Incomplete Dominance One allele does not over shadow the other they mix together Use RR RR RR Ex Carnations A red carnation mated with a white carnation makes a pink carnation ID: 181976
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Slide1
Complex Patterns of InheritanceSlide2
Incomplete Dominance
One allele does not over shadow the other, they
mix
togetherUse RR, R’R, R’R’Ex. CarnationsA red carnation mated with a white carnation makes a pink carnation.
Ex. Snapdragons
Ex. CarnationsSlide3
Cross a red snapdragon with a pink snapdragon:
Phenotypic Ratio:
Genotypic Ratio:
Parental Genotypes:Slide4
Cross a red snapdragon with a
white snapdragon
:
Phenotypic Ratio:
Genotypic Ratio:
Parental Genotypes:Slide5
Co-Dominance
Both alleles are expressed equally. One allele does not over shadow the other.
Use
HRHR HRHW HWH
WEx. Roan CattleRed and white hairs are presentEx. Some flowersSlide6
Cross a
roan cow with a roan bull
Phenotypic Ratio:
Genotypic Ratio:
Parental Genotypes:Slide7
Sex Linked
Traits that are carried on the X chromosome
Females need 2 recessive copies of the allele to express the trait, if they receive one they are a carrier.
Males only need one copy of the allele to express the trait, this is why sex linked traits are more prevalent in males.Use X and Y chromosomes with the allele as a subscript to represent the trait
Normal Female
XAXACarrier Female
XAXa
Affected FemaleX
a
X
aNormal MaleXAYAffected MaleXaYSlide8
Cross a
carrier female with a normal male
Phenotypic Ratio:
Genotypic Ratio:
Parental Genotypes:Slide9
Multiple Alleles & Co-dominance
In humans blood type is controlled by 3 alleles
A, B, O
A & B are co-dominant – O is recessiveType O: OO or ii Type A: AA / IA
IA (homozygous) AO / I
Ai (heterozygous)Type B: BB / IB
IB (homozygous) BO / I
Bi (heterozygous)
Type AB
AB / I
AIBSlide10
Blood Type
Blood Type That Can Be Received
Type of Antigens Present
Type of Antibodies Produced
A ( I
A
)
A and O
A antigens
B antibodies
B ( I
B
)
B and O
B antigens
A antibodies
O ( i )
Universal Donor
Only O
No antigens
A and B antibodies
AB ( I
A
I
B
) Universal Recipient
All types
A and B antigens
No antibodies
Blood TypesSlide11
Multiple Alleles
Traits that are controlled by one gene with several different alleles.
Ex. Coat color in Labs is controlled by 4 different alleles, 5 coat colors are possible.Slide12
Polygenic Traits
Traits that are carried on more than one gene.
Exs: hair color, skin color, height.
A a C c
B b