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USEFUL MUTANTS Heritable changes can result in a useful novel phenotype, i.e., a new allele.

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USEFUL MUTANTS USEFUL MUTANTS Heritable changes can result in a useful novel phenotype, i.e., a new allele.
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Page 1: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

USEFUL MUTANTSUSEFUL MUTANTS

Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Page 2: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Other Kinds

Page 3: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Some “not bad” Mutants

Page 4: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Sweet Corn

Single gene mutations in several different starch biosynthesis genes have been introduced into tender, flavorful corn to produce the sweet corn we eat today -Instead of transferring sugars into starch, they accumulate ‘sweetness’.

Shrunken (Supersweet), sugary, sugary enhancer, amylose extender.

Page 5: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Ornamental Corn

Single gene mutations in the anthocyanin (pigment) production pathway lead to the colored kernels we see on an ear of Indian corn.

Page 6: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Waxy Corn

A mutation in the waxy gene is used in production of tapioca and other gelling starch products.

Page 7: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

High-lysine Corn

A mutation in the opaque2 gene results in increased levels of the essential amino acid, lysine. Quality Protein Maize (QPM).

Page 8: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

o2, opaque endosperm: endosperm soft and opaque; high lysine content; regulates b-32 protein. Photo: seed from a selfed ear segregating for opaque kernels in transmitted light showing opaqueness of mutant kernels.

Page 9: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

And of course --

Disease resistance Insect resistance

Glossy mutants Flowering time Cytoplasmic male sterility Nutritional changes “Value-added” changes

Page 10: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Mutations and Co-evolution

Variations usually exist in nature. Co-existing species experience mutual selection.

Page 11: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.
Page 12: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Domestication by Culture

Suppression of ‘Wild’ Traits Seed scattering Mixed timing Hard-shelled seeds

Mutation/Selection of ‘Desired’ Traits Packaging Convenience Storability Processing

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Domestication in Wheat

DIVERGENCE, CROSSING, SELECTION

Earliest cultivated and wild wheat, with the 7-chromosome A genome (left), crossed with another, with the B genome, (third) about 8000 BC. The result was durum wheat (emmer = PASTA WHEAT), fourth in this photo. Emmer crossed with wild goat grass (fifth) and gave rise to the staff of life (BREAD WHEAT), sixth. The combination, AABBDD, 7x3 = 21 chromosomes, is productive and high in food quality.

Page 19: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.
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Ninetieth birthday of the Father of the Green Revolution, Nobel Peace Prize Laureate Norman Borlaug

http://www.cimmyt.org/english/webp/support/news/borlaug_90.htm

Dwarf Wheat Opened Doors

Page 21: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.
Page 22: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.
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New Wheats a la Nature

Deliberate employment of diversity in collections. Crosses of AABB with diverse DD and others.

Page 24: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.
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http://www.maizegdb.org/cgi-bin/imagebrowser_phenotypes.cgi

Mutant Images for Maize

Page 28: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Ramosa tassel and ear

Page 29: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Terminal ear1

Page 30: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Teopod2, Tunicate1

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White pollen1 (bursting)

Page 32: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Virescent1

Page 33: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

Directed Transposon Tagging

Yellow seed have tagged si1 allele (Si1 y1/si1-mum Y1)Grow plants from yellow seed and backcross to si1 y1/si1 y1. Plant out seeds, score for silky vs normal tassel phenotype. Prepare DNA from leaves of each type.

An example---cloning the male sterile silky1 (si1) gene using Mutator.

si1 y1/si1 y1 X Si1 Y1/Si1 Y1, Mu-active(white seed/silky tassel) X (Yellow seed/normal tassel)

Perform co-segregation analysis to identify transposon linked to your mutant phenotype.

all Yellow seed (y1/Y1)

si1 y1/Si1 Y1 (99.99%) Normal Phenotypesi1 y1/si1-mum Y1 (rare mutant 1/10000)

X Si1 y1/Si1 y1

Page 34: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

(normal tassel)Southern Blot Hybridized with Mu1 Probe

(silky tassel (si1/si1-mum))

Page 35: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

M0M0

M1M1

bz1*bz1*

sh1*sh1*

C1 sh1 bz1C1 sh1 bz1Lyophilize

d leaf disks

Lyophilized leaf disks

DNADNA

M2M2

Random intermating

Random intermating

Bulk SeedBulk SeedMinimum

criteria: ≥50 M2 seed with

≥60% germination

Minimum criteria: ≥50 M2 seed with

≥60% germination

Maize Genetics

Stock Centerfor

distribution

Maize Genetics

Stock Centerfor

distribution

Grow-outs

open to the

general public

Grow-outs

open to the

general public

Forward screens

for specific traits of interest

Forward screens

for specific traits of interest

M3M3

EMS treat pollenEMS treat pollen

TILLING = Targeting Induced Limited Lesions IN Genomes

c1 Sh1 Bz1c1 Sh1 Bz1

Make mutant populationMake mutant population

Page 36: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

DNA prepared and equal amounts of each sample arrayed to microtiter wells, then these 8-fold pooled

IR-labeled primers create double end-labeled fragments

Page 37: USEFUL MUTANTS  Heritable changes can result in a useful novel phenotype, i.e., a new allele.

IR700 IR800

200 bp

95bp

Bands of complementary size are visible, one in each image channel, corresponding to singly end-labeled fragments cleaved by CELI at the mutation site.

Mutant individuals identified from pools, sequenced. Information and analysis returned to User, along with Stock Center numbers for ordering seed.


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