tetraploidy-targeting interventions in cancer.

Evaluation of Chromosomal Abnormalities in Acute Myeloid Leukemia (AML) and Acute Lymphoid Leukemia (ALL)

Background: The present study evaluated the chromosomal and molecular variations in patients of acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). Methods and Materials: A cross-sectional study was conducted at the Department of Oncology at a tertiary care center between April 2018 and June 2021. A total of 314 cases of acute myeloid and lymphoid leukemias were evaluated. Molecular and cytogenetic tests were conducted on these patients. Peripheral and bone marrow smears of all the subjects were sent to the laboratory for molecular and cytogenetic studies. The diagnosis was confirmed with morphology and specific staining, such as Gimsa, myeloperoxidase, molecular, and cytogenetic findings. The results of BM karyotype were classified as normal diploid, hypo and hyper diploid, complex karyotype, and pseudo-diploid. Data was explored using Statistical Package for the Social Sciences (SPSS) version 26. Results: A total of 314 patients were included in the study. Around 40 percent were diagnosed with AML while the 60% had ALL. The mean age of patients was 31.5 +/- 5.6 years. The karyotype revealed that 55.4% were normal diploid, 5.2% were hypo-diploid, 8.4% were hyper-diploid, 18.54% were pseudo-diploid, and the remainder had complex karyotype. A significant difference was observed between the acute leukemia and mean age (P &lt; 0.001). The mean age of acute myeloid leukemia (AML) patients was significantly higher than acute lymphoid leukemia (ALL). The pseudodiploid pattern was meaningfully more frequent in the AML patients compared with that in the MDS and ALL patients (P &lt; 0.001). Chromosomal abnormalities including monosomy of chromosome 14 and trisomy of chromosome 3 were the most prevalent. Conclusion: The current study revealed the variations in the chromosomal abnormalities in patients with acute myeloid leukemia (AML) and acute lymphoid leukemia (ALL). The specific patterns associated with particular leukemia can help establish early diagnosis. Keywords: acute myeloid leukemia, acute lymphoid leukemia, chromosome, hematology, malignancy

A Bone Marrow Study; Report of Chromosomal Variations in Hematologic Malignancies Including Acute Myeloid Leukemia, Acute Lymphoid Leukemia, and Myelodisplastic Syndrome (Northeast Iran)

Background: Chromosomal aberrations which occur in different hematologic malignancies are believed to be highly applicable for identifying the prognosis and treatment protocols. We conducted the present study to investigate the chromosomal and molecular abnormalities in bone marrow of acute myeloid leukemia (AML), acute lymphoid leukemia (ALL), and myelodysplastic syndrome patients. Method: We performed this cross-sectional study in molecular pathology and cancer research center of Mashhad University of Medical Sciences (MUMS), during 2017-2019; the total number of our cases was 252. We did all the molecular and cytogenetic tests on these patients. SPSS V.16 software was utilized for the analysis of our data. Results: In this research, the ALL patients were meaningfully younger than AML ones. There were significant associations between karyotype patterns and types of malignancy; normal diploid was more frequent in myelodysplastic syndrome (p <0.05). Among numerical abnormalities, trisomy 3 and monosomy 14 were the most prevalent ones. Conclusion: The results of similar studies from different areas with different ethnics would help to identify new parameters for prognosis determination. Cytogenetic analysis is highly applicable for leukemia diagnosis and prognosis.

High Stability in Chromosomal Traits of &lt;i&gt;Chamaelirium japonicum&lt;/i&gt; and &lt;i&gt;C. koidzuminum&lt;/i&gt; (Melanthiaceae) with Holocentric Chromosomes

Chromosome number, morphology, and behavior in the mitotic cycle were examined for 334 individuals from 34 local populations of Chamaelirium japonicum, including two infraspecific taxa so far chromosomally uninvestigated, and for 20 individuals from three populations of C. koidzumianum, including one variety cytologically unexplored to date. All of the individuals proved to have holocentric chromosomes, and 351 out of the 354 individuals exhibited 2n=24=4L+20S (where L and S denote ‘long’ and ‘short,’ respectively) and were regarded as diploids (2x). Of the other three individuals of C. japonicum ssp. japonicum, two were triploids (3x) with 2n=36=6L+30S, and one was a hyperploid (2x+1) with 2n=25=4L+19S+2f, of which the two small chromosomes (f) presumably arose by fission in one short chromosome. The triploid and the hyperploid showed lower pollen stainability (16.3 and 71.7%, respectively) with cotton blue than normal diploids (98.0–99.5%). Factors leading to the high stability of chromosomal traits in the two species are suggested.

