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CHAPTER 14 AND 15 - Coggle Diagram

- - - - linked genes
        
        located on the same chromosome tend to be inherited together
    - - Y-linked are related to sex determination
      - for arecessuve X-linked trait to be expressed, a female needs two copies of the allele and male only one copy of the allele :
  - - - offspring with a phenotype matching one of the parental phenotypes
    - - offspring with nonparenral phenotypes
      - recombination chromosomes bring alleles together in new combinations gametes
    - - am ordered list of the genetic loci along a particular chromosome
      - linkage map
        
        genetic map of chromosome based on recombination frequencies
      - map units
        
        distance s between genes
  - - - pairs of homologous chromosomes do not separate normally during meiosis
      - aneuploidy
        
        results from fertilization of gaametes inwhich nondisjunction occurred
        
        example offspring with this have abnormal number of a particular chromosome
        
        klinefelter syndrome
        
        result of an extra chromosome in a male producing XXY
      - monosomic zygote
        
        has only one copy of a particular chromosome
      - trisomic zygote
        
        has three copies of a particular chromosome
      - polyploidy
        
        a condition in which an organism has more complete sets of chromosome
        
        triploid (3n)
        
        three sets of chromosomes
        
        tetraploidy (4n)
        
        four sets of chromosomes
        
        common in plants
    - - deletion
        
        removes a chromosomal fragment
      - duplication
        
        repeats segment
      - inversion
        
        reverse orientation of segment within a chromosome
      - translocation
        
        moves segment from one chromosome to another
  - - - results from three copies of chromosome 21
      - increases with the age of a mother
    - - results from a specific deletion in chromosome 5
      - example a child born with this is severely disabled intellectually and has a cat like cry
- - - - a heritable feature that varies among individuals
        
        example a flower color
    - - each variant for character
        
        example white color for flowers
    - - short generation
      - large numbers of offsprings
      - controlled mating
    - - plants that produce offsprings of the same variety when they self-pollinate
      - hybridization
        
        two contrasting true breeding varieties
      - P generation
        
        true breeding parents
      - F1 generation
        
        the hybrid offspring of the P generation
      - F2 generation
        
        when F1 self-pollinate or cross pollinate with other F1
    - - the allele pairs separate during gamete formation and each gamete randomly receives only one allele per gene
      - Mendel reasoned that only the purple flower factor was affecting flower color in the F1 hybrids
        
        he called the purple flower color dominant trait
        
        determines an organism's appearance
        
        white color a recessive trait
        
        has no noticeable effect
        
        allele
        
        different versions of a gene
        
        homozygote
        
        two identical alleles for a gene
        
        heterozygote
        
        two different allels for a gene
        
        are not true breeding
    - - physical appearance, internal anatomy, physiology, and behavior
      - reflects its overall genotype and unique environmental history
    - - genetic makeup
        
        in the example of flower color in pea plants, PP and Pp plants have same phenotype but different genotypes
    - - how to determine the genotypeof organisms
        
        example breeding the mystery individual with a homozygous recessive individual
    - - monohybrid
        
        meaning that threy were neterozygous for one character
        
        multiplication rule
        
        states that the probability that two or more independent events will occur together is the product of the probability that of their individual probabilities
        
        addition rule
        
        that the probability that any one of the two or more mutually exclusive events will occur is calculated by adding together their individual probabilities
      - dihybrid
        
        crossing two true-breeding parents differing in two characters produces dihybrids in the F1 generation
      - it states that each pair of alleles segregates independently of any other pair during gamete formation
        
        it only applies to genes on different nonhomologous chromosomes
    - - complete dominance
        
        occurs when phenotypes of the heterozygote and dominant homozygote are identical
      - incomplete dominance
        
        neither alleles is completely dominant resulting in heterozygous ofspring with a blended or intermediate phenotype
      - codominance
        
        two dominant alleles affect the phenotype in a separate, distinguishable ways
      - dominant alleles are not necessarily more common in populations than recessive alleles
      - pleiotropy
        
        most genes have multiple phenotypic effects
        
        example they are responsible for multiple symptoms of certain hereditary diseases like sickle cell disease
      - epistasis
        
        one gene affects the phenotype of another due to interaction of their gene products
        
        example one gene determines the pigment color with alleles B for black and b for brown and the other determines whether the pigment will be deposited in the hair
      - polygenic
        
        multiple genes independently affect a single trait
        
        quantitative characters
        
        are those that vary in the population along a continuum
        
        an example is height affected by over 180 genes
      - multifactorial
        
        traits that depend on multiple genes combined with environmental influences
        
        example hydrangeas grown in basic soil and hydrangeas of the same genetic variety grown in acidic soil
    - - not good subject for genetic research
      - generation time id too long
      - parents produce relatively few offsprings
      - breeding experiments are uacceptable
      - pedigree
        
        a family tree that describes the inheritance of a trait across generation
        
        can be used to make prediction of the future
        
        example the multiple and addition rule can be used to predict the future
      - behavior of recessive alleles
        
        only shows up in individuals homozygous for the allele
        
        carriers
        
        individuals who carry the recessive allele but are phenotypically normal
        
        example is albinism being a recessive condition
        
        characterised by a lack of pigmentation in skin and hair
        
        consanguineous matings increase the chance that both parents of a child carry same rare allele
        
        mating betwwen close relatives
      - genetic disorder
        
        cystic fibrosis
        
        results in defective chloride transport channels in plasma membrane
        
        symptoms include mucus buildup in some internal organs
        
        sickle cell disease
        
        caused when a single amino acid in hemoglobin protein in red blood cell is substituted
        
        symptoms include physical weakness, pain, organ damage
        
        dominantly inherited disorders
        
        example Dwarfism caused by rare dominant allele
        
        Huntington's disease is a degenerative disease of the nervous system