In an overwhelming majority of experiments, both mammalian embryonic and somatic cloning have relied on introducing exogenous nuclei into enucleated metaphase II (MII) oocytes. Since attempts at cloning using interphase zygotes as recipient cells have failed, these cells were – until quite recently – commonly regarded as poor recipients for nuclear transfer. However, we have recently shown that...

In angiosperms, fertilization and subsequent zygotic development occur in embryo sacs deeply embedded in the ovaries; therefore, these processes are poorly elucidated. In this study, microarray-based transcriptome analyses were conducted on rice sperm cells, egg cells, and zygotes isolated from flowers to identify candidate genes involved in gametic and/or early zygotic development. Cell type-s...

Nuclear fusion in newly formed Chlamydomonas reinhardtii zygotes can be inhibited by drugs that affect microtubule stability, which include colchicine, amiprophosmethyl, oryzalin, and taxol. This inhibition can be monitored genetically by the production of haploid meiotic products from conjugations between haploid and diploid parents. Such zygotes would normally produce aneuploid progeny. Inhib...

Mouse zygotes do not activate apoptosis in response to DNA damage. We previously reported a unique form of inducible sperm DNA damage termed sperm chromatin fragmentation (SCF). SCF mirrors some aspects of somatic cell apoptosis in that the DNA degradation is mediated by reversible double strand breaks caused by topoisomerase 2B (TOP2B) followed by irreversible DNA degradation by a nuclease(s)....

Currently in vitro culture of mouse preimplantation embryos has become a very important technique to investigate different mechanisms of early embryogenesis. However, there is a big difference in the preimplantation development between mammalian species. Despite close relatedness to mice, in vitro cultivation of rat preimplantation embryos is still delicate and needs further investigation and o...

In Saccharomyces cerevisiae, previous studies on the inheritance of mitochondrial genes controlling antibiotic resistance have shown that some crosses produce a substantial number of uniparental zygotes, which transmit to their diploid progeny mitochondrial alleles from only one parent. In this paper, we show that uniparental zygotes are formed especially when one parent (majority parent) contr...

Cell polarization and asymmetric cell divisions play important roles during development in many multicellular eukaryotes. Fucoid algae have a long history as models for studying early developmental processes, probably because of the ease with which zygotes can be observed and manipulated in the laboratory. This review discusses cell polarization and asymmetric cell divisions in fucoid algal zyg...

Matured bovine oocytes and zygotes obtained by in vitro maturation and fertilization techniques (IVM and IVF) were cytogenetically prepared by using an improved method for chromosome preparations. The method, which involves use of trypsinizedhypotonic solution plus a vortex-agitated system and very cold two-step fixation process, contributes to weaken the zona pellucida and allows the swelling ...

Gene engineering for generating targeted mouse mutants is a key technology for biomedical research. Using TALENs as sequence-specific nucleases to induce targeted double-strand breaks, the mouse genome can be directly modified in zygotes in a single step without the need for embryonic stem cells. By embryo microinjection of TALEN mRNAs and targeting vectors, knockout and knock-in alleles can be...