Colchicine Induced Polyploidy in Cassia tora (L.) Rox.

An Induction of artificial polyploidy by 0.4% aqueous solution of Colchicine has been successfully made in Cassia tora . The data obtained from the experimentally treated materials have been further analysed for all the implications to understand the effect of Colchicine on the Chromosome structure, and function. The tetraploids showed n = 26 bivalents and different combinations of univalent and multivalent, the percentage of quadrivalents being the highest Chromosome irregularities in PMCs of polyploids has been detected more frequently than normal diploid. The polyploids thus, raised did show autopolyploidy in nature. The chemical environment within the cell can change the meiotic behaviour of a species. The tetraploid plants showed a slower rate of growth, delayed flowering, thicker, darker and wider leaflet, and decreased stomatal frequency per unit area. This also showed larger stomata, increase in height, increase in number of lateral branching, bigger fruit, seed size and increase in the number of pollen grains with absence of exine. The pollen sterility increases as compared to diploid. It is thus clear that experimental induction by Chemical means (Colchicine) holds a clue for understanding the adaptability of the species in different environmental conditions.

First Report on Aneusomaty and Chromosomal Chimeras in Male Track of Luffa cylindrica (L.) M. Roem

Morpho-cytological studies on existing germplasm of agronomically important taxa provide valuable data for identifying more productive, cytologically normal and stable lines. Presently, one commercial and two local cultivars, viz. MBLC1, MBLC2 and MBLC3 of Luffa cylindrica, were studied for morphological aspects. Of these, two (MBLC1 and MBLC2) bearing larger fruits were more productive. For determining cytological status of these cultivars, chromosome count was made from dividing somatic cells. While MBLC2 and MBLC3 had all the cells with normal diploid count (2n = 26), MBLC1 had deviant counts (23–25 chromosomes) in 8–47% cells in five of the seven root tips scanned, with the cells of the remaining two tips having 26 chromosomes. For determining whether germ line cells also exhibit numerical and structural chromosomal aberrations, meiocytes of three cultivars were scrutinized for chromosome count and behavior. These cultivars usually had 7–11% pollen mother cells (PMCs) with variable number of chromosomes (16–28). Besides, 4–6% meiocytes of MBLC1 and MBLC2 were further notable in having quadri- and hexavalents. These anomalies accounted for irregular anaphasic segregations in 8.3%, 9% and 10.5% cells of MBLC1, MBLC2 and MBLC3, with percentage pollen stainabilities of these being 89, 90 and 94, respectively. Seed set per fruit in the present cultivars, however, valued less (140, 161 and 152) than that on record for normal diploids. In view of current detection of aneusomaty, chromosomal chimerism in male track and reduced seed set in present cultivars, it is proposed that the cultivars commonly grown by farmers should be cytologically evaluated and only those with high yield, normal diploid count, regular chromosome behavior and good seed set should be recommended for cultivation.

