Unit H

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Unit H Applied Genetics in Agriculture and
Agriscience
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Sexual Reproduction Processes

• Fertilization
• Union of haploid cells in both plants and animals
• Occurs in the ovary of plants and the uterus of
  animals
• Embyro
• A fertilized egg/ovule that will grow to produce
  new offspring
• Ovary
• Organ responsible for the production of
  eggs/ovums in plants and animals.

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Sexual Reproduction in Animals

• Fertilization
• Occurs internally in most animals all mammals.
• Some fish and insects are exceptions
• Haploid Cells
• Male cells are spermatozoa (sperm), released in
  semen to aid in the process of fertilization
• Female cells are eggs, produced in the ovary,
  fertilized and developed within the uterus
• Females release eggs on a cycle (menstrual cycle)
  that varies in time length according to species.

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Sexual Reproduction in Plants

• Pollination
• The transfer of male pollen to the female
  reproductive organs
• Pollination must occur before fertilization
• Removal of the stamen is the first step in
  mechanical cross pollination
• Germination
• The initial vegetative growth of a seed

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Reproductive Parts of Plants

• Male THE STAMEN
• Anther top of the male part of a flower,
  contains pollen
• Filament long slender stock on which the anther
  sits
• Female THE PISTIL
• Stigma the swollen end of the pistil, sticky to
  receive the pollen
• Style stalk connecting the stigma to the ovary,
  pollen on the stigma
• Ovary produces and stores the ovums (seeds),
  and protects seeds during development
• 1 ovum I seed 1 ovary 1 fruit

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Reproductive Parts of Plants
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Types of Flowers in Plants

• Complete have all the parts of a flower
  (stamen, pistil, sepals, petals)
• Incomplete missing any part of the flower
• Perfect have all the reproductive parts of a
  flower (stamen and pistil)
• Imperfect missing any reproductive part of the
  flower (stamen, pistil, or any part of either)

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Asexual Reproduction Cloning

• 16.03

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Cloning in Agriscience

• Allows rapid production of large numbers of
  genetically identical organisms.
• Agriculturalists can quickly disseminate
  outstanding traits.

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Cloning in Agriscience

• Most often utilized for the culture of plants
  cheaper, easier process, and less political
  opposition.
• The ability to differentiate is more in plants
  than animals
• Tissue culture
• the production of plants from small amounts of
  vegetative material in an invitro environment
• an increasingly popular and effective method of
  plant production.

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Cloning in Agriscience

• Animals are cloned almost exclusively by the
  division of embryos.
• In recent years, diploid cells have been cloned,
  but the process is extremely expensive and
  results in high losses.
• Dolly the sheep was produced from mammary gland
  cells in a sheep

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Cloning in Agriscience

• Clones are genetically identical (the exact same
  DNA)
• Any genetic differences results from
  environmental factors
• Disease, nutrition, physical injuries, etc.

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Asexual Propagation of Plants

• 16.04 Demonstrate proper technique in simple
  asexual propagation of plants

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Stem Cuttings

• Section of the stem or a branch is cut, treated
  with rooting hormone, and placed in soil or water
  to encourage the development of roots.
• Should always be taken just above a node for best
  rooting
• Most common method
• Used for both woody and herbaceous plants.

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Stem Cuttings
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Air Layering

• Section of the stem or branch has the bark
  removed or slightly damaged and a rooting hormone
  applied.
• Area is then covered with soil wrapped cellophane
  until well developed roots can be seen through
  the plastic
• Branch or stem is cut below the roots only after
  roots have fully developed.

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Air Layering
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Tissue Culture

• Common method using extremely small amounts of
  plant material
• Often uses meristem tips
• The tip of a branch where most active growth is
  occurring
• Tissue is removed from the plant, sterilized and
  cultured on agar in aseptic conditions
• Meristematic tissue develops shoots, is
  transferred to another media to develop
  adventitious roots, is hardened off, and finally
  transferred to soil.

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Division

• Method of plant propagation conducted by
  physically separating a plant into several
  smaller plantlets
• Often used for grasses and lilies
• A variation is the production of non-tunicate
  bulbs from scales
• Each scale must contain a part of the bottom of
  the bulb, the basal plate

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Division
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Grafting

• Process of removing plant material from one plant
  for incorporation into another plant
• Often used with fruit trees to create dwarf
  varieties
• Two parts
• Scion top portion of a graft that will form the
  main part of the plant
• Rootstock bottom portion of the graft that
  usually controls growth habit (size of the plant)
  but produces no vegetation

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Grafting

• Budding is related to grafting
• Instead of using a scion, exchange of plant
  material is accomplished with a single bud
• Scion and rootstock remain genetically distinct
  even after combination

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Grafting
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Other Methods

• Leaf Cuttings
• Root Cuttings

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Transgenic Organisms

• 16.05 Explain methods of gene insertion used in
  the creation of transgenic organisms

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Characteristics

• Can potentially be created using genes from ANY
  living organism
• The trick is finding a method for insertion and
  successful expression
• Genetically modified organisms (GMOs) transmit
  inserted genes at the same rate as naturally
  occurring genes
• Once a gene is inserted, it can be passed on
  through sexual reproduction

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Steps in Creating a GMO

• Develop a Purpose/Goal
• Transmission of genes from one organism to
  another is both expensive and potentially
  dangerous
• Expectations for work should be laid out
  carefully
• DNA must be extracted from the target organism
  and the specific gene to be introduced isolated
  utilizing restriction enzymes

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Steps in Creating a GMO

• Vectors are used from the transmission of genes
• Viruses make good vectors, as they often insert
  DNA into organisms they affect
• Plasmids are the viruses most often used as
  vectors
• Plasmids can store large strands of DNA or even
  one or more chromosomes
• Some vectors can transmit genes simply through
  contact with target cells in a liquid solution or
  by microinjection.

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Steps in Creating a GMO

• Isolated DNA is inserted into the new organism
  by
• Micromanipulation
• Isolated DNA segment is injected into a target
  cell utilizing a microscopic syringe under high
  magnification
• Most common
• Biolistics
• Uses a gene gun to fire gold plated .22 caliber
  shells that have been covered with the target
  gene into a mass of plant cells
• Most often used for plants, as cell mortality is
  high

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Micromanipulation
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Biolistics