Transcript jack of diamonds represents the gene for purple pigmentation

Agents that cause mutations are known as mutagens.
•Radiation
•Viruses
•Transposons
•Mutagenic chemicals
Chemical mutagens include aflatoxin (from mold), caffeine (found in
coffee and colas), LSD (lysergic acid diethylamide; a hallucinogenic
drug), benzo(a)pyrene (found in cigarette and coal smoke), Captan (a
fungicide), nitrous oxide (laughing gas), and ozone (a major pollutant
when in the lower atmosphere).
•Errors may also occur during meiosis or DNA
replication. They can also be induced by the organism
itself, by cellular processes such as hypermutation.
Base-pair substitution:
One base is wrongly paired with another (adenine to cytosine)
during replication.
Possible outcome is a different amino acid may replace another
during protein synthesis, changing the resulting protein. People
with sickle-cell anemia have this occur
Mom fed the dog for Tad who was out all day
Mop fed the dog for Tad who was out all day
Insertions/Deletions: (Frameshift Mutation)
One extra base is inserted, or deleted into a gene region.
Remember this insertion or deletion can completely change the
three-base codon/anticodon sentence.
Mom fed the dog for Tad who was out all day.
Mof edt hed ogf orT adw how aso uta lld ay?
Transposons/Transpositions:
When one or multiple bases jump around within the genome,
moving spontaneously from one location to another in the same
DNA molecule (or even to a different one)
Mom out the dog for Tad who was fed all day.
Sometimes called “Jumping Genes”
Transposons are genes that move from one location to another on a chromosome. If the
transposon moves to a position adjacent to a pigment-producing gene, the cells are unable
to produce the purple pigment. This results in white streaks or mottling rather than a
solid purple grain. The duration of a transposon in this "turned off" position affects the
degree of mottling. If the pigmentation gene is turned off long enough by a transposon,
the grain will be completely unpigmented.
The reddish streaks on these corn grains are caused by transposons.
Grains of Indian corn come in different colors, such as purple, yellow and
white. Sometimes the kernels are streaked, or mottled. The movement of
transposons on chromosomes may result in colored, non-colored and
variegated grains The explanation for this phenomenon involves "jumping
genes" or transposons, and earned Dr. Barbara McClintock the Nobel Prize
in Medicine in 1983 for her life-long research on corn genetics.
The different cards represent a linear sequence of genes on
a chromosome. The ace of spades represents a transposon
that moves to different positions on the chromosome. The
jack of diamonds represents the gene for purple pigmentation
in the corn grain. When the transposon (ace of spades) moves
to a position adjacent to the gene for pigmentation (jack of
diamonds), the pigmentation gene is blocked and no purple is
synthesized (white area). When the transposon moves away
from the gene for pigmentation, pigment can again be coded
for.
Transposons may also have a profound effect on embryonic
development and tumor formation in animal cells.
• Oncogenes (genes that cause tumors) may be activated by
the random reshuffling of transposons to a position
adjacent to the oncogene.
• Transposons may also be useful in genetic engineering with
eukaryotic cells, by splicing in transposons to activate
certain genes.
• The implications from Barbara McClintock's discovery of
transposons may be far-reaching and as significant as
Watson and Crick's discovery of the structure of DNA.
http://waynesword.palomar.edu/transpos.htm