Epistasis exam Flashcards
Terms in this set (26)
Epistasis
An inheritance pattern where one gene's product influences the phenotype of another gene.
What is the role of the H gene in human blood types?
The H gene produces a protein necessary for attaching A and B molecules to red blood cells.
Homozygous recessive for the H gene
An individual with two recessive alleles (hh) for the H gene, resulting in type O blood regardless of IA or IB alleles.
What happens if an individual is homozygous recessive for the H gene?
They will have type O blood, regardless of their IA or IB alleles.
What does the recessive allele for the H protein encode?
An inactive form of the H protein that does not connect A or B molecules to blood cells.
Phenotype
The observable characteristics or traits of an organism.
What is required for A molecules to be expressed on the surface of red blood cells?
A functional H protein, meaning the individual must have at least one capital H allele.
What does epistasis demonstrate in genetic interactions?
How one gene can mask the expression of another, highlighting the complexity of genetic interactions.
Connector molecule
The H protein that attaches A and B molecules to the surface of red blood cells.
What is the phenotype of an individual with IAIA and hh genotype?
Type O blood, due to the inactive H protein.
IAIB genotype with Hh
The individual will have AB blood type, as the functional H protein allows attachment of both A and B molecules.
What does an inactive H protein result in?
The inability to attach A or B molecules to red blood cells, leading to type O blood.
IAi genotype with HH
The individual will have type A blood, as the functional H protein allows attachment of A molecules.
What is the effect of epistasis on blood type inheritance?
It can cause inconsistencies, such as individuals with IA or IB alleles having type O blood if they are hh.
Hh genotype
An individual with one dominant and one recessive allele for the H gene, resulting in a functional H protein.
What is the role of the H protein in blood type expression?
It acts as a connector molecule necessary for attaching A and B molecules to red blood cells.
IAIB genotype with hh
The individual will have type O blood, due to the inactive H protein.
What does the term 'homozygous' mean?
Having two identical alleles for a particular gene.
IAi genotype with hh
The individual will have type O blood, due to the inactive H protein.
What is the significance of the H protein in epistasis?
It determines whether A and B molecules can be attached to red blood cells, affecting blood type.
IAIA genotype with Hh
The individual will have type A blood, as the functional H protein allows attachment of A molecules.
What is the result of having two lowercase h alleles?
An inactive H protein that does not connect A or B molecules, leading to type O blood.
IAIB genotype with HH
The individual will have AB blood type, as the functional H protein allows attachment of both A and B molecules.
IAi genotype with Hh
The individual will have type A blood, as the functional H protein allows attachment of A molecules.
What is the effect of a functional H protein on blood type?
It allows the attachment of A and B molecules to red blood cells, determining the blood type.
IAIA genotype with hh
The individual will have type O blood, due to the inactive H protein.