Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sex Preselection”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed1987

The effect of metals and alcohol on sexual isolation in Drosophila melanogaster.

Strong sexual isolation established between D. melanogaster long-term cage populations (originated from common parents and being under selection pressure since 1972) is maintained (with a tendency to increase) for twelve years after the origin of the populations. The sexual isolation is also maintained when the populations are kept in common conditions for about two years, while it dramatically decreases when the populations live on a food medium supplemented with strong chemical selective factors, such as various metals or ethanol. Seasonal or geographical studies of sexual isolation between natural and our cage populations did not reveal significant deviation from random matings. The genetic nature of sexual isolation is discussed.

Animals↗
PubMed1985

[Current status of biotechnology in animal breeding].

On the basis of the embryo transfer new and developing biotechnologies including cryopreservation of embryos, sex predetermination and sex diagnosis (sexing), in vitro fertilization, cloning and production of chimaeras and of transgenic animals are discussed.

Animals↗
PubMed1993

Sexing and detection of gene construct in microinjected bovine blastocysts using the polymerase chain reaction.

We present a polymerase chain reaction (PCR)-based procedure for rapid bovine embryo sexing and classifying embryos for the presence of exogenous DNA. Fourteen bovine blastocysts microinjected with gene construct DNA at the pronuclear stage were divided into quarters and subjected to amplification with construct-specific and sex gene-specific (ZFY/ZFX) primers in the same initial PCR reaction. Blastocysts carrying microinjected construct DNA could be identified by the presence of construct-specific PCR product in approximately 4 h. Approximately half of the microinjected and two of 16 non-microinjected blastocysts typed PCR-positive for the construct DNA. Owing to erroneous amplifications in the two non-microinjected control blastocysts, and the inability of the system to distinguish integrated from non-integrated copies of the microinjected construct, the number of construct-positive blastocysts determined in our assay most likely overestimates the number of true transgenic embryos. Nevertheless, using this assay, we were able to determine that approximately half of the microinjected embryos were negative for the transgene construct and thus could be eliminated from transfer to a recipient cow. Embryo sexing was achieved in less than 6 h by restriction fragment length polymorphism analysis of nested ZFY/ZFX PCR products reamplified from initial PCR reactions. In 11/14 microinjected blastocysts all sections assayed unambiguously as the same sex. In one embryo, only one section was analysed, while two other blastocysts showed some discrepancies of sexing results between the sections analysed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

Preimplantation diagnosis of inherited disease by embryo biopsy: an update of the world figures.

PURPOSE: Cleavage stage embryo biopsy and preimplantation diagnosis was first reported five years ago. The annual collation of the world figures for centres offering this procedure is important to continually assess the efficiency and success of the biopsy, diagnosis and pregnancies obtained. MATERIALS AND METHODS: Data was collected from 14 centres worldwide. The largest series of diagnosis has been performed for those patients carrying X-linked disease where the embryos have been sexed either by PCR or FISH. PCR has also been used for the specific diagnosis of a number of single gene defects, mainly for cystic fibrosis but also for the diagnosis of Lesch Nyhan syndrome, Fragile X, Duchenne muscular dystrophy, Tay Sachs, haemophilia and RhD blood typing. RESULTS: For PCR sexing, a total of 62 cycles have been performed with 14 pregnancies, 8 deliveries and 11 babies born. For FISH sexing, 70 cycles have resulted in 15 pregnancies, 8 deliveries and 11 babies born. For the specific diagnosis of single genes defects, a total of 65 cycles resulted in 21 pregnancies, 12 deliveries and 12 babies born. Overall, 197 cycles were performed, with 171 embryo transfers (86%), 50 pregnancies (25% per cycle, 29% per transfer), 28 deliveries and 34 babies born. CONCLUSIONS: New methods are being developed to increase the scope of preimplantation diagnoses that can be offered. From next year, the biochemical and miscarriage rates will also be recorded.

Abortion, Spontaneous↗
PubMed1996

Fluorescent PCR: a new technique for PGD of sex and single-gene defects.

BACKGROUND: For single-cell diagnosis, particularly preimplantation genetic diagnosis to be successful four main criteria must be achieved: sensitivity, reliability, accuracy, and identification/elimination of contamination. METHODS AND RESULTS: Fluorescent PCR achieves all four necessary criteria and, in addition, currently allows genes on up to nine chromosomes to be simultaneously investigated. Fluorescent PCR has high sensitivity (approximately 1000 x conventional analysis systems), high reliability (97%), and high accuracy (97%) rates for both sex and CF diagnosis in single somatic cells. The low detection threshold allows allelic dropout (one of the main causes of misdiagnosis) to be easily distinguished from PCR phenomena such as preferential amplification. High reliability (90%) and accuracy (97-100%) have been achieved in sex and CF diagnosis in human blastomeres. Fluorescent PCR can also be used to DNA fingerprint (STR profiling) single cells to identify the source/origin of the cell and determine if contamination has occurred. CONCLUSIONS: Fluorescent PCR is therefore a suitable method for PGD.

Alleles↗
PubMed1996

Allele dropout in sequential PCR and FISH analysis of single cells (cell recycling).

PURPOSE: Our purpose was to investigate the feasability of using sequential PCR and FISH analysis of single cells for preimplantation diagnosis. METHODS: Protocols for sequential PCR and FISH analysis of a single fibroblast (cell recycling) were optimized for six loci and the rates of allele specific dropout (ADO) were determined. RESULTS: Conditions that allow reliable genotyping of single cells in lysis buffer were not optimal for amplifying fibroblasts fixed to coverslips. After optimizing conditions, we observed a success rate of 85% for both analyses in sequential PCR-FISH experiments in single cells for the four loci studied. The individual success rates for each technique revealed a slightly higher rate for FISH (91-95%) than for PCR (85-87%) for single cells on coverslips. The presence of two hybridization signals in FISH experiments demonstrated that the failure to amplify both alleles from heterozygous cells on coverslips was due to true ADO, and not the loss of chromosomal material. The ADO rate observed on coverslips varied between 10 and 14%, which is significantly higher than that observed in solution, even after meticulous optimization. CONCLUSIONS: Sequential PCR and FISH analysis of single cells remains an attractive possibility. However, until the problem of the increased rate of ADO is resolved, cell recycling should be applied to clinical preimplantation genetic analysis.

Alleles↗
PubMed1996

Identifying the sex of human preimplantation embryos in X-linked disease: amplification efficiency of a Y-specific alphoid repeat from single blastomeres with two lysis protocols.

INTRODUCTION: Preimplantation diagnosis involves detecting genetic defects in one or two blastomeres biopsied from cleavage stage embryos following a vitro fertilization (IVF). For X-linked recessive disease, identification of the sex of embryos allows transfer of only unaffected females. To examine how critical the preparation of the single blastomere is for amplification of a Y chromosome specific repeat sequence using the polymerase chain reaction (PCR), the incidence of amplification failure has been examined following two lysis protocols. MATERIALS AND METHODS: Amplification of a Y alphoid repeat sequence from single blastomeres disaggregated from cleavage stage embryos was examined after either (1) lysis in distilled water and freeze-thawing twice or (2) a two-step lysis protocol involving an initial treatment in potassium hydroxide and dithiothreitol. Some of the embryos had been previously sexed by cleavage-stage biopsy and fluorescent in situ hybridization with X- and Y-specific probes. RESULTS: Amplification failure occurred in 6 of 50 (12%) and 4 of 60 (7%) single blastomeres from male embryos following lysis in distilled water or using the two-step protocol, respectively. Conversely, amplification from contaminating DNA occurred in 5 of 63 (8%) single blastomeres from female embryos and 6 of 94 (6%) of control medium-blanks. CONCLUSIONS: The incidence of amplification failure was improved but not eliminated using the two-step lysis protocol. At least two cells, therefore, would be necessary for accurate identification of males by amplification of Y-specific repeat sequences alone. Nevertheless, this protocol for preparing cleavage-stage blastomeres is likely to give more consistent amplification of any unique or repeat sequences.

Blastomeres↗
PubMed2002

Sex selection and disability avoidance: is their opposed treatment conceptually consistent?

Sex selection and disability avoidance receive opposed treatment in bioethics literature, legislative practice and public opinion. However, some theorists question this state of affairs by drawing analogies between the harmful consequences of these practices. This paper shares their disapproval of gender selection and disability avoidance, but bases its resistance to these practices on an examination of the concepts of gender and disability. Here it identifies conceptual confusions as another cause of approval of sex selection and disability avoidance. Further, in clarifying the nature of the concepts at issue, and their relationship with the subjects that they apply to, this discussion highlights the existence of relevant analogies between the concepts of gender and disability. Here the social construction and universality of gender and disability allow their differential treatment to be resisted at the conceptual level, creating a strong foundation for more consequentialist arguments against sex selection and disability avoidance.

Abortion, Eugenic↗