Stem Cells – Cloning – Transgenics Flashcards
What are stem cells?
Unspecialised cells with capacity to self-renew for long periods
What is self-renewal?
Ability of stem cells to divide and maintain an undifferentiated state
What are the three types of embryonic stem cells?
Derived from inner cell mass (ICM) – ES cells (embryonic stem cells)
Derived from the epiblast – EpiSC (epiblast stem cells)
Derived from primordial germ cells – EG cells (embryonic germ cells)
What are the two main classes of tissue stem cells?
Fetal stem cells – cord blood SC, amniotic fluid SC, fetal liver SC
Adult stem cells – neural SC, haematopoietic SC, spermatogonial SC, mesenchymal SC, liver SC, epidermal SC
Define the terms totipotent, pluripotent & multipotent
Totipotent – able to form entire organism (e.g. zygote)
Pluripotent – able to form all the body’s cell lineages, including germ cells (e.g. embryonic stem cells)
Multipotent – can form multiple lineages that constitute an entire tissue or tissues (e.g. haematopoietic stem cells)
What are the uses of stem cells?
Cell-based therapies, drug development and screening, disease models, study of early development, development of new methods for gene therapy
What can mesenchymal stem cells derived from bone marrow or fat be used to treat?
Tendon and ligament injury in horses and dogs & osteoarthritis
What is reprogramming?
The process of reversal of differentiation of somatic cells into pluripotent cells
What is nuclear transfer?
Reconstruction of an embryo by the transfer of genetic material from a donor cell to a recipient egg from which the genetic material has been removed
What is the difference between an identical twin and a clone?
Identical twin – same genetic material, same cell duplicated
Clone – similar genetic material, same cell duplicated
What is the different between reproductive and therapeutic cloning?
Therapeutic – duplicating part of an organism
Reproductive – duplicating an organism
What are the problems with cloning?
Very difficult, problems in health, problems in growth, premature ageing, lack of knowledge
What are the three methods of inducing pluripotency in somatic cells?
Nuclear transfer, fusion & defined factors (e.g. c-myc, Klf4, Oct-4 and Sox2 in mice)
Describe how induced pluripotent stem cells (iPS cells) are obtained across the species
Mouse – induced pluripotent stem cells form mouse embryonic and adult fibroblast cultures by defined factors
Pig – derivation of induced pluripotent stem cells from pig somatic cells
Dog – generation of canine induced pluripotent stem cells by retroviral transduction and chemical inhibitors
Cow – generation of induced pluripotent stem cells from bovine embryonic fibroblast cells
Horse – induced pluripotent stem cell lines derived from equine fibroblasts
What is a transgene?
A gene or segment of DNA containing a specific gene that is transferred by genetic engineering or genetic modification from one organism to another