Single Nucleotide Polymorphism Array-Based Signature of Genetic Ploidy Groups in Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is characterised by a number of recurrent chromosomal abnormalities which inform prognosis. Low hypodiploidy (HoTr) and high hyperdiploidy (HeH) are genetic subgroups associated with large non-random ploidy shifts, specifically 30-39 chromosomes and 51-65 chromosomes respectively. HoTr ALL often presents with a near triploid karyotype of 60-78 chromosomes through chromosomal endoreduplication without cytokinesis. This presents a diagnostic challenge in distinguishing this poor risk entity from good risk HeH ALL. To date, classification of such challenging cases has been based on the modal chromosome number, the pattern of specific gains, and identification of loss of heterozygosity (LOH) using single nucleotide polymorphism (SNP) arrays where possible. However, loss of cellular context and mixed cell populations (normal diploid, low hypodiploid and near-triploid) when analysing SNP arrays can pose additional analytical difficulty. The aim of this SNP array study was to (1) determine the level of inaccurate genetic subgrouping when cytogenetics only was used to distinguish HeH from doubled up HoTr and (2) develop a diagnostic algorithm to reliably call HeH and HoTr without supporting cytogenetic analysis. SNP arrays were performed on diagnostic ALL samples of 85 patients (46 HoTr, 39 HeH) using Illumina CytoSNP 850k (n=80) or Affymetrix Cytoscan HD (n=5) arrays. Probe level data were uploaded to Nexus Copy Number 10 (BioDiscovery) and manual segments spanning the length of each chromosome were created. No further data pre-processing was carried out and log2 ratio of 0 was automatically assigned to the median log2 ratio of the sample. Chromosomal log2 ratios were normalized within each sample and a variety of machine-learning techniques used to cluster the samples independently of assigned diagnosis. Cases residing in the incorrect cluster based on initial diagnosis were examined in detail using information from cytogenetics and SNP array interpretation. SNP arrays were analysed from 46 HoTr (median age 50.5 years (range 7-87), 43% male) and 39 HeH (median age 7 years (range 1-58), 56% male) patients. Unsupervised clustering of log2 ratios showed a clear distinction between HeH and HoTr patients (figure (A)). Six cases clustered incorrectly based on cytogenetic diagnosis. After detailed interpretation of all cases, including identifying LOH affecting chromosomes 3, 7, 15, 16 and 17, 3/6 cases initially classified as HeH were highly suggestive of HoTr ALL despite having &amp;lt;60 chromosomes. Similarly, 1/6 cases was cytogenetically diagnosed with HoTr but had a SNP array pattern typical of HeH ALL. We identified chromosomes 1, 4, 11, 17, 19, and 21 as those contributing most to the distinction in the HoTr and HeH signatures with the log2 ratio of chromosome 1 the most highly discriminatory in this cohort. Using whole chromosome log2 ratios, HoTr and HeH ALL have distinct profiles. SNP array analysis highlighted at least 4 patients whose ploidy subgroups appeared incorrectly called by cytogenetics, which can affect risk stratification. Crucially, these data call into question the accepted modal chromosome numbers for HeH and HoTr in the near triploid phase and suggest this alone cannot be used to classify patients into these ploidy groups. All samples incorrectly classified as HeH ALL were from adults aged &amp;gt;40 years, suggesting this good risk subgroup is even rarer than previously thought in older adults. After re-classification, our cohort only contained 5/41 adults &amp;gt;40 years with HeH ALL, signifying that HoTr ALL is the commonest genetic ploidy group in older adults with ALL and must still be considered in cases with 50-60 chromosomes. Copy number analysis from SNP arrays is challenging in samples with marked ploidy shift and mixed cell populations. Importantly, a number of our samples had significant contaminating normal DNA and LOH could not be confirmed visually (figure (B)), underlying the need for additional factors to aid classification. Our analysis only takes into account log2 ratio of entire chromosomes, thus permitting a measure of the relative over and under-representation of specific chromosomes within the sample. This method accurately clusters patients even when LOH cannot be clearly visualized from B-allele frequency due to contaminating non-leukemic DNA and supports the development of a diagnostic classifier based on chromosomal log2 ratios. Disclosures Fielding: Amgen: Consultancy; Novartis: Consultancy; Pfizer: Consultancy; Incyte: Consultancy.

Molecular cytogenetic analysis of a hydatidiform mole with coexistent fetus: a case report

BackgroundA hydatidiform mole with a coexisting fetus is a rare condition that commonly occurs as either a partial mole with fetus or a twin pregnancy comprising a complete mole and normal fetus. In the former case, the fetus is triploid, and in the latter case, the fetus is diploid with different alleles from those of the mole. Because there is a difference in the persistent trophoblastic disease incidence between the two, an accurate diagnosis is required.Case presentationWe present a case of a 34-year-old Japanese woman who was pregnant with a hydatidiform mole and two coexisting fetuses. At 17 weeks of gestation, hemorrhage-induced progressive anemia in the mother prompted the decision to terminate the pregnancy, after which no complications occurred. Molecular cytogenetic analysis revealed that one of the fetuses was a normal diploid fetus with the same allele in the fetus and placenta. The hydatidiform mole was revealed to be a mosaic of two diploids, and the other coexisting fetus was a normal diploid that shared one of the mole alleles.ConclusionsThis was presumed to be a rare case of twin pregnancy by triploid embryo formation, followed by loss of an allele due to postzygotic diploidization, development of a diploid fetus, and development of another fetus from a separate embryo. Because of the existence of cases such as this one with a diploid fetus, but without a normal pregnancy coexistent with a complete hydatidiform mole, diagnosis by genetic analysis is required for prognosis.

