“Lesion3 (Les3)”By Jessica L. Johns& Erika M. BertelsenStudent Projects on Maize MutantsMiddle School Gifted Science ClassFall 2004 Mentorship ProgramMaize Genetics with Biologist H. BassSchool of Arts and Sciences (SAS) Charter SchoolLeon County School System, Tallahassee, FL

CreditsScience Teacher: Joan Crow, SAS Science TeacherFSU Mentor: Hank W. Bass, Assistant Professor of Biological Science, FSUAssistants: Bobbye Hill Biological Research Scientist, Bass lab, FSU

Debbie M. Figueroa, Graduate Student, Bass lab, FSUBrian C. Ring, Post-doctoral Research Associate, Bass lab, FSU

Additional thanks to: Julia Winter, SAS Math teacherAmber N. Brown, Graduate Student, Bass lab, FSU

LinksThe SAS school web page http://www.artsandsciences.leon.k12.fl.us/main/The SAS Mentorship Fall ‘04 page http://www.cytomaize.org/outreach/sas/The Maize-10-Maize project http://www.cytomaize.org/outreach/

Hank Bass laboratory home page http://bio.fsu.edu/bass/email contact: bass@bio.fsu.edu

Lesion3 (Les3)

By Jessica Johns &Erika Bertelsen

Lesion3 (Les3) JLJ, EMB, 1-13-05

Lesion3, what is it?

Lesion3 is a dominant genetic mutation inwhich dead spots (lesions) appear on theleaves of corn plants. The lesions do notappear on the leaves for about six weeks.

Some lesionson a leaf from aLes3 mutant plant

What Causes a Lesion?A lesion is caused by a genetic mutation.The basic pattern of DNA is coded with thenucleotides that are lettered A, T, G, and C.

A is always base-paired with TG is always base-paired with C

When there is a malfunction or skip in the Les2gene sequence it causes a mutation. The geneticmutation then causes a physical mutation which isexpressed as a visible lesion (phenotype) on theplants leaves.

Our Question

When we first planted ourseedlings we asked ourselvestwo questions, how many ofour plants would get lesions,and just how long our plantswould survive once theydeveloped lesions. As weobserved our plants over theweeks we found the answer.

Our Observations

Week 1Light green stems, small leaves, and no lesions.

Week 2Bottom leaves are a darker green, while the upperleaves are still light. The stems are purplish-red, andthere are slight lesions.

Week 3Plants are now large. No new lesions.

Week 4Twelve out of the sixteen plants have developedlesions. The other four are wild-type* in appearance.

* A wild-type is a normal-looking plant which shows no mutation.

Why are there wild types?

Lesion mutant: Ll or LLNormal: ll

Test-cross:Parents: (P1) Ll x ll

Offspring: (F1) Ll ll Ll ll

Notice that not all have lesions

Field Pictures of Les3 lesions

Our Answer

Only 12 of our 16 plants showed lesions.

The lesions which developed were notsevere, and we didn’t think they would affectthe plants health.

Our plants which got lesions did not die, butthey did become sick and in time they maywell die.

Reference

1976

RB Ashman & AJ Ullsturp

A Heritable, Noninfectious Necrosis ofMaize Leaves.

Journal of Heredity

Volume 67 Pages 220-222

Name: Lesion3 (Les3)

Locus: Chromosome 10(linkage map bin 10.06)

Field placard by:Jessica Johns & Erika Bertelsen

Middle School Mentorship, Fall 2004School of Arts and SciencesLeon County Charter SchoolTallahassee, FL

Field placard

A special thanks

We would like to offer a special thanksto…

Dr. Hank BassMs. Debbie FigueroaMs. Bobbye HillDr. Brian RingAnd of course our wonderful Ms. Crow

The end