Download Complex Inheritance Notes Name: • Some alleles are neither nor

Complex Inheritance Notes
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Name:___________________________
Some alleles are neither _________________ nor ________________, and many traits are controlled
by multiple alleles or multiple genes.
So special rules must be used for these cases:
– _________________________________________________________
– _________________________________________________________
– _________________________________________________________
– _________________________________________________________
– _________________________________________________________
Also __________________________ inheritance – we’ll get to that a bit later!
Incomplete Dominance
• __________________________ allele is dominant.
• The heterozygous phenotype is somewhere ___________________ the two
homozygous phenotypes.
• Example: Four o’clock flowers
Your Turn!
• In Australia there is a creature known as wild dogs or dingoes. It comes in three
colors, black, grey, and white. This trait is controlled by a single gene with
incomplete dominance. A homozygous (BB) individual is black, a homozygous
(bb) individual is white, and a heterozygous (Bb) individual is grey.
• What would be the genotypes and phenotypes of the offspring if a black dingo
were crossed with a white dingo?
Codominance
• ____________________ alleles are dominant.
• Both alleles appear in the phenotype ___________________________________________.
• Each allele produces both types of _________________________, so they both appear.
• Example: A black chicken mating with a white chicken will create an erminette chicken (also known as
checkerboard).
Your Turn!
• A white cow (WW) mates with a brown cow (RR) to create a roan calf (RW).
This trait is controlled by a single gene with codominance. Suppose this roan
calf grows up to mate with another roan cow.
• What would be the genotypes and phenotypes of the offspring?
Multiple Alleles
• In a population, there might be more than 2 alleles for
_______________________________
• Any individual cannot have more than 2 alleles, even if many more exist
in their gene pool.
• One from the ___________ and One from the ________________
• Example: Laborador coat color, mouse coat color, human blood types
Blood Typing
• Human blood works of a system of ___________________________ with
the AB blood type and
__________________________________________ due to three alleles, A, B and O.
• ______________________________________ is famous for his blood preservation methods.
Your Turn!
• A man is concerned about if he is the father of
a child. He has blood type B and the mother
has blood type O. The child’s blood type is A.
• Is he the father of this child?
Conclusion: ____________________________
Lethal Alleles
• This defies Mendel’s laws of 3:1 because one of the _______________________ results in a lethal
(deadly) Phenotype.
• Also called ______________________________________________.
• Example: Sickle Cell Anemia – the offspring that gets C1C1 will die immediately from the blood
disorder.
– How do lethal alleles still persist in the population if those with lethal alleles die before birth!?
– What disease is susceptible to sickle cell?
Polygenic Traits
• Instead of a trait being controlled by a single pair of
___________________ ___________________, some traits are
controlled by several ________________.
– Poly = many
– Genic = genes
• You get more a ________________________________ of diversity
• Examples: Skin color, hair color, etc…
• Example: AaBBCcddEe