A genetic chimerism or chimera is a single organism composed of cells with more than one distinct genotype. In animals and human chimeras, this means an individual derived from two or more zygotes, which can include possessing blood cells of different blood types, and subtle variations in form (phenotype). Animal chimeras are produced by the merger of two embryos. In plant chimeras, however, the distinct types of tissue may originate from the same zygote, and the difference is often due to mutation during ordinary cell division. Normally, genetic chimerism is not visible on casual inspection; however, it has been detected in the course of proving parentage. In contrast, an individual where each cell contains genetic material from two organisms of different breeds, varieties, species or genera is called a hybrid.
Gastrulation is the stage in the early embryonic development of most animals, during which the blastula, or in mammals the blastocyst, is reorganized into a two-layered or three-layered embryo known as the gastrula. Before gastrulation, the embryo is a continuous epithelial sheet of cells; by the end of gastrulation, the embryo has begun differentiation to establish distinct cell lineages, set up the basic axes of the body, and internalized one or more cell types including the prospective gut.
In biology and genetics, the germline is the population of a multicellular organism's cells that develop into germ cells. In other words, they are the cells that form gametes, which can come together to form a zygote. They differentiate in the gonads from primordial germ cells into gametogonia, which develop into gametocytes, which develop into the final gametes. This process is known as gametogenesis.
Sir Martin John EvansFLSW is an English biologist who, with Matthew Kaufman, was the first to culture mice embryonic stem cells and cultivate them in a laboratory in 1981. He is also known, along with Mario Capecchi and Oliver Smithies, for his work in the development of the knockout mouse and the related technology of gene targeting, a method of using embryonic stem cells to create specific gene modifications in mice. In 2007, the three shared the Nobel Prize in Physiology or Medicine in recognition of their discovery and contribution to the efforts to develop new treatments for illnesses in humans.
Dame Anne Laura Dorinthea McLaren, was a British scientist who was a leading figure in developmental biology. She paved the way for women in science and her work helped lead to human in vitro fertilisation (IVF). She left an enduring legacy marked by her research and ethical contributions to the field. She received many honors for her contributions to science, including election as fellow of the Royal Society.
The inner cell mass (ICM) or embryoblast is a structure in the early development of an embryo. It is the mass of cells inside the blastocyst that will eventually give rise to the definitive structures of the fetus. The inner cell mass forms in the earliest stages of embryonic development, before implantation into the endometrium of the uterus. The ICM is entirely surrounded by the single layer of trophoblast cells of the trophectoderm.
Lefty are a class of proteins that are closely related members of the TGF-beta superfamily of growth factors. These proteins are secreted and play a role in left-right asymmetry determination of organ systems during development. Mutations of the genes encoding these proteins have been associated with left-right axis malformations, particularly in the heart and lungs.
In developmental biology, the cells that give rise to the gametes are often set aside during embryonic cleavage. During development, these cells will differentiate into primordial germ cells, migrate to the location of the gonad, and form the germline of the animal.
Cripto is an EGF-CFC or epidermal growth factor-CFC, which is encoded by the Cryptic family 1 gene. Cryptic family protein 1B is a protein that in humans is encoded by the CFC1B gene. Cryptic family protein 1B acts as a receptor for the TGF beta signaling pathway. It has been associated with the translation of an extracellular protein for this pathway. The extracellular protein which Cripto encodes plays a crucial role in the development of left and right division of symmetry.
Nodal homolog is a secretory protein that in humans is encoded by the NODAL gene which is located on chromosome 10q22.1. It belongs to the transforming growth factor beta superfamily. Like many other members of this superfamily it is involved in cell differentiation in early embryogenesis, playing a key role in signal transfer from the primitive node, in the anterior primitive streak, to lateral plate mesoderm (LPM).
Gail Roberta Martin is an American biologist. She is professor emerita in the Department of Anatomy, University of California, San Francisco. She is known for her pioneering work on the isolation of pluripotent stem cells from normal embryos, for which she coined the term 'embryonic stem cells'. She is widely recognized for her work on the function of fibroblast growth factors and their negative regulators in vertebrate organogenesis. She and her colleagues made contributions to gene targeting technology.
Janet Rossant, is a developmental biologist well known for her contributions to the understanding of the role of genes in embryo development. She is a world renowned leader in developmental biology. Her current research interests focus on stem cells, molecular genetics, and developmental biology. Specifically, she uses cellular and genetic manipulation techniques to study how genes control both normal and abnormal development of early mouse embryos. Rossant has discovered information on embryo development, how multiple types of stem cells are established, and the mechanisms by which genes control development. In 1998, her work helped lead to the discovery of the trophoblast stem cell, which has assisted in showing how congenital anomalies in the heart, blood vessels, and placenta can occur.
The Nodal signaling pathway is a signal transduction pathway important in regional and cellular differentiation during embryonic development.
Allan Bradley FRS is a British geneticist at the Wellcome Trust Sanger Institute.
Rosa Susan Penelope Beddington FRS was a British biologist whose career had a major impact on developmental biology.
Margaret Buckingham, is a British developmental biologist working in the fields of myogenesis and cardiogenesis. She is an honorary professor at the Pasteur Institute in Paris and emeritus director in the Centre national de la recherche scientifique (CNRS). She is a member of the European Molecular Biology Organization, the Academia Europaea and the French Academy of Sciences.
Magdalena Żernicka-Goetz is a Polish-British developmental biologist. She is Professor of Mammalian Development and Stem Cell Biology in the Department of Physiology, Development and Neuroscience and Fellow of Sidney Sussex College, Cambridge. She also serves as Bren Professor of Biology and Biological Engineering at California Institute of Technology (Caltech).
Left-right asymmetry is the process in early embryonic development that breaks the normal symmetry in the bilateral embryo. In vertebrates, left-right asymmetry is established early in development at a structure called the left-right organizer and leads to activation of different signalling pathways on the left and right of the embryo. This in turn cause several organs in adults to develop LR asymmetry, such as the tilt of the heart, the different number lung lobes on each side of the body and the position of the stomach and spleen on the right side of the body. If this process does not occur correctly in humans it can result in the syndromes heterotaxy or situs inversus.
Peter Anthony Koopman is an Australian biologist best known for his role in the discovery and study of the mammalian Y-chromosomal sex-determining gene, Sry.
Marisa Bartolomei is an American cell biologist, the Perelman Professor of Cell and Developmental Biology and Co-Director of the Epigenetics Institute at the Perelman School of Medicine at the University of Pennsylvania. Her research considers epigenetic processes including genomic imprinting. She was elected to the National Academy of Sciences in 2021.
