Mendelian Inheritance

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CSS/Hort431 Plant Genetics Recitation Mendelian
inheritance
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Heart disease, high cholesterol, obesity

• Eating barley can help!
• A principal active ingredient is Beta glucan, a
  complex carbohydrate found in soluble fiber
• Barley can be higher in Beta glucan than any
  other grain

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High beta glucan varieties would be good but.

• Breeding for beta glucan per se is made
  complicated by quantitative inheritance
• The recessive (waxy starch) allele at the GBSS
  locus has a pleiotropic effect - it increases
  beta glucan
• GBSS is cloned and therefore the DNA sequence
  differences between waxy (wx) and non-waxy (Wx)
  be used as a basis for marker assisted selection

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What is the candidate gene for waxy?
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What cause the mutation?
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Result of the mutation
Glucose
GBSSI
Amylose
Amylopectin
Starch
90 amylopectin vs. 75 wild type
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en ScoScoring alleles at the Waxy locus
non-waxy
waxy
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Hull-less (naked) varieties could make grain
processing easier..

• Breeding for naked seed is not difficult - if
  you are willing to wait for plants to mature
• Nud_ genotypes are hulled nudnud are hull-less
• The Nud gene has not been cloned - yet!

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Hulled and hulless (naked)
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Wx and Nud are on the same chromosome

• But they are far enough apart to show independent
  assortment (no linkage)

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• Oregon Wolfe Barley Map
• 187 classical loci

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Lets get some practical experience in segregation
analysis !!!!
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Wx vs. wx and Nud vs. nud data are from a doubled
haploid populationThe expected segregation
ratio is..If it were a backcross?An F2?
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