Relationships

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Lecture 19
Relationships
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Relationships

• Related animals have genes in common

3
Relationships

• Related animals have genes in common
• Causes -- resemblance in appearance --
  similarity in performance

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Relationships

• Related animals have genes in common
• Causes -- resemblance in appearance --
  similarity in performance
• Use additive genetic relationship (ax,y) to
  quantify the degree to which two animals are
  related.

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Noninbred Population

• ax,y is equivalent to the fraction of genes in x
  and y that are identical by descent.

6
Noninbred Population

• ax,y is equivalent to the fraction of genes in x
  and y that are identical by descent.
• Identical by descent means exact replicas of
  each other, the same DNA.

7
Noninbred Population

• ax,y is equivalent to the fraction of genes in x
  and y that are identical by descent.
• Identical by descent means exact replicas of
  each other, the same DNA.
• Alike in state -- the same allele but not
  originating from a common ancestor.

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Animal I bB
Animal J Bb
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Questions
What building the office of the president of the
university? What Building houses the Dean of the
Ag school? F.B. Morrison (Morrison Hall) was
famous for his research in which discipline
Nutrition, Genetics or Physiology.
10
Questions
What building the office of the president of the
university? What Building houses the Dean
of the Ag school? F.B. Morrison (Morrison Hall)
was famous for his research in which discipline
Nutrition, Genetics or Physiology.
Day Hall
Roberts hall
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Lineage (noninbred)
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Lineage (noninbred) 1) Parent- offspring P gt O
aP,O 1/2
1/2
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Lineage (noninbred) 1) Parent- offspring P gt O
aP,O 1/2 2) Grandparent GP gt P gt O aGP,O
(1/2)2 1/4
1/2
1/2
1/2
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Lineage (noninbred) 1) Parent- offspring P gt O
aP,O 1/2 2) Grandparent GP gt P gt O aGP,O
(1/2)2 1/4 3) Any ancestor, y , t generations
back in the pedigree ax,y (1/2)t
1/2
1/2
1/2
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Collateral Relatives (noninbred)
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Collateral Relatives (noninbred)

• Animals related through common ancestors.

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Collateral Relatives (noninbred)

• Animals related through common ancestors.

1) Half sibs maternal -- same dam paternal
-- same sire DAM 1 SIRE DAM
2 O1 O2
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Collateral Relatives (noninbred)

• Animals related through common ancestors.

1) Half sibs maternal -- same dam paternal
-- same sire DAM 1 SIRE DAM
2 O1 O2
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Collateral Relatives (noninbred)
O1 gt sire gt O2 aO1, O2 (1/2)2 1/4
1) Half sibs maternal -- same dam paternal
-- same sire DAM 1 SIRE DAM
2 O1 O2
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Collateral Relatives (noninbred)
2) Full sibs -- both parents the
same SIRE DAM O1 O2 O1 ?
sire ? O2 (1/2)2 O1 ? dam ? O2 (1/2)2 aO1,O2
(1/2)2 (1/2)2 1/2
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Collateral Relatives (noninbred)
2) Full sibs -- both parents the
same SIRE DAM O1 O2 O1 ?
sire ? O2 (1/2)2 O1 ? dam ? O2 (1/2)2 aO1,O2
(1/2)2 (1/2)2 1/2
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Collateral Relatives (noninbred)
2) Full sibs -- both parents the
same SIRE DAM O1 O2 O1 gt
sire gt O2 (1/2)2 aO1,O2 (1/2)2 (1/2)2
1/2
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Collateral Relatives (noninbred)
2) Full sibs -- both parents the
same SIRE DAM O1 O2 O1 gt
sire gt O2 (1/2)2 O1 gt dam gt
O2 (1/2)2 aO1,O2 (1/2)2 (1/2)2 1/2
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Collateral Relatives (noninbred)
2) Full sibs -- both parents the
same SIRE DAM O1 O2 O1 gt
sire gt O2 (1/2)2 O1 gt dam gt
O2 (1/2)2 aO1,O2 (1/2)2 (1/2)2 1/2
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Collateral Relatives (noninbred)
3) Cousins SIRE DAM MATE P1
P2 MATE X Y
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Collateral Relatives (noninbred)
3) Cousins SIRE DAM MATE P1
P2 MATE X Y X ? P1 ? SIRE ? P2 ?
Y (1/2)4 1/16
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Collateral Relatives (noninbred)
3) Cousins SIRE DAM MATE P1
P2 MATE X Y X ? P1 ? SIRE ? P2 ?
Y (1/2)4 1/16 X? P1 ? DAM ? P2 ? Y (1/2)4
1/16
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Collateral Relatives (noninbred)
3) Cousins SIRE DAM MATE P1
P2 MATE X Y X ? P1 ? SIRE ? P2 ?
Y (1/2)4 1/16 X? P1 ? DAM ? P2 ? Y (1/2)4
1/16 aX,Y (1/2)4 (1/2)4 1/8
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Inbreeding

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Inbreeding

• Results from mating related animals

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Inbreeding

• Results from mating related animals

SIRE MATE daughter X
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Inbreeding

• Results from mating related animals

SIRE MATE daughter X asire, daughter 1/2
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Inbreeding
Quantifying inbreeding Fx inbreeding
coefficient
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Inbreeding
Quantifying inbreeding Fx inbreeding
coefficient P(both alleles at a locus are
identical by descent)
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Inbreeding
Quantifying inbreeding Fx inbreeding
coefficient P(both alleles at a locus are
identical by descent) (1/2) aparents
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Inbreeding

• Results from mating related animals

SIRE MATE daughter X
Fx (1/2) aS,D 1/4 (every fourth locus has
exact replicas at each chromosome) O lt F lt 1
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Rule Animals relationship to itself ax,x
1 Fx
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Rule Animals relationship to itself ax,x
1 Fx means that 0 lt a lt 2
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Correlation Between Breeding Values

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Correlation Between Breeding Values
Rx,y ax,y ax,x ay,y Rx,y Coefficient
of Relationships
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Correlation Between Breeding Values
Rx,y ax,y ax,x ay,y Rx,y Coefficient
of Relationships Rsire, x 3/4 .75
.67 (5/4) 1 1.12
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Correlation Between Breeding Values
Rx,y ax,y ax,x ay,y Rx,y Coefficient
of Relationships Rsire, x 3/4 .75
.67 (5/4) 1 1.12
0 lt Rx,y lt 1
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Lecture 20
Selection
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Selection for quantitative traits
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Selection for quantitative traits 1) Estimate
merit (BVs)
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Selection for quantitative traits 1) Estimate
merit (BVs) 2) Determine accuracy of
estimation
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Selection for quantitative traits 1) Estimate
merit (BVs) 2) Determine accuracy of
estimation 3) Predict response to
selection
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Assessment of Genetic Merit
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Assessment of Genetic Merit
Ancestors Sire Dam Sibs Sibs Indivi
dual (i) Progeny Future Descendants
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Assessment of Genetic Merit
Every animal shares genes in common with animal i.
Ancestors Sire Dam Sibs Sibs Indivi
dual (i) Progeny Future Descendants
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Genetic Evaluation Examples
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Genetic Evaluation Examples
-- combine all information weighted
appropriately for the source -- degree of
relatedness is important
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Genetic Evaluation Examples
1) n records on one animal, i or a
relative 2) 1 record on each of q equally
related relatives 3) pedigree index
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Estimation of BVs
-- obtained as a regression of a phenotypic
deviation
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Estimation of BVs
-- obtained as a regression of a phenotypic
deviation Phenotypic deviation -- records
deviated from a mean
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Estimation of BVs
-- obtained as a regression of a phenotypic
deviation Phenotypic deviation -- records
deviated from a mean Regression -- BV on
the phenotypic deviations