Chapter 8: 8.1 More Complex Genetics [Blood Type, Pleiotropy, Epistasis and Polygenic Inheritance] Flashcards
What are the blood types that a human can have?
- Type A
- Type B
- Type AB
- Type O
What are blood types determined by?
- Type of carbohydrate added to a protein on the surface of red blood cells
- 3 different enzymes responsible for adding this carbohydrate
True or False:
The three different enzymes responsible for adding carbohydrates to proteins are encoded by the same alleles
False, they are encoded by three different alleles
Blood Type:
What enzymes are responsible for adding different carbohydrates?
- I(A) adds “A” type carbohydrate
- I(B) adds “B” type carbohydrate
- i does not add carbohydrates
True or False:
Blood type is determined by which alleles the person has
True
Blood Type:
Blood type alleles
* I(A)I(A)
Type A blood
Blood Type:
Blood type alleles
* I(A)i
Type A blood
Blood Type:
Blood type alleles
* I(A)I(B)
Type AB blood
Blood Type:
Blood type alleles
* I(B)I(B)
Type B blood
Blood Type:
Blood type alleles
* I(B)i
Type B blood
Blood Type:
Blood type alleles
* ii
Type O blood
Blood Type:
Distinguish blood types by the type of carbohydrates they have
- Type A blood: “A” type carbohydrates
- Type B blood: “B” type carbohydrates
- Type AB blood: “A” and “B” type carbohydrates
- Type O blood: No carbohydrates
Pleiotropy:
What can be the result of a mutation in a pleiotropic gene?
Can have a broad range of phenotypes associated with it
Pleiotropy:
Pleiotropic genes (Pleiotropy)
Can control multiple different seemingly unrelated traits
Phenylketonuria is an example of…
Pleiotropy
What is phenylketonuria?
Genetically inherited condition that has to do with levels of the amino acid phenylalanine
What is the genetic cause of phenylketonuria?
A mutation in the gene that codes for an enzyme responsible for breaking down phenylalanine into tyrosine
What does phenylketonuria lead to? (signs and symptoms)
Toxic build up of phenylalanine in the body and low levels of tyrosine
* Nerve damage, mental disorders
* Developmental problems (abnormal gait and posture)
* Seizures
* Skin rashes and fair skin
Epistasis
When two or more genes contribute to a phenotype, and the phenotype of one gene is altered by the presence of another
Alleles and genes can interact with each other to give…
Different phenotypes
True or False:
Epistasis is when one gene contributes to a phenotype
False, it is when TWO OR MORE GENES contribute to a phenotype
Polygenic Inheritance
Some traits are determined by the combination of multiple genes
* Known as polygenic inheritance
True or False:
Environment can have an effect on the phenotype
True, environment and genes both can determine phenotypes
