AP Biology non-Mendelian inheritance review

What is non-Mendelian inheritance?

Patterns of inheritance that do not follow Mendel's laws, including incomplete dominance, codominance, and multiple alleles.

Define incomplete dominance.

A form of inheritance where the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes.

True or false: Codominance shows both dominant traits at once.

True, because both alleles in a heterozygote are fully expressed.

Difference between codominance and incomplete dominance.

Codominance: both traits expressed equally (e.g., AB blood type). Incomplete dominance: mixed phenotype (e.g., red + white = pink flowers).

Fill in the blank: A trait influenced by multiple genes is called ___.

polygenic.

What does epistasis mean?

A situation where one gene affects the expression of another gene, often masking its effect.

True or false: Multiple alleles refer to more than two alleles for a gene.

True, because multiple alleles exist for some genes, like ABO blood types.

Define pleiotropy.

A single gene influencing multiple phenotypic traits or characteristics.

What is the significance of sex-linked traits?

Traits associated with genes located on sex chromosomes, often showing different patterns of inheritance in males and females.

What is a common example of a polygenic trait?

Human skin color, influenced by multiple genes leading to a continuous range of phenotypes.

Difference between dominant and recessive alleles.

Dominant alleles mask the effect of recessive alleles in heterozygotes, while recessive alleles only manifest in homozygotes.

True or false: Environmental factors can influence gene expression.

True, because external conditions can affect phenotypes through gene-environment interactions.

What is an example of a trait showing codominance?

ABO blood groups, where both A and B alleles are expressed in type AB individuals.

Fill in the blank: Traits that are expressed differently in males and females are called ___.

sex-linked traits.

What is the role of the environment in polygenic traits?

Environmental factors can modify phenotypes, leading to variation even among genetically similar individuals.

Define linked genes.

Genes located close to each other on the same chromosome, often inherited together due to reduced recombination.

True or false: All mutations are harmful.

False, because some mutations can be neutral or beneficial, affecting evolution.

What is the purpose of a test cross?

To determine the genotype of an individual with a dominant phenotype by crossing it with a homozygous recessive.

Difference between autosomal and sex-linked inheritance.

Autosomal inheritance involves non-sex chromosomes, while sex-linked inheritance involves genes on sex chromosomes.

What does the term ‘phenotypic ratio’ refer to?

The ratio of different phenotypes that appear in offspring, reflecting inheritance patterns.

Define aneuploidy.

An abnormal number of chromosomes, such as trisomy or monosomy, which can lead to genetic disorders.