Extensions of Mendelian Inheritance Flashcards

These flashcards cover extensions of Mendelian inheritance, including incomplete dominance, overdominance, codominance, lethal alleles and sex-linked traits.

What is incomplete dominance?

A pattern where the heterozygote exhibits a phenotype that is intermediate between the corresponding homozygotes.

What is overdominance?

A phenomenon in which a heterozygote is more vigorous than both of the corresponding homozygotes; also known as heterozygote advantage.

What is codominance?

A pattern where the heterozygote expresses both alleles simultaneously without forming an intermediate phenotype.

What are wild-type alleles?

Prevalent alleles in a population that typically encode proteins that function normally and are made in the proper amounts.

What are mutant alleles?

Alleles that have been altered by mutation, often defective in their ability to express a functional protein and are often inherited in a recessive fashion.

What is incomplete penetrance?

A dominant allele does not always influence the outcome of a trait in a heterozygote individual.

What is expressivity?

The degree to which a trait is expressed.

What is a lethal allele?

An allele that has the potential to cause the death of an organism, typically due to mutations in essential genes.

What is pleiotropy?

Multiple effects of a single gene on the phenotype of an organism.

What is epistasis?

An inheritance pattern in which the alleles of one gene mask the phenotypic effects of the alleles of a different gene.

What is a gene modifier effect?

A phenomenon in which an allele of one gene modifies the phenotypic outcome of the alleles of a different gene.

What is gene redundancy?

A pattern in which the loss of function in a single gene has no phenotypic effect, but the loss of function of two genes has an effect.

What is Sex-Influenced Inheritance?

Traits where an allele is dominant in one sex but recessive in the opposite sex. Sex influence is a phenomenon of heterozygotes and are autosomal.

What is Sex-limited Inheritance?

Traits that occur in only one of the two sexes Genes are controlled by sex hormones or the sexual development pathway

What is genetic polymorphism?

Genetic Polymorphism can produce more than one wild- type in large populations