Ch 11-2 Flashcards
What is complete dominance?
When the phenotype of the heterozygote is identical to the dominant homozygote.
Incomplete dominance meaning
A type of inheritance where the heterozygote shows an intermediate phenotype between the two homozygotes.
What is codominance
When both alleles in a heterozygote are fully expressed, resulting in a phenotype showing both traits equally.
Explain pleiotropy
When one gene influences multiple phenotypic traits.
Explain epistasis
When the expression of one gene is affected by another gene.
Define polygenic inheritance
When multiple genes collectively affect a single trait, often resulting in a range of phenotypes.
What are quantitative characters
Traits that vary continuously across a spectrum rather than in an either/or manner.
What is multifactorial character
A trait influenced by both genetic and environmental factors.
Example of codominance
The MN blood group, where both M and N alleles are expressed equally.
What is the ABO blood group an example of?
Multiple alleles, with three allelic forms: A, B, and O.
How does Tay-Sachs disease demonstrate different dominance at different levels?
Complete dominance at the organismal level, incomplete dominance biochemically, and codominance molecularly.
What is an example of pleiotropy in humans?
Sickle-cell anemia, where one gene affects multiple traits like blood cell shape and oxygen transport.
How does environment impact phenotypes?
Environmental factors can influence gene expression, resulting in a range of phenotypic outcomes.
What does the term “quantitative characters” refer to in polygenic inheritance?
Traits like height or skin color that vary along a spectrum and are controlled by multiple genes.
What is the impact of epistasis on phenotype?
It can mask or alter the effect of other genes, as seen in Labrador coat colors.
Which term describes when a heterozygote shows a mix of both parental traits equally?
A) Complete dominance
B) Codominance
C) Incomplete dominance
D) Epistasis
B
In which inheritance pattern does the heterozygous phenotype appear as a blend of the two homozygous phenotypes?
A) Complete dominance
B) Codominance
C) Incomplete dominance
D) Epistasis
C
Which of the following describes a single gene that affects multiple traits?
A) Codominance
B) Pleiotropy
C) Epistasis
D) Polygenic inheritance
B
Which concept applies when a trait is influenced by multiple genes and shows a range of phenotypes?
A) Pleiotropy
B) Codominance
C) Polygenic inheritance
D) Complete dominance
C
What does the term “epistasis” describe?
A) Genes that separate independently
B) A gene affecting the expression of another gene
C) Dominant alleles masking recessive ones
D) Polygenic inheritance
B
Which of the following is NOT an example of incomplete dominance?
A) A pink flower from red and white parent flowers
B) A cow with both black and white patches
C) A blend of skin tones in humans
D) Intermediate seed shape in plants
B
In Tay-Sachs disease, which type of dominance is observed at the biochemical level?
A) Complete dominance
B) Codominance
C) Incomplete dominance
D) Epistasis
C
What is an example of multiple alleles in humans?
A) MN blood group
B) ABO blood group
C) Eye color
D) Sickle-cell disease
B
Which term refers to traits influenced by both genes and the environment?
A) Epistasis
B) Quantitative characters
C) Multifactorial characters
D) Codominant traits
C
