Mendelian Genetics: Pedigrees and Pea Plant Crosses

Vocabulary flashcards covering Mendel's pea plant experiments and pedigree concepts.

Pedigree

A diagram showing how a trait or disorder is inherited across generations, using symbols for sex and shading to indicate affected status.

Autosomal recessive disorder

A genetic condition caused by recessive alleles on an autosome; affected individuals have aa genotype and carriers are typically unaffected (Aa).

aa

Homozygous recessive genotype; expresses the recessive phenotype in autosomal recessive traits.

Aa

Heterozygous genotype; typically a carrier for a recessive trait and usually shows the dominant phenotype.

True breeding (pure line)

A plant that is homozygous for a trait; when self-pollinated, offspring are identical to the parent.

Hybridization

Crossing two true-breeding organisms with different traits to study inheritance.

Cross

The mating of two organisms to produce offspring; in Mendel's work, deliberate mating of different true-breeding lines.

F1 generation

First filial generation; the offspring resