(PDF) Introduction to Genetic Analysis 9/e - South Carolina ...physics.scsu.edu/~dscott/gen/slides/slides1.pdfModern genetic analysis has two main components •Classical or Mendelian - DOCUMENTS.TIPS (2023)

  • Genetic

    The scientific analysis of

    legacy variant

  • Genetics: the study of inherited variation

    Gregor Mendel began

    the formal study of


    In 1866 he published

    your results: inherited

    factors are passed

    below unchanged

    of a generation

    to the next (without

    mix or others

    The change)

  • Genetics: the study of inherited variation

    Gregor Mendel developed

    methods still used


    controlled crosses with

    pure breeding lines

    properties tracked for

    several generations

    counted offspring

    developed, tested


  • Includes modern genetic analysis.

    two main components

    Classical or Mendelian genetics Patterns of inheritance, gene transmission

    Studied making controlled crosses

    Genes identified by heritable phenotypic variation

    Molecular genetics and biochemistry Structure, function and regulation of


    Studied by manipulation, analysis of DNA, RNA and proteins

    Genes identified by molecular variation

  • Modern genetics combines

    Mendelian and molecular genetics

    + reverse genetics

  • Organisms are made up of cells. Each cell contains

    Chromosomes Chromosomes carry genes.

    The organization of living beings is based on

    Cells and controlled by genes:

  • Living things have many different

    Structures and chromosomal organizations.

  • DNA is a double helix:

    two threads of


    hold together

    hydrogen bonds

    pairing = adenine - thymine

    Guanine - Cytosine

    A par AT or GC = one

    Basis by

    The length of DNA is

    measured in base pairs

    pb. 1.000 pb = 1 kb

    8 pb

    A closer look at DNA

  • DNA replication: normal semi-conservative replication due to complementary pairing

    Mutation replication error modifies DNA sequence

  • DNA replication is the

    molecular basis for

    chromosome replication

    DNA replication

    two identical daughters


    went to the next


    The only difference

    it is between daughters

    due to rare mutations

  • Mitosis:


    germ line






    germ line



    referred to





    referred to


    DNA replication is at the core of cell reproduction.

  • genetic distance

    estimated by

    (cytochrome c)


  • dna ancestry

    20 generations = 1,048,576 ancestors

  • From genes to phenotype: DNA information is used

    Synthesize enzymes that catalyze

    biological chemical reactions.

    transcript translation



  • Transcription in a eukaryote

    Figure 1-5 Part 2

  • Gene transcription is controlled by a promoter.

    RNA polymerase binding and promoter and

    start transcription

    open transcription promoter

    promoter locked transcription

  • The biochemical mechanism of


  • Transcription in a eukaryote - RNA processing

    introns are removed

    The exons are spliced

  • Transcription and translation in a eukaryote

  • translation

  • amino acid sequence of a

    The protein determines its folding.

    pattern and activity


  • genome genome

    the entire haploid genetic content of an organism

    usually measured in kilobase (kb) pairs or

    Megabasenpaare (mb)

    human haploid genome 3,000,000 kb

    encode the genome

    DNA-encoding protein (< 2% of human protein)


    noncoding genome alles andere

    DNA involved in gene regulation or not

    known function (for example, introns)

  • Genomic structure in different organisms:

    simpler organisms have relatively more coding

    DNA and less non-coding DNA

    13 genes / 20 kb

    11 genes / 20 kb

    0,8 Gen / 20 kb

    0,33 Gen / 20 kb

    Total coding DNA per segment

  • Albinism: a mutated gene

    It does not work


    prevents melanin


    causes albinism

  • Pigmentation is the result of two genes working correctly.

  • An altered gene does not change pigmentation.

  • Two faulty genes lead to albinism

  • DNA can be

    gel analyzed


    View Genetics Links, Gel Electrophoresis Interactive Animation

  • List of DNS

    separated through

    size during


    DNA can be in a gel.

    becomes visible by coloring

  • enzymes are involved

    specific base 6


    at 46 = 4,096

    bp on average

    DNA fragments can be analyzed by electrophoresis.

    obtained by cutting DNA with restriction enzymes

  • A probe can be used to specifically detect

    DNA fragments or chromosomal regions

  • Probes can be used to detect specific macromolecules

    Figure 1-12 Part 2

  • Probes can be used to detect specific macromolecules

    Figure 1-12 Part 3

  • Probes can be used to detect specific macromolecules

    Figure 1-12 Part 4

  • The polymerase chain reaction can be used to obtain specific DNA for analysis.

  • Polymerase chain reaction

    Polymerase Chain Reaction (PCR) - YouTube

    http://www.youtube.com/watch?v=eEcy9k_KsDI&feature=plcp&context=C34ee5e0UDOEgsToPDskJByneyUaFS6PKCRKJqaTQChttp://www.youtube.com/watch?v=eEcy9k_KsDI&feature=plcp&context=C34ee5e0UDOEgsToPDskJByneyUaFS6PKCRKJqaTQhttp://www.youtube.watch= eEcy9k_KsDI&feature=plcp&context= C34ee5e0UDOEgsToPDskJByneyUaFS6PKCRKJqaTQChttp://www.youtube.com/watch?v=eEcy9k_KsDI&feature=plcp&context=C34ee5e0UDOEgsToPDskJByneyUaFS6PKCRKJqaTQC

  • Model organisms in genetics

  • Application of animal models -

    human medicine and

    Developmental Genetics:

    human genes are often similar

    those of other modern animals because humans share a common ancestor with them

  • animal models application

    genetics of human development:

    Extensive knowledge of human genes has been gained from the study of model organisms.

    HOX genes regulate development, control segment identification

  • Examples of medical research:

    Development of drugs against nematode worms

    one third of the ~5,800 worm proteins are

    similar to mammalian proteins

    yeast cancer molecular research

    38% of yeast looks like 2300 proteins

    those of mammals

    fruit flies

    75% of known human disease genes have

    Equivalents in fruit flies

    The p53 gene plays a role in cell death in both

    and uncontrolled growth

  • Genetics: studying inherited variation

    Wild type the common and typical phenotype


    Rare in the population, generally harmful

    Usually discrete phenotype (albinism)

    Polymorphism of more than one wild type

    Natural variation, common in the population

    can be discreet

    Easily identifiable phenotypic categories

    the continuously

    Unclear phenotypic categories

    Types of phenotypic variation

  • Phenotypic variation:

    Wild type vs. mutation

  • Manx cat:

    dominant mutation

  • There's a



    with mutants

    and strange


  • Scientists successfully create Man-Bear-Pig

    Chimera (Bear Pig) published April 1, 2008, Thinkgene.com


    http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http: //www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http:// www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www. thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene. com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/ Los científicos crean con éxito una quimera humana de oso y cerdo/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-cre ate-human-bear-pig-chimera/http://www.thinkgene.com/scientists-successfully-create-human-bear-pig-chimera/

  • Developmental mutants: HOX genes

  • Phenotypic variation:

    Wild-type discrete polymorphism

  • Other discrete polymorphisms in nature

  • Continuous phenotypic variation:

    a common form of polymorphism

  • mutation, discrete

    polymorphism or

    ends of continuum


    Sultan Ksen

    it pings

    Svetlana Pankratova

    8 3

    2 5

  • Sources of phenotypic variation Genetic and non-genetic factors can have an impact

    phenotypic expression

    Only genes with no known environmental impact

    Human examples, eye color, blood type, environment only, no known genetic effects

    Sample of human language and culture Both genetic and environmental impacts

    (genotype X environmental interaction)

    Development of human examples

  • facets of the eye


    Bristles Some fruit fly anatomy

  • Surroundings

    play a role in this

    The expression

    des Wildtypauges


  • eye-shaped mutants

  • an example for


    in between

    genotype and


  • Curly-Wing-Mutation bei Drosophila

    The expression depends on the temperature.

    while development

    250C Cy mutant = curled wings

    180C Cy mutant = normal wings

    sickle cell anemia

    The expression depends on the oxygen tension.

    Sangre, hoz baja en O2


    usually begins in adulthood

    influenced by diet, exercise

    Other examples of genotype X

    environmental interaction

  • Polypterus (pez dragon)

    aquatic and


    land breeding

    altered anatomy and

    facilitate behavior

    terrestrial locomotion

  • Environmental interaction of genotype X

    The expression of the genotype depends at least in part on it.

    on environmental conditions

    Neither the genotype nor the environment alone are

    enough to explain the phenotype - both must be

    known (Like longitude and latitude, both must be known

    Calculate the area of ​​a rectangle)

    Response norm = phenotypic range

    Expression of a genotype on different


  • reaction norm

    for number of bristles:

    colored differently

    represent lines

    various inbreeding



    effect of

    environment varies

    under genotypes

  • The effects of the environment differ between





    has different

    it affects



  • Genotype X Environmental Interactions:

    Implications for selective breeding

    In all populations (plant,

    animal, home, wild)

    many characters: vary continuously

    Several genes contribute to this.

    subject to G X E


  • selective breeding

    There is selective breeding.

    albeit relatively

    are extreme phenotypes

    used for the next


    Selective breeding was important for

    Changes in native plants and animals

    Demonstration of the genetic basis for variation in

    specific properties

    Genotype X Environmental Interactions:

    Implications for selective breeding

  • Phenotypic variation is the basis of

    selective breeding

    Genetic variation is the basis of success

    selective breeding

    selective breeding on

    several generations

    can change the phenotype

    distribution of a


    selective breeding

    Genotype X Environmental Interactions:

    Implications for selective breeding

  • genetic variation

    determines the reaction to it

    selective breeding:

    Traits with higher genetics

    Variations keep evolving

    fast low selective

    to create

    deviation due to

    environmental factors

    do not respond to selection

    Reply to selective

    breeding test

    presence of genetics


  • Selective breeding can produce spectacular results

    Changes over many generations:

    Flight speed of fruit flies in the wind tunnel

  • Heritable traits may respond to selection in

    increasing or decreasing direction

    expression of ownership

  • domestic dogs arose

    with a wild species

    keep something

    significant resemblance

    to the ancestors


  • Selective breeding has

    produce something extreme

    varieties of domestic

    Animals and plants.

  • Voluntary wheelwalking in mice:

    selective breeding can

    genetic component of behavior

  • the maze is running

    Ability in rats: a

    cognitive trait that

    can be changed by


  • Rearing conditions change the phenotypes of

    Selected Maze Bright and Maze Dull lines

    rearing conditions

    Restricted Normal Enriched






    you accept









  • Heritability of Phenotypic Variation

    Heritability is the ratio of phenotypic

    Variation in a population that is responsible

    to the genes

    Only genes without environmental impact

    Trait inheritance is 100% = 1.0

    Environment only without genetic effects

    Trait heritability = 0

    Genetic and environmental effects.

    Heritability > 0 and < 1.0

    Higher heritability = higher probability of a

    the phenotype is faithfully transmitted,

    increased response to selective breeding

  • the heritability is

    often voiced

    as area u

    can differentiate

    widely for

    different properties

  • Summary

    Agricultural plants, animals and laboratory.

    Model organisms react to this selectively.

    To create:

    Response is repeatable, can be extended

    many generations and can lead to a distant phenotype

    outside the normal fluctuation range

    Many complex traits respond to selectivity.

    To create:

    Anatomical, physiological, behavior

    Genetic variation contributes to the variation of

    expression of complex features

    Heritability is a measure of how much

    Variation in a population is due to genes.

  • Human heredity: comparisons of

    identical (MZ) and dizygotic (DZ) twins

    The MZ twins broke up

    Genetically identical, bred differently


    Greater resemblance between members of the

    Pairs = higher heritability

    DZ and MZ twins bred in biological families

    The parenting environment is the same for both

    members of all couples

    Greater similarity between MZ pairs than DZ

    = higher heritability

  • Measurements on separately reared identical twins allow estimates of the heritability of human traits:

    Correlation between members of the twin pair in many pairs provides the heritability of the trait.

  • Number of fingerprints 0.97

    Height 0.85

    CI 0,5 - 0,7

    School performance 0.40

    good memory 0.20

    Heritability of some common traits

  • IQ inheritance is altered by

    Environmental factors: (based on MZ-DZ biological family comparisons)

    median income +

    Healthy diet 0.74

    Poverty (<$10,000/year)

    nutrition, various

    marginal health 0.39

  • Achievement (work hard, strive

    per championship) 0.38

    social closeness (intimacy) 0.15

    Reaction to stress (neuroticism) 0.48

    Aggression 0.67

    Absorption (imagination) 0.74

    Human personality traits show a

    inheritance area

  • Summary

    Genes do not determine the phenotype.

    but set limits to the variation of the reaction norm

    High heritability tighter limits

    Wider boundaries of low heritability

    Individuals can be strong or weak.

    Predisposition to certain phenotypes. The environment plays a role in most features.

    Human Microbiome - Environment

    affects many physiological characteristics

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