Modeling the reproductive impact of aquaculture-produced sexually fertile triploids on conspecific diploid populations

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 11:205-211 (2019) - DOI: https://doi.org/10.3354/aei00308 Modeling the reproductive impact of aquaculture-produced sexually fertile triploids on conspecific diploid populations Federico M. Winkler1,2,3,*, Miguel Concha4, Christopher Concha1 1Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Larrondo 1281, Coquimbo 1780000, Chile 2Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Larrondo 1281, Coquimbo 1780000, Chile 3Centro de Innovación Acuícola AquaPacífico, Universidad Católica del Norte, Larrondo 1281, Coquimbo 1780000, Chile 4Departamento de Física, Liceo Bicentenario Alejandro Álvarez Jofre, Victoria 150, Ovalle 1840000, Chile *Corresponding author: fwinkler@ucn.cl ABSTRACT: The use of artificially produced triploid (3n) organisms has been proposed as a strategy to produce total or partial sterility in a number of species in order to prevent the potential negative effects of escapees on the genetic structure and integrity of wild conspecific populations or to avoid having alien species become feral in a new environment. When infertility is incomplete, triploid organisms are able to produce gametes that compete with those produced by wild diploid populations or crops that share the same habitat during reproductive periods, which may adversely affect the reproductive success of the wild population. In the present study, a model was developed in order to estimate the effects of the production of gametes by triploid organisms on the reproductive efficiency of a sympatric diploid population of the same species. The chance of the production of balanced gametes by triploids rapidly reduced with the increase of haploid number of the species. It was concluded that, in most aquatic species, this effect depends on the relative contribution of gametes derived from triploid individuals ( pet), which is determined by the proportion of triploids in the population and their relative fecundity relative to normal diploids. The variation of the reproductive efficiency in a mixed population of diploids and triploids will be directly proportional to pet if only one sex is fertile in triploids but will have a logarithmic relationship if both sexes are fertile. KEY WORDS: Triploids · Risk assessment · Reproductive success · Sterility · Chromosome manipulation · Fecundity Full text in pdf format PreviousNextCite this article as: Winkler FM, Concha M, Concha C (2019) Modeling the reproductive impact of aquaculture-produced sexually fertile triploids on conspecific diploid populations. Aquacult Environ Interact 11:205-211. https://doi.org/10.3354/aei00308 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 11. Online publication date: May 23, 2019 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2019 Inter-Research.

Weighted Correlation Network Analysis (WGCNA) of Japanese Flounder (Paralichthys olivaceus) Embryo Transcriptome Provides Crucial Gene Sets for Understanding Haploid Syndrome and Rescue by Diploidization

Artificial gynogenesis is of great research value in fish genetics and breeding technology. However, existing studies did not explain the mechanism of some interesting phenomena. Severe developmental defects in gynogenetic haploids can lead to death during hatching. After diploidization of chromosomes, gynogenetic diploids may dispense from the remarkable malformation and restore the viability, although the development time is longer and the survival rate is lower compared with normal diploids. The aim of this study was to reveal key mechanism in haploid syndrome of Japanese flounder, a commercially important marine teleost in East Asia. We measured genome-scale gene expression of flounder haploid, gynogenetic diploid and normal diploid embryos using RNA-Seq, constructed a module-centric co-expression network based on weighted correlation network analysis (WGCNA) and analyzed the biological functions of correlated modules. Module gene content analysis revealed that the formation of gynogenetic haploids was closely related to the abnormality of plasma proteins, and the up-regulation of p53 signaling pathway might rescue gynogenetic embryos from haploid syndrome via regulating cell cycle arrest, apoptosis and DNA repair. Moreover, normal diploid has more robust nervous system. This work provides novel insights into molecular mechanisms in haploid syndrome and the rescue process by gynogenetic diploidization.

Mitotic instability in triploid and tetraploid one-year-old eastern oyster, Crassostrea virginica, assessed by cytogenetic and flow cytometry techniques.

For commercial oyster aquaculture, triploidy has significant advantages. To produce triploids, the principal technology uses diploid × tetraploid crosses. The development of tetraploid brood stock for this purpose has been successful, but as more is understood about tetraploids, it seems clear that chromosome instability is a principal feature in oysters. This paper is a continuation of work to investigate chromosome instability in polyploid Crassostrea virginica. We established families between tetraploids-apparently stable (non-mosaic) and unstable (mosaic)-and normal reference diploids, creating triploid groups, as well as tetraploids between mosaic and non-mosaic tetraploids. Chromosome loss was about the same for triploid juveniles produced from either mosaic or non-mosaic tetraploids or from either male or female tetraploids. However, there was a statistically significant difference in chromosome loss in tetraploid juveniles produced from mosaic versus non-mosaic parents, with mosaics producing more unstable progeny. These results confirm that chromosome instability, as manifested in mosaic tetraploids, is of little concern for producing triploids, but it is clearly problematic for tetraploid breeding. Concordance between the results from cytogenetics and flow cytometry was also tested for the first time in oysters, by assessing the ploidy of individuals using both techniques. Results between the two were non-concordant.

The wondrous cycles of polyploidy in plants.

The wondrous cycles of polyploidy in plants.

First report of triploidy in Ailanthus altissima, an invasive tree species

Ailanthus altissima is a woody plant that has become invasively naturalized in many countries. Using nuclear SSR markers, we studied specimens of this species collected throughout Japan and found an individual (labeled Aa-1) that was not diploid. We examined pollen morphology and ploidy level of Aa-1 by optical microscopy and flow cytometry (FCM), respectively. Some pollen grains were morphologically abnormal and much larger than normal. FCM analysis demonstrated that Aa-1 was triploid. Formation of abnormal pollen indicates that Aa-1 may well have reduced fertility compared to normal diploids. If this were the case, vegetative progeny Aa-1 could be used as ornamentals without attendant risks of future naturalization.

Array comparative genomic hybridization analysis of early-stage arrested human embryos

To investigate chromosomal euploidies in early-stage arrested human embryos. To determine the euploidy status of the 24 chromosomes, 13 embryos were analyzed, which included 5 arrested at 4-cell stage, 4 arrested at 8-cell stage, and 4 embryos at blastocyst stage regardless of their morphological scores. All embryos were subjected to biopsy, whole genome amplification, and array comparative genome hybridization analysis. Chromosome euploidies of the arrested embryos can be normal, aberrant and chaotic. Mosaicism is prevalent in early stage cleavage, whilst most of the blastocysts, even with poor morphology, are normal diploid. Arrested embryo may have normal chromosomes euploidy. Mosaicism is common in cleavage stage embryos. Early stage embryo arrest may not be solely attributable to chromosomal aneuploidies and needs further research.

Haploid plants carrying a sodium azide-induced mutation (fdr1) produce fertile pollen grains due to first division restitution (FDR) in maize (Zea mays L.)

We induced a fdr1 mutation in maize which makes haploid plants malefertile due to first division restitution; the optimum sodium azide treatment on maize kernels has been identified. Sodium azide mutagenesis experiments were performed on haploid and diploid maize plants. Kernels with haploid embryos of maize inbred line B55 were induced by pollinating with RWS pollen. These kernels were treated with 0.2, 0.5, or 1.0mM sodium azide solution for 2h. The 0.5mM solution was optimal for inducing numerous albino sectors on the treated plants without significant damage. Kernels of a maize hybrid, Oh43×B55, were treated with sodium azide solutions at concentrations of 1.5, 2.0, 2.5, and 3.0mM. Haploids were generated by pollinating RWS pollen. The highest rate of chlorophyll mutations in seedlings (15.3% [13/85]) was recorded with the 2.5mM concentration. A mutated haploid plant (PP1-50) with higher pollen fertility was isolated during the experiments. This haploid plant produced four kernels on the ear after selfing. These kernels were germinated and produced ears with full seed set after selfing. The haploid plants induced from PP1-50 diploids also exhibited high pollen fertility. In situ hybridization studies showed that meiocytes in PP1-50 haploid anthers underwent first division restitution at a rate of 48% and produced equally divided dyads. We designated the genetic factor responsible for this high pollen fertility as fdr1. PP1-50 haploid ears exhibited high levels of sterility, as seen for regular haploids. Diploid PP1-50 meiocytes in the anther underwent normal meiosis, and all selfed progenies were normal diploids. We concluded that the fdr1 phenotype is only expressed in the anthers of haploid plants and not in the anthers of diploid plants.

Post-ovulatory oocyte aging induces spontaneous occurrence of polyploids and mosaics in artificial fertilization of Japanese eel, Anguilla japonica

Spontaneous polyploids and mosaics have often been observed in artificially propagated larvae of the Japanese eel, Anguilla japonica. However, the mechanisms responsible for such unusual cytotypes are unclear. In this study, we examined the relationship of such polyploidization and mosaicisms in larvae resulting from artificial propagation to egg quality (fertilization rate and hatching rate) and viability of larvae, and then clarified the inducing factors and the mechanism for occurrence of such phenomena. Eggs stripped from females after induced maturation were artificially inseminated with sperm pre-cultured with artificial seminal plasma. Ploidy was determined by measuring the relative DNA content of the nuclei with flow cytometry. Of 968 embryos from 32 full-sib families, 9.1% were determined to be abnormal, most of which were triploids (86.5% of abnormal embryos); others were haploids (1.1%), aneuploids (2.3%), and mosaics (10.1%). The percentage of normal diploids from each family varied between 56.3% and 100% (90.9±11.7%, n=32). A significant positive correlation was found between the fertilization rate (P<0.001) or the hatching rate (P<0.001) and the percentage of diploids. Survival rate of triploid eels was similar to diploid eels at 10days after fertilization whereas aneuploids were inviable. When eggs were left in the body cavity of the female for four hours after ovulation and subsequently fertilized, the percentage of diploids decreased. We tried to elucidate the cause for the occurrence of spontaneous triploids by genetic analysis using 26 microsatellite DNA markers, which have been developed and mapped in relation to the centromere. These results suggest that the occurrence of cytogenetically unusual progeny is associated with over-ripening or aging of ova caused by the lapse of time from ovulation until fertilization, and spontaneous triploid larvae are derived from the duplication of the maternal chromosome set by inhibition of the second polar body release after normal meiosis I (crossing over) in oocyte and fertilization with normal sperm.

Identifying genetic characteristics of different diploids in Japanese flounder based on M-C mapping

To analyze the effects of microsatellite markers located in different positions in linkage group on identifying genetic characteristics of different diploids in Japanese flounder in this study,the mature spawners selected from Japanese flounder selection and breeding flounder were used to produce the normal diploids(ND),meiotic gynogenetic diploids(MGD-1),successive two generation meiotic gynogenetic diploids(MGD-2)and inbred diploid(MGD1H)by crossing mature female from MGD-1 with induced sex reversed male.A set of 72 microsatellite markers distributed evenly in 24 linkage groups were selected from the published genetic linkage maps of Japanese flounder.To estimate microsatellite-centromere map distances,four MGD-1 lines were produced.Under the assumption of complete interference,17 markers were located in the centromeric region,36 in the distant region from the centromere and 19 in the intermediate region of linkage groups.The genetic characteristics of four types of diploid in Japanese flounder were identified by these markers.Analysis showed that the number of allele(A)and polymorphism information content(PIC)have limited variation range,in which the A and PIC of ND were the highest while those of MGD1H were the lowest.In four types of diploid,the observed heterozygosity decreased and homozygosity increased as microsatellite-centromere map distance increased.The highest and lowest percentages of homozygous individuals were found in centromeric region from 8.8% to 29.1% and in telomeric region from 2.4% to 23.2%,respectively.The variation ranges of MGD-1and MGD-2 were significantly higher than that of the other diploids.The results demonstrated that choice of microsatellite markers located in different positions in linkage group has great impact on identifying genetic characteristics of different diploids in Japanese flounder.

Haematology of gynogenetic diploids of Siberian sturgeon Acipenser baerii Brandt

Haematological analyses were conducted in gynogenetic diploids and control diploids of Siberian sturgeon (Acipenser baerii). Gynogenetic diploid fish were obtained from Polish aquaculture after induction of meiotic gynogenesis based on application of UV-irradiated hybrid Siberian sturgeon × Russian sturgeon (A. gueldenstaedtii) sperm (for eggs activation) and heat shock for inhibiting the second polar body retention. A total of fifteen 30-month-old specimens of Siberian sturgeon from the gynogenetic diploid group and 12 specimens from the control diploid group were randomly sampled. There were no differences in the number of erythrocytes and haematocrit values between gynogenetic diploids and normal diploids of Siberian sturgeon. However, the percentage of normal erythrocytes was lower in the gynogenetic group of fish and the higher percentage of the atypical red blood cell forms (microcytes, sphaerocytes, erythrocytes with displaced nuclei and with divided nuclei) were observed in this group of fish. Additionally all the haemoglobin indices (haemoglobin concentration, the mean corpuscular haemoglobin and the mean corpuscular haemoglobin concentration) were significantly reduced in gynogenetic diploids of Siberian sturgeon. These results could suggest depletion of oxygenation capacity of the blood of gynogenetic sturgeons. This is the first report of a haematological study in gynogenetic diploids of sturgeon fish.