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    Lecture 7. Developmental Genetics

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    Jimmy Beast
    This lecture discusses developmental genetics and the mechanisms of differential gene expression. It defines developmental genetics as the study of gene regulation and cell differentiation during development, from a fertilized egg to an adult organism. Differential gene expression is the basis of cell differentiation, where different cell types are formed through selective activation of genes in response to changing cytoplasmic environments. Gene expression is controlled at various levels, including pre-transcriptionally through gene amplification and chromatin remodeling, transcriptionally via initiation and splicing, translationally by selective mRNA translation, and post-translationally through modifications of the final protein. Together, these regulatory mechanisms allow cells with identical genomes to take on specialized roles.

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    Lecture 7. Developmental Genetics

    Uploaded by

    Jimmy Beast
    10 views25 pages
    This lecture discusses developmental genetics and the mechanisms of differential gene expression. It defines developmental genetics as the study of gene regulation and cell differentiation during development, from a fertilized egg to an adult organism. Differential gene expression is the basis of cell differentiation, where different cell types are formed through selective activation of genes in response to changing cytoplasmic environments. Gene expression is controlled at various levels, including pre-transcriptionally through gene amplification and chromatin remodeling, transcriptionally via initiation and splicing, translationally by selective mRNA translation, and post-translationally through modifications of the final protein. Together, these regulatory mechanisms allow cells with identical genomes to take on specialized roles.

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    This lecture discusses developmental genetics and the mechanisms of differential gene expression. It defines developmental genetics as the study of gene regulation and cell differentiation during development, from a fertilized egg to an adult organism. Differential gene expression is the basis of cell differentiation, where different cell types are formed through selective activation of genes in response to changing cytoplasmic environments. Gene expression is controlled at various levels, including pre-transcriptionally through gene amplification and chromatin remodeling, transcriptionally via initiation and splicing, translationally by selective mRNA translation, and post-translationally through modifications of the final protein. Together, these regulatory mechanisms allow cells with identical genomes to take on specialized roles.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    10 views25 pages

    Lecture 7. Developmental Genetics

    Uploaded by

    Jimmy Beast
    This lecture discusses developmental genetics and the mechanisms of differential gene expression. It defines developmental genetics as the study of gene regulation and cell differentiation during development, from a fertilized egg to an adult organism. Differential gene expression is the basis of cell differentiation, where different cell types are formed through selective activation of genes in response to changing cytoplasmic environments. Gene expression is controlled at various levels, including pre-transcriptionally through gene amplification and chromatin remodeling, transcriptionally via initiation and splicing, translationally by selective mRNA translation, and post-translationally through modifications of the final protein. Together, these regulatory mechanisms allow cells with identical genomes to take on specialized roles.

    Copyright:

    © All Rights Reserved
    Download as PDF, TXT or read online from Scribd
    Download as pdf or txt
    of 25

    Lecture 7.

    Developmental
    Genetics
    Darius Noel C. Minoza
    Department of Biological Sciences
    College of Arts and Sciences
    Visayas State University
    Lecture Objectives
    At the end of this lecture, the students will be
    able to:
    1. Discuss differential gene action
    2. Describe mechanisms of gene action in both
    prokaryotes and eukaryotes
    3. Explain the control of genes in development
    What is Developmental
    Genetics?
    Studies the relationships between gene
    regulation and cell differentiation during
    development
    During development, a fertilized egg becomes
    an adult organism
    Development is a process of regulated growth
    Results from interaction of the genome with the
    cytoplasm and environment
    What is Developmental
    Genetics?
    Development
    ✔requires several gene actions, because the phenotype
    is the expression of the genotype
    ✔ involves programmed sequence of phenotypic events
    which are typically irreversible
    ✔ requires formation of different cell types
    ✔ all cells have identical genotypes
    ✔ regulatory events lead to different cellular
    phenotypes
    A. Differential Gene Action:
    The Basis of Cell
    Differentiation
    After fertilization,
    ✔ zygote undergoes embryogenesis
    ✔ active cell division happens
    ✔ different cell types are formed
    ❑ determination – cell makes an irreversible
    commitment to a specific developmental path
    ❑ differentiation – expression of the cell’s specialized
    role
    Initial cytoplasmic
    environment in the
    embryo is provided
    by the maternal
    genome.

    Cytoplasmic
    determinants trigger
    the switching on of
    genes.
    - Sequence of complex changing
    populations of cells
    Consider these points
    Properties of a differentiated cell reflects
    the activity of genes
    Cells exactly the same genotype
    A cell manifests only a fraction of its genes
    Genes and chromosomes are equally distributed
    Chemical environments of the genes differ
    Different chemical/physiological environments
    induce different sets of genes to be expressed
    Hence, differential regulation of gene function
    Consider these points
    Distinctions of differentiated cells could
    be due to, largely, different compositions
    of enzymes
    Because enzyme structure is coded for by
    the DNA, appearance of a protein = gene
    for such protein is active
    Qualitative differences in protein content
    in the cells = differences in the schedule of
    functioning genes
    Consider these points
    The final phenotype in the cell is the result
    of selective gene expression at several
    steps in cell metabolism
    ✔ Pre-transcriptional control
    ✔ Transcriptional control
    ✔ Translational control
    ✔ Post translational modification
    1. Pre-transcriptional control
    Gene amplification
    ✔ observed in oocytes
    of some species and
    in certain embryonic
    cells
    1. Pre-transcriptional control

    Condensation
    and
    decondensation
    of the chromatin
    2. Transcriptional control

    Differential
    initiation
    2. Transcriptional control

    Differential
    splicing
    2. Transcriptional control

    Differential
    splicing
    2. Transcriptional control

    Differential
    splicing
    2. Transcriptional control

    Selective pre-mRNA
    degradation
    3. Translational control

    Selective translation
    3. Translational control

    Stability of mRNA
    4. Post translational
    modification

    Deletion of a part of
    the peptide chain
    4. Post translational
    modification
    Changes in the Malate
    dehydrogenase
    state of oxidation
    or reduction
    affecting enzyme
    structure

    Lactate
    dehydrogenase
    4. Post translational
    modification
    Sialic acid
    Attachment
    of a small
    molecular
    moiety of the
    enzyme
    Alkaline
    phosphatase
    4. Post translational
    modification
    Polymerization
    and
    combination
    with phosphate
    groups
    Glycogen
    phosphatase

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