Publication Type: Conference Paper/Unpublished Manuscript
Review Method: Peer Reviewed
Abstract: We'll discuss the notion of clones in matroids. Results relate clones in a matroid to minors of that matroid.
Characterizations of matroids that contain few clonal-classes will be discussed, as well.

Publication Type: Conference Paper/Unpublished Manuscript
Abstract: The controversial nature of cloning continues to fascinate and shock audiences worldwide. To make this technology more palatable to the general public, cloning institutions employ specific rhetorical strategies to offset the negative images associated with this controversial field of science. Recognizing these rhetorical constraints associated with the process of cloning, one institution, Genetic Savings and Clone Inc. (GSC), has carefully crafted its website so its intended audience will accept its message and use the services this company has to offer. GSC, a North American company clones family pets for customers willing to pay a fee of $50,000. GSC manages to subvert controversy with deliberate use of rhetorical strategies that conceals the negative aspects of cloning to the customer. To illuminate these strategies, Bormann’s (1972) Fantasy-Theme Analysis method is employed to analyze the social structures in place allowing GSC to persuade customers to clone their pets. Our analysis concluded that GSC employs a pragmatic rhetorical strategy in which GSC transforms themselves into an expert “doctor with technology as partner” and the customers are rhetorically repositioned as a “patient willing to transplant guilt to the doctor.” Finally, our essay examines future implications for pet owners, and businesses selling controversial products are discussed. This paper is “Questioning the Dialogue” by pinpointing what rhetorical strategy GSC uses that permits audiences to purchase cloning services without concerns or guilt for cloning controversy.

Publication Type: Poster
Abstract: Therapeutic cloning, whereby somatic cell nuclear transfer (SCNT) is used to generate donor-specific embryonic stem cells (ESCs) from cloned blastocysts (ntESCs), holds great promise for the treatment of many human diseases. ntESCs have been derived in mice and cattle, but to date there are no credible reports of human ntESCs. Reproductive cloning in all mammalian species tested has a high failure rate, suggesting that cloned conceptuses are abnormal and raising questions about the feasibility of therapeutic cloning in humans. However, reprogramming of genes expressed in the inner cell mass, from which ES cells are derived, appears to be highly efficient. Our hypothesis of the nuclear reprogramming mechanism involves two steps: 1) de-differentiation of the differentiated donor somatic cell to a totipotent embryonic state; then 2) re-differentiation of cloned embryos to different somatic cell types during later development. The first step of nuclear reprogramming refers to the erasure of the donor cell’s epigenetic pattern following nuclear transfer and the re-establishment of embryonic epigenetic characteristics and gene expression in the cloned embryo. The second step of nuclear reprogramming refers to re-differentiation of cloned embryos from a totipotent status to a differentiated status for tissue/organ formation during post-implantation development. We propose that the low success rate of reproductive cloning is due mainly to inefficiencies in the second step of reprogramming, leading to extraembryonic defects, perhaps as a result of defective reprogramming of epigenetic mechanisms, such as imprinting, that are required for normal placental development. Defects in the extraembryonic lineage are not expected to affect the derivation of ntESCs. Thus, we remain optimistic that human therapeutic cloning is achievable and that patient-specific ESC lines have great potential for regenerative medicine.

Publication Type: Poster
Review Method: Peer Reviewed
Abstract: The ability of embryonic stem (ES) cells to differentiate into germ cells in culture has been established, and functional germ cells, including haploid cells, have been generated. As with many genetic diseases, generation of the missing cell type in vitro for male infertility provides a valuable tool for studying the mechanism of the disease and discovering therapies. Toward this goal, our lab has been applying the somatic cell nuclear transfer (SCNT) technology to develop treatments for genetic disease using the mouse as a model. In the present study, we aimed to correct a mouse germ cell deficiency which renders male infertility. First, we generated cloned embryos using skin fibroblast cells of the infertile mouse, WBB6F1/J-KitW/KitW-v (W/W-v). We then derived nuclear transfer ES cells (ntES) from the cloned embryos. The ntES cell lines carrying this genetic deficiency were characterized for their pluripotency and their genetic deficiency was corrected by gene targeting. Lastly, we determined the potential of the genetically corrected ntES cells for their in vitro ability to differentiate into functional male germ cells and compare that to control ES cell lines. Experiments for in vivo assay of the functions of genetically corrected ntES cells by producing ntES cell-derived animals through tetraploid complementation or second round of SCNT are on-going.
Our research will ultimately lead to not only the production of offspring from infertile mice and advance the study of therapeutic cloning as an alternative assisted reproduction technology (ART) to germ cell therapy in humans, but also offers the unique approach to study cell reprogramming in stem cell - germ cell transformation.

Publication Type: Poster
Abstract: Human ES cell research heavily relies on gene markers to define different cell populations, yet most immunochemical reagents necessary for cell identity are not readily available and will likely take several years to create. It remains a challenge to develop methodologies that would allow the rapid generation of gene markers and also provide an accurate assessment of the respective gene’s expression.
Our lab is currently investigating a Herpes Simplex Virus packaging system to transfer BAC clones into ES cells. It is advantageous to generate reporter gene constructs using BAC clones, which can carry all of the transcriptional regulatory elements of a gene, allowing accurate representation of an endogenous gene's expression. Our goal is to: (1) modify selected genes of interest with fluorescent protein reporters that will mark distinct cell populations, (2) retrofit BACs and package them using and HSV-1 amplicon system, (3) Transduce ES cells to establish transgenic ES cell lines. This methodology will allow investigators to visualize the process of differentiation under live culture conditions and isolate distinct cell populations by FACS.
To test this system, we have successfully packaged a 123KB fragment from the gene, Bone Sialoprotein (BSP), a matrix protein specifically expressed in bone cells. The fluorescent green marker identifies cells in which BSP has been introduced and the fate of these cells can be followed throughout a differentiating cell culture. This amplicon is currently being tested in mouse marrow stromal cells and mouse ES cells.