Introduction to Mendelian Genetics

These flashcards cover crucial vocabulary and concepts from Mendelian genetics.

Heredity

The process by which traits are transmitted from parents to offspring.

Dominant Trait

A trait that will appear in the phenotype even if only one allele is present.

Recessive Trait

A trait that only appears in the phenotype when two alleles are present.

True-Breeding

Organisms that, when self-pollinated, produce offspring identical to themselves.

Hybrid

The offspring of two different true-breeding varieties.

Monohybrid Cross

A cross that examines the inheritance of only one specific trait.

F1 Generation

First filial generation; the offspring of the parental generation.

F2 Generation

Second filial generation; produced from the self-fertilization of F1 plants.

Punnett Square

A diagram used to predict the genotype and phenotype combinations in genetic crosses.

Allele

An alternative form of a gene.

Homozygous

Having two identical alleles for a given gene.

Heterozygous

Having two different alleles for a given gene.

Genotype

The genetic makeup of an organism, including all alleles.

Phenotype

The observable physical characteristics of an organism.

Principle of Segregation

The two alleles for a gene segregate during gamete formation.

Independent Assortment

The principle that alleles for different traits are distributed to gametes independently.

Dihybrid Cross

A cross examining two traits simultaneously.

Polygenic Inheritance

A trait that is controlled by multiple genes.

Pleiotropy

A single gene that affects multiple traits.

Multiple Alleles

More than two possible alleles exist for a gene in a population.

Codominance

A situation in which both alleles contribute to the phenotype.

Incomplete Dominance

A situation in which a heterozygote expresses an intermediate phenotype.

Environmental Influence

Factors from the environment that can affect the expression of traits.

Epistasis

Interaction of different genes that affects the expression of a phenotype.

Barr Body

The inactivated X chromosome in a female's cells.

Mosaicism

Presence of two or more genetically different cell lines in the same individual.