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1947. The widest gap, still to be filled, between two fields of research in biology, is probably the one between genetics and embryology. It is the repeatedly stated--and thus far unsolved problem--of understanding how cells with identical genomes
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1947 The widest gap, still to be filled, between two fields of research in biology, is probably the one between genetics and embryology. It is the repeatedly stated--and thus far unsolved problem--of understanding how cells with identical genomes may become differentiated, that of acquiring the property of manufacturing molecules with new or, at least, different specific patterns or configurations. Jacques Monod, 1947
Frank Lillie Hans Spemann, Ross Harrison Lillie, Spemann, Harrison, Just “Genetics is a Joke” -no mutants to control early embryogenesis -genes are identical in all cells -environment can influence development Ernest Just
Viable offspring derived from fetal and adult mammalian cells, by I. Wilmut, J. McWhir, A.J. Kind, and K.H.S. Campbell • Goal • To determine whether nuclei undergo irreversible changes during cellular differentiation. • To create viable offspring from: • Adult mammary gland cells • 26 day fetus cells • 9 day embryo cells Technique • Cells removed from donor tissue • Cell forced out of growth phase (into G0) • Nucleus of donor cell injected into recipient oocyte • Cell transplanted into uterus of a receptive ewe
Transplant technique http://web.ukonline.co.uk/webwise/spinneret/genes/clones.htm
Cloning a Mammal: What does this tell us about development and the genome? Nuclei from adult tissues can be totipotent (with appropriate cell-cycle manipulations and the oocyteenvironment). THEREFORE!!!!! The genome of individual adult, differentiated cells contains ALL the genes necessary for ALL cells of the animal.
5.3 Summary of the steps involved in the production of β-globin and hemoglobin (Part 1)
5.3 Summary of the steps involved in the production of β-globin and hemoglobin (Part 2)
5.4 Formation of the active eukaryotic transcription initiation complex (Part 1)
5.4 Formation of the active eukaryotic transcription initiation complex (Part 2)
5.6 The genetic elements regulating tissue-specific transcription can be identified by fusing reporter genes to suspected enhancer regions of the genes expressed in particular cell types
5.8 Three-dimensional model of the homodimeric transcription factor MITF (one protein shown in red, the other in blue) binding to a promoter element in DNA (white)
5.9 Serial sections of the eye in 15.5-day mouse embryos demonstrate that MITF is required for the transcription of pigmention genes