MY STEED

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MY STEED
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Lecture 17
Regression and Heritability
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Covariance Statistics
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Covariance Statistics

• Correlation

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Covariance Statistics

• Correlation
• Regression -- the change in one variable per
  unit change in another variable

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Regression
?y
?x
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Regression
?y
?x
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Regression
?
?y
?x
1 unit
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Regression
by on x ?x,y ?x2
bx on y ?x,y ?y2
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Regression
by on x ?x,y ?x2
bx on y ?x,y ?y2
by on x the slope of the line in the graph
on previous slide.
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Example Beef weaning weight 7 months ?ww
600 yearling weight 12 months ?yw 1100
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Example Beef weaning weight 7 months ?ww
600 yearling weight 12 months ?yw 1100 ?2ww
1600 ?2yw 14400 ?ww, yw 4000
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Example Beef weaning weight 7 months ?ww
600 yearling weight 12 months ?yw 1100 ?2ww
1600 ?2yw 14400 ?ww, yw 4000 rww, yw
4000 .833 1600 14400
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Example Beef weaning weight 7 months ?ww
600 yearling weight 12 months ?yw 1100 ?2ww
1600 ?2yw 14400 ?ww, yw 4000 rww, yw
4000 .833 1600 14400 byw on ww
4000/1600 2.5
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Regression
2.5
?y
?x
1 unit
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Regression Prediction Equation
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Regression Prediction Equation

y ?y by on x (x - ?x)
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Regression Prediction Equation

y ?y by on x (x - ?x)
Individual 650 lbs yw 1100 2.5 (650 - 600)
1225

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Prediction
yw
1225
1100
ww
600
650
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Prediction
yw
1100
ww
600
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Genetic Parameters
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Genetic Parameters
Start with ?2P, why do records vary?
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Genetic Parameters
Start with ?2P, why do records vary? P1 ? G1
E1 P2 ? G2 E2
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Genetic Parameters
Start with ?2P, why do records vary? P1 ? G1
E1 G1 ? G2 P2 ? G2 E2 E1 ? E2
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Genetic Parameters
?2P ?2G ?2E
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Genetic Parameters
?2P ?2G ?2E ?2G variance due to
genotypes
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Genetic Parameters
?2P ?2G ?2E ?2G variance due to
genotypes ?2E variance due to
environment
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Genetic Parameters
Consider ?2G
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Genetic Parameters
Consider ?2G G BV DOM EPI ?2G ?2BV
?2DOM ??2EPI
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Genetic Parameters
Consider ?2G G BV DOM EPI ?2G ?2BV
?2DOM ??2EPI ?2BV ?2A (breeding value
variance or additive genetic variance)
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Heritability (h2)
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Heritability (h2)

• broad sense
• h2B ?2G 0 lt h2B lt 1
• ?2P

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Heritability (h2)

• broad sense
• h2B ?2G 0 lt h2B lt 1
• ?2P
• narrow sense
• h2 ?2BV 0 lt h2 lt h2B lt 1
• ?2P

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Heritability estimates for traits in The Seeing
Eye Breeding Program
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Selection Response for DJD
Number Radiographed
Generation Class
Percent
271 793 533 453 460 145 2,655
1 2 3 4 5 6 Total
26.6 21.3 20.3 4.2 2.8 0.7
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Name this person
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3
1
2
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Name this person
CALS Dean Susan Henry
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Canandaigua
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1
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Senaca
Cayuga
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Genetic Control versus Heritability
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Genetic Control versus Heritability

• ?2G and ?2BV exist if there is polymorphism at
  the loci involved in controlling the trait that
  impacts performance.

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Genetic Control versus Heritability

• ?2G and ?2BV exist if there is polymorphism at
  the loci involved in controlling the trait that
  impacts performance.
• When h2 0 gt no difference among breeding
  values but still could be substantial genetic
  control.

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Types of Traits
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Types of Traits

• One measurement taken -- birth weight

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Types of Traits

• One measurement taken -- birth weight
• Multiple measurements taken -- litter size, milk
  yield

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Genetic Parameters
Consider ?2E
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Genetic Parameters
Consider ?2E
E -- permanent and temporary environment E PE
TE
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Genetic Parameters
Consider ?2E
E -- permanent and temporary environment E PE
TE PE -- influences all records on an individual
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Genetic Parameters
Consider ?2E
E -- permanent and temporary environment E PE
TE PE -- influences all records on an
individual TE -- influences a single record,
different TE for each record
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Genetic Parameters
Consider ?2E
E -- permanent and temporary environment E PE
TE PE -- influences all records on an
individual TE -- influences a single record,
different TE for each record ?2E ?2PE ?2TE
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Dr. Bulter
Dr. Everett
Dr. Bauman
Drs. Henry and Novakovic
Rowdy
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What is my dogs name?
Guess the name of my dog.
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Student Livestock Show

• Leading animals
• Grooming animals
• Teaching animals tricks

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Leading
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Grooming
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Tricks, catching ball in mouth