Lesion3 (Les3)

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Lesion3 (Les3)

• By Jessica Johns Erika Bertelsen

Lesion3 (Les3) JLJ, EMB, 1-13-05
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Lesion3, what is it?

• Lesion3 is a dominant genetic mutation in which
  dead spots (lesions) appear on the leaves of corn
  plants. The lesions do not appear on the leaves
  for about six weeks.

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What Causes a Lesion?

• A lesion is caused by a genetic mutation.
• The basic pattern of DNA is coded with the
  nucleotides that are lettered A, T, G, and C.
• A is always base-paired with T
• G is always base-paired with C
• When there is a malfunction or skip in the Les2
  gene sequence it causes a mutation. The genetic
  mutation then causes a physical mutation which is
  expressed as a visible lesion (phenotype) on the
  plants leaves.

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Our Question

When we first planted our seedlings we asked
ourselves two questions, how many of our plants
would get lesions, and just how long our plants
would survive once they developed lesions. As we
observed our plants over the weeks we found the
answer.
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Our Observations

• Week 1 Light green stems, small leaves, and no
  lesions.
• Week 2 Bottom leaves are a darker green, while
  the upper leaves are still light. The stems are
  purplish-red, and there are slight lesions.
• Week 3 Plants are now large. No new lesions.
• Week 4 Twelve out of the sixteen plants have
  developed lesions. The other four are wild-type
  in appearance.
• A wild-type is a normal-looking plant which
  shows no mutation.

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Why are there wild types?

• Lesion mutant Ll or LL
• Normal ll
• Test-cross
• Parents (P1) Ll x ll
• Offspring (F1) Ll ll Ll ll
• Notice that not all have lesions

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Field Pictures of Les3 lesions
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Our Answer

Only 12 of our 16 plants showed lesions. The
lesions which developed were not severe, and we
didnt think they would affect the plants health.
Our plants which got lesions did not die, but
they did become sick and in time they may well
die.
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Reference

1976 RB Ashman AJ Ullsturp A Heritable,
Noninfectious Necrosis of Maize Leaves. Journal
of Heredity Volume 67 Pages 220-222
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Field placard
Name Lesion3 (Les3) Locus Chromosome
10 (linkage map bin 10.06) Field placard
byJessica Johns Erika Bertelsen Middle
School Mentorship, Fall 2004 School of Arts and
SciencesLeon County Charter SchoolTallahassee,
FL
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A special thanks

• We would like to offer a special thanks to
• Dr. Hank Bass
• Ms. Debbie Figueroa
• Ms. Bobbye Hill
• Dr. Brian Ring
• And of course our wonderful Ms. Crow

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The end