Extensions of Mendelian Genetics

These flashcards cover key concepts from Mendelian and non-Mendelian genetics, including genetic inheritance patterns, types of alleles, and specific inheritance mechanisms.

Mendelian inheritance

Inheritance patterns that obey Mendel's two laws: law of segregation and law of independent assortment.

Dominant allele

An allele that expresses its trait in a homozygous or heterozygous state.

Recessive allele

An allele that does not affect the phenotype in a heterozygote.

Wild type allele

The most common allele(s) in a population associated with the 'normal' phenotype.

Mutant allele

Alleles that arise from random mutations in existing alleles, often associated with less common traits.

Incomplete dominance

A genetic scenario where the heterozygote expresses an intermediate phenotype.

Codominance

A condition in which both alleles in a heterozygote are fully expressed, resulting in a phenotype that shows both traits.

Multiple alleles

More than two alleles that can control a trait within a population, such as the ABO blood group.

Overdominance

When heterozygotes have a selective advantage over either homozygote.

Sex-linked inheritance

Inheritance patterns associated with genes on sex chromosomes, often affecting males and females differently.

Hemizygous

Having only one allele for a gene, as in males with respect to genes on the X chromosome.

Reciprocal cross

Crosses that switch which parent carries the trait to determine if the trait is sex-linked.

Sex-influenced inheritance

A trait that is dominant in one sex but recessive in another.

Sex-limited inheritance

Traits that are expressed in only one sex, controlled by sex hormones.

Recessive lethal allele

An allele that can cause death if present in two copies.

Epistasis

An interaction where one gene masks the expression of another gene.

Gene interactions

Situations where two or more different genes influence the expression of a single trait.

Complementation

Production of wild-type offspring phenotypes by parents with similar recessive phenotypes.

Maternal effects

When the genotype of the mother determines the phenotype of the offspring.

Extranuclear inheritance

Inheritance of traits determined by organelles, such as mitochondria, inherited from the mother.