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Plant Genetics etc. - Coggle Diagram

- - - - Nx̌/nN⁰
  - - - Calculated by taking the sum of the offspring/individual column
    - - Calculate intrinsic growth rate (r)
      - Calculated by taking the natural log of the met reproductive rate divided by rhe mean generation time.
      - If r<0, the population size decreases
      - If r=1 population size des not change
      - R>1? Population size increase.
  - - - Take log¹⁰ of this value and plot against age to produce a figure.
- - - - Phenotype coded by genotype.
  - - - This significantly alters characteristics of a species.
- - - - allele frequency :
        
        num. of copies an allele in a population divided by the number (total) of alleles for that gene in a population.
      - genotype frequency
        
        number of individuals with a particular genotype in a population divided by the total number of individuals in a population
      - frequencies of dominant and recessive traits in populations add up to one.
  - - - changes in a population's gene pool from generation to generation
      - factors
        
        mutation
        
        change in one of the nucleic acids
        
        some are apparent in phenotype
        
        source of all new alleles
        
        must be in gametes to be inherited
        
        male pollen sperm
        
        female ovule egg
        
        natural selection
        
        1 allele selectively advantageous
        
        over time individuals with advantageous genotype are able to reproduce more and grow in numbers
        
        overall vigor of population grows, so does population.
        
        genetic drift
        
        random loss of alleles
        
        acts most strongly in small populations relative to large
        
        bottleneck effect
        
        large population diminished suddenly do to migration/natural catastrophe
        
        may increase in size again but unlikely to regain original diversity.
        
        migration
        
        movement of alleles into and out of a population
        
        immigration? into
        
        emigration? out of.
        
        can be impeded by the environment and life history. #
        
        repercussions for GMO and climate change, as well as specialization.
        
        nonrandom mating
        
        plants "choose" their mates
        
        pollinator vectors
        
        syndromes and pollinators
        
        some of the individuals reproduce more than others based on individual phenotypes.
        
        sexual selection
        
        male-male competition
        
        excess of pollen grains
        
        pollen tubes can interfere with one another
        
        female choice
        
        barriers on stigma surface preventing germination.
        
        polymorphism
        
        dimorphic
        
        2 phenotypes
        
        dominant-recessive systems
        
        polymorph = many phenotypes in a population
        
        can be due to single nucleotide polymorphism.
        
        adaptive radiation
        
        bottleneck from long distance dispersal
        
        followed by adaptive radiation
        
        artificial selection
        
        selection by humans
        
        increased frequency of desired trait, elimination of undesired traits.
        
        crop breeders have done this for thousands of years.
        
        brassica is an example.
- - - - R- ruderals
      - S- atress tolerators
      - C- competitors
    - - Abiotic
        
        Wind
        
        Fire
      - Biotic
        
        Arthropogens
        
        Pathogens
        
        Herbivory
    - - Growth inhibitors
        
        Toxins
        
        Temperature
      - Resource availability
        
        Light
        
        Nutrients
        
        Water
  - - - Resource-intensive fruits with investments in defense.
      - Perennials
      - Pretty stable habitats
      - Fluctuate around
        carying capacity
    - - Many, small fruits
      - Little investment in defense
      - Annuals
      - Weedy
      - Disturbed areas
      - Grow exponentially
  - - - Overshoot K, resulting in a dying off due to limited resources.
    - - Typical of a population that self-regulates and has a carrying capacity.
      - S shaped curve
    - - Unlimited resources
      - J-ahaped curve
- - - - during metaphase I, orientation of bivalents is random
      - during metaphase II, orientation of chromatid sisters is random
      - in general, the possibilities are 2n.
        
        humans with 46 chromosomes
        
        more possibilities with more chromosomes.
      - random placement.
    - - homologous chromosomes
      - resemnble each other in size, shape, and hereditary information.
      - each homolog is from a different parent.
      - interactions of genes on each set of chromosomes determines the genetic characteristics.
      - each chromosome has a partner
    - - "a little hug!"
      - during prophase I
      - synaptonemal complex forms
      - mixes the genes present in homologous chromosomes, results in new combinations not present in the chromosomes of the parent cells.
      - more diversity in genetics.
    - - promotes heterozygosity #
      - new combination of alleles from each parent
      - advantages
        
        genetic diversity
        
        bet-hedging to novel environments
        
        multiple deleterious alleles can be bunched together
        
        escape host-parasite negative impacts
      - pollination
        
        cross pollination vs self pollination
  - - - dominance
        
        each individual has a unique genotype
        
        genotypes is made up of alleles
        
        there is no guarantee that an allele will manifest
        
        phenotypes are determined by these alleles and the environment,.
        
        heterozygosity
        
        one of 2 genes has a detectable effect on an organism's appearance
        
        other gene has no discernable effect.
        
        homozygosity? both alleles are the same #
      - segregation
        
        alleles are segregated, separated, from one another during meiosis
        
        each gamete contains only one allele for each gene
        
        offfspring inherit two alleles for a gene
        
        one from each parent
        
        inherit a homologous chromosome
        
        during meiosis, 2 members of a gene pair separate from each other
        
        each gamete has equal chance to inherit either one of the genes,
        
        monohybrid cross
        
        way to visualize what happens in meiosis.
        
        punnett square
        
        visual representation of the offspring inheritance patterns
        
        monohybrid is a cross between two homozygous parents with different alleles.
      - independent assortment
        
        gene pairs that are not related segregate independently
        
        gene pairs that are not linked segregate independently
        
        evidence provided from a dihybrid cross?
        
        3:1 phenotypic ratio for each of the 2 alleles.
        
        dihybrid example
        
        bigger than monohybrid cross.
    - - incomplete dominance
        
        phenotypes of heterozygote is intermediate between those of parent homozygotes.
        
        snapdragons?
        
        red + white = pink.
      - multiple alleles
        
        many populations have more than 2 alleles for a particular locus.
        
        punnett square theoretical crossing works similar
        
        breeding experiments to determine dominance
        
        figuring out alleles is complex
      - mutations
        
        changes in the genetic makeup of an individual
        
        point mutation? single nucleotide change
        
        chromosome mutation? deletion
        
        types
        
        deletion - segments of chromosome are lost
        
        duplication - part of the chromosome has doubled #
        
        inversion - piece rotates 180*.
        
        translocation - exchange of parts between two nonhomologous chromosomes
        
        transposons - movable genetic element, and jumping genes,
      - no crossing over
        
        fail to mix alleles across homologs
        
        chromosome inherited same as parent
        
        only 2 gamete types possible rather than four.
        
        sort of a coin flip situation.
      - polygenetic inheritence
        
        multiple genes for one character
        
        phenotype is cumulative result of combined effects of many genes.
        
        example? abscisic acid.
        
        most traits are this way.
        
        continuous variation
      - epistasis
        
        one gene interacts with another
        
        may interfere or mask
        
        eg. digitalis petal color
        
        one gene impacts red intensity
      - linkage
        
        4 haploid genotypes, not produced in equal numbers.
        
        parentals more abundant.
        
        recombinants less abundant.
        
        linkage in clarkia
        
        selfer
        
        small petals
        
        physiologically escape
        
        seasonal droug #
        
        flower early
        
        outcrosser
        
        large petals
        
        late flower
        
        seasonal droug
        
        physiologically tolerant
      - pleiootropy
        
        single gene with multiple effects on the phenotype
        
        inheritance of a single gene which visibly influences several traits.
        
        ex. awn of wheat
        
        wheat with awns have bigger yields than those without.
      - polyploidy
        
        having more than 2 copies (2n) of a chromosome
        
        autopolyploidy
        
        failed meiosis
        
        self-fertilization
        
        allopolyploidy
        
        meiotic error
        
        mismatch during mating
        
        second mating creates matched paits.
        
        different species.
        
        examples?
        
        wheat. its a result of sequential hybrid doubling and quadrupling.
        
        original ancestral species has 14 chromosomes.
        
        durum wheat has 28 chromosomes and is tetraploid.
        
        bread wheat has 42 chromosomes and is hexaploid.
        
        strawberries
        
        chemically induced
        
        mutagen induced.
        
        prevent microtubule formation
        
        required for meiosis to occur properly.
        
        gives big ol fruits.
        
        produce diploid gametes.
        
        during fertilization 2 diploid gametes fuse resulting in tetraploif.
        
        evolutionary significance
        
        polyploid mask deleterious recessive alleles.
        
        relax selection pressure
        
        accumulate mutations that eventually result in beneficial trait
        
        2 groups of ancient duplications
        
        common ancestor of seed plants
        
        common ancestor of extant angiosperms
        
        allows for all these innovations through duplication mutation.