Podcast
Questions and Answers
Which inheritance pattern is characterized by the presence of a recessive trait requiring two copies of the recessive allele for phenotype expression?
Which inheritance pattern is characterized by the presence of a recessive trait requiring two copies of the recessive allele for phenotype expression?
- Y-linked
- Autosomal dominant
- X-linked dominant
- Autosomal recessive (correct)
What type of allelic interaction occurs when both alleles in a heterozygote are expressed equally, resulting in a phenotype that is a blend of both traits?
What type of allelic interaction occurs when both alleles in a heterozygote are expressed equally, resulting in a phenotype that is a blend of both traits?
- Codominance
- Multiple allelism
- Autosomal dominance
- Incomplete dominance (correct)
Which inheritance pattern would most likely affect males more than females, as it is located on the X chromosome and is inherited in a recessive manner?
Which inheritance pattern would most likely affect males more than females, as it is located on the X chromosome and is inherited in a recessive manner?
- Y-linked
- X-linked recessive (correct)
- Autosomal recessive
- X-linked dominant
Which of the following best describes a scenario where three or more alleles exist for a single trait within a population?
Which of the following best describes a scenario where three or more alleles exist for a single trait within a population?
In which type of inheritance pattern would a daughter inherit the trait from either one of her parents, but sons would inherit it only from their mother?
In which type of inheritance pattern would a daughter inherit the trait from either one of her parents, but sons would inherit it only from their mother?
Flashcards are hidden until you start studying
Study Notes
Inheritance Patterns of Traits
-
Autosomal Recessive:
- Trait expressed only when an individual has two copies of the recessive allele.
- Individuals with one dominant allele are carriers and display no symptoms.
- Examples include cystic fibrosis and sickle cell anemia.
-
Autosomal Dominant:
- Trait expressed with just one copy of the dominant allele.
- Affected individuals can pass the trait to offspring with a 50% chance.
- Examples include Huntington’s disease and Marfan syndrome.
-
X-Linked Recessive:
- Trait linked to genes on the X chromosome; predominantly affects males.
- Males with one affected X will express the trait, while females need two affected X chromosomes.
- Common conditions include hemophilia and Duchenne muscular dystrophy.
-
X-Linked Dominant:
- Trait expressed in individuals with one copy of the dominant allele on the X chromosome.
- Both males and females can be affected, but males may exhibit more severe symptoms.
- Conditions include Rett syndrome and X-linked hypophosphatemia.
-
Y-Linked:
- Traits associated with genes on the Y chromosome, affecting only males.
- Passed from father to son with a 100% inheritance rate.
- Examples include certain forms of male infertility and Y chromosome microdeletions.
Allelic Interactions
-
Incomplete Dominance:
- Heterozygous phenotype is a blend of both alleles, clearly different from both homozygous phenotypes.
- Example: In snapdragons, crossing red and white flowers results in pink flowers.
-
Codominance:
- Both alleles are fully expressed in the phenotype of heterozygotes.
- Example: Blood type AB expresses both A and B antigens.
-
Multiple Allelism:
- More than two alleles exist for a single gene within a population, though an individual can only possess two alleles.
- Example: ABO blood group system has three alleles (I^A, I^B, i) with combinations determining blood type.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
