Biology Seventh Edition Solomon Berg Martin Chapter 16
Biology, Seventh Edition Solomon • Berg • Martin Chapter 16 Genes and Development Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Development of an organism – Organisms contain many types of cells specialized both structurally and metabolically – All descend from a single zygote – Development is all changes that occur in life • Cell determination – Groups of cells become committed – Leads to cell differentiation – Differences among cell types due to differential gene expression Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Nuclear equivalence • Nuclei of all differentiated cells are genetically identical • Different cells express different subsets of genes – Somatic cells – Germ line cells • Totipotency – Capability of cells to direct development of entire organism Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Vertebrate cell lineages Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Cell totipotency Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Nuclear totipotency Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Mouse models to study disease • Ethically researchers often cannot use humans as test subjects • Animal model is used instead – An example is cystic fibrosis, a genetic disease – Gene targeting is used to produce mice homozygous or heterozygous for cystic fibrosis Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • First cloned mammal • 1997 • Cloned sheep “Dolly” was born in Scotland • Genetic material derived from – Cultured adult sheep’s mammary gland cell – Fused with enucleated sheep’s egg – Cultured in vitro and transferred to host mother Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Mammalian cloning Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Stem cells • Undifferentiated cells • Can produce differentiated descendants • Also retain ability to reproduce themselves • Totipotent stem cells – Give rise to all cell types • Pluripotent stem cells – More specialized Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Exceptions to nuclear equivalence • Genomic rearrangements – Physical changes in gene structure • Gene amplification – More copies of certain genes for transcription Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Gene amplification Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Choice of organisms for research in developmental genetics • Fruit fly, Drosophila melanogaster – Abundance of mutant alleles and ease of mapping new mutations on the chromosomes • Roundworm, Caenorhabditis elegans – Lineage of every somatic cell is known • Laboratory mouse, Mus musculus – Used in studies of mammalian development Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Life cycle of Drosophila Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Location of imaginal discs in Drosophila Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Maternal effect genes • Genes that organize structure of egg cells • Genes in maternal tissues transcribed to produce m. RNA molecules that are transported in egg • Analysis of mutant Drosophila revealed that these genes involved in polarity of embryo Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Early development in Drosophila Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Classes of genes involved in pattern formation of embryonic segments in Drosophila Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Segmentation genes • Genes that generate a repeating pattern of body segments within embryo – Gap genes – Pair-rule genes – Segment polarity genes – Homeotic genes Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Comparison of mutations in Drosophila segmented genes Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Antennapedia Locus Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Hox gene clusters Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Induction and apoptosis • Induction in C. elegans – Developmental interactions with neighboring cells – Anchor cell induces surface cells to form vulva • Apoptosis in humans – During development, hand forms a webbed structure – Fingers become individualized when cells between them die Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Caenorhabditis elegans Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Cell lineages of C. elegans Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Induction in C. elegans Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Mouse model for mammalian development • Transgenic mice studied • Early development of mice and other mammals similar • Almost all research in stages leading to implantation • Chimera – Organism containing two or more kinds of genetically dissimilar cells from two zygotes Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Chimeric mice Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Producing a transgenic mouse Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development • Cancer and cell development • Cancer-causing oncogenes – Proto-oncogenes – Code for various growth factors or growth factor receptors – Respond to stimulation by growth factors – Cell may misinterpret signal and grow and divide inappropriately • Tumor suppressor gene mutation Copyright © 2005 Brooks/Cole — Thomson Learning
Biology, Seventh Edition CHAPTER 16 Genes and Development Cell growth control cascade Copyright © 2005 Brooks/Cole — Thomson Learning
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