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Genetics (Mutations (any change in DNA (mutagen (causes mutations…

- - - - causes mutations
        
        chemicals
        
        UV light
        
        X rays
        
        Radiation
      - some mutagen repairing enzymes do exist
      - transposable elements
        
        causes of insertions and deletion mutations
        
        pieces of DNA that readily change their positions from one chromosome to another
        
        insertion sequences
        
        cutting insertion sequence out and replacing with DNA
        
        transposon
        
        caries genes that code for proteins not associated with transposition
  - - - deletion
        
        removal
      - insertion
        
        addition
      - inversion
        
        out in backwards
  - - - some may have no effect at all
        
        point mutations
        
        small insertions and deletions
      - some mutations in an exon may cause the gene to code for a protein whose active site is disrupted and can't function
      - statistically most mutations are harmful
  - - - example, leaf primordium cell
        
        leaves aren't involved in sexual reproduction, so mutation is not passed to offspring
  - - - longer genomes have a higher chance have of errors during replication
      - can not be perfectly effective or extremely efficient
- - - - ex.= crossing of different plant colors
        
        after first trait is studied, then more factors can be studied
        
        dihybrid or trihybrid crosses
        
        parents = parental generation
        
        offspring = F1, or first filial generation
        
        interbreeding = F2
        
        genetic symbols
        
        red flower = RR, and white =rr
        
        both homozygous
        
        RR= only R gametes
        
        rr= only r gametes
        
        pink flower of F1= Rr
        
        heterozygous
        
        produces R sperm and r egg or visa versa in equal numbers
        
        incomplete dominace
        
        neither parental trait dominates
      - shape
      - leaf structure
      - photosynthetic efficiency
      - Mendel mainly focused on monohybrid
  - - - or by crossing with another plant of the same genotype
        
        either route results in 50/50 chance of containing R or r allele
        
        not all zygotes are gentically similar
        
        RR
        
        25%
        
        rr
        
        25%
        
        Rr
        
        50%
        
        produces 3 types of F1
        
        Punnett squares used to see proportions of genotypes
        
        basis of modern genetics
        
        1:2:1 ratio discovered by Mendel
  - - - shows over recessive
        
        height example
        
        TT= tall
        
        homozygous dominant
        
        Tt= tall
        
        but has recessive allele for shortness
    - - height
        
        tt= short
    - - cross two heteros (Tt)
        
        1 TT: 2 Tt: 1 tt
        
        75% tall, and 25% short
        
        75% dominant character shown
  - - - cross a unknown genotype plant with a homozygous recessive
        
        results
        
        if TT then = 100% tall
        
        if Tt= 50% short, and 50% tall
        
        can be used to form pure-bred lines
        
        keeping genotypes separated
  - - - protein size =300 amino acids
        
        codon portions of mRNA = 300 codons with each containing 3 nucleotides
        
        gene= 900 nucleotides long
        
        gene may result many forms, or multiple alleles
        
        polymorphic
        
        X1, X2, X3, X4
        
        makes concept of dominance more complex
- - - - 9:3:3:1 ratio is created
  - - - crossing over between the two occurs during prophase 1
      - the further apart the genes are, the higher the chance for crossing over to occur
  - - - two genes become linked
- - - - alleles of parents passed to progeny equally
      - all genes in the nucleus
    - - zygote obtains all plastid and mitochondria genomes from maternal parent
        
        mitochondrion genetics are difficult to understand
        
        plastid genetics are easier to understand
        
        results depends on which plant is pollen and which is ovule plant
        
        also responsible for certain variegation
        
        presence of spots or sectors that are white, red, or orange on a plant that is otherwise green
  - - - genetically inherited mutations always result from recessive and present in homolygous condition
    - - affects basic metabolic functions then results in death very young
      - some gametes even die before fertilization
  - - - even ploidy level means plants can undergo meiosis and are fertile
      - odd means they are sterile like triploids
    - - two chromatids stay joined after second division of meiosis
- - - - allows entry of replicating factors
        
        one strand of the double helix becomes cut
        
        forms replicon bubble
        
        open helix allows free nucleotides to diffuse to regions of single strand
        
        pair with bases along strand
        
        primer RNA
        
        10 sequences long
        
        acts as substrate for DNA -synthesizing enzyme
        
        1 more item...
        
        replication fork
        
        DNA uncoiling
        
        replication forks run into adjacent replicons and all new pieces of DNA are ligated
- - - - 4 or 5 genes effect the same trait
        
        epistasis
        
        quantitative trait loci
        
        genes of other portions of DNA associated with such traits
        
        pleiotropic effects
        
        multiple phenotype effects of one mutation