A couple requested preimplantation genetic analysis for a dominant form of retinitis pigmentosum caused by a C-->A transversion in the rhodopsin gene. Since this point mutation does not alter a restriction endonuclease site we designed two separate analytical systems, one involving site-specific mutagenesis and the other involving allele-dependent length polymorphism. After establishing the acc...

We have used two different experimental approaches to demonstrate topological separation of parental genomes in preimplantation mouse embryos: mouse eggs fertilized with 5-bromodeoxyuridine (BrdU)-labeled sperm followed by detection of BrdU in early diploid embryos, and differential heterochromatin staining in mouse interspecific hybrid embryos. Separation of chromatin according to parental ori...

The robust independence of preimplantation embryo development in vitro suggests that the developmental programme is autonomous. The rapid accumulation of evidence during the last decade for participation of many hormones, growth factors and their receptors in these early stages of embryogenesis has challenged this conclusion. In this review, the insulin and epidermal growth factor families, whi...

The aim of prenatal genetic diagnosis is to give parents the option of terminating affected pregnancies. For most X linked conditions specific diagnosis is not possible and the only option is induced abortion of all male fetuses, of which half would be unaffected. An altemative is offered by preimplantation diagnosis of sex in embryos obtained by in vitro fertilisation and selective transfer of...

Recently, assisted reproductive techniques have been used to prevent further miscarriages in women with recurrent miscarriage. One approach uses either screening or diagnosis of embryonic chromosomes prior to embryo replacement [preimplantation genetic screening (PGS)/preimplantation genetic diagnosis (PGD)]. The second approach involves surrogacy. However, PGS/PGD assumes that the embryo is ch...

Strain PO preimplantation embryos were labelled with [H]thymidine. The incorporation of the label was studied by autoradiography of air-dried and serially sectioned embryos. DNA amounts were measured with a microdensitometer. The following observations were made at the 5to 16-cell stages. All nuclei contained 2C-4C amounts of DNA and all could eventually synthesize DNA. However, after short lab...

During mouse preimplantation embryo development, totipotent blastomeres generate the first three cell lineages of the embryo: trophectoderm, epiblast and primitive endoderm. In recent years, studies have shown that this process appears to be regulated by differences in cell-cell interactions, gene expression and the microenvironment of individual cells, rather than the active partitioning of ma...

Progression of fertilized mammalian oocytes through cleavage, blastocyst formation and implantation depends on successful implementation of the developmental program, which becomes established during oogenesis. The identification of ooplasmic factors, which are responsible for successful embryo development, is thus crucial in designing possible molecular therapies for infertility intervention. ...

Preimplantation mouse embryos express both classical (class Ia) and nonclassical (class Ib) MHC class I proteins, and yet are not rejected by the maternal immune system. Although the function of the embryonic MHC class Ia proteins is unknown, one MHC class Ib protein, Qa-2, the product of the preimplantation embryo development (Ped) gene, actually enhances reproductive success. Similar in struc...

The embryo culture technique has been improving, but the detailed demands for energy substrates such as glucose, fructose, pyruvate and lactate of preimplantation embryos are still unclear. In the present study, the demands of pig preimplantation embryos at each different developmental stage were investigated by use of parthenogenetic diploids as a model of pig preimplantation embryos. Pig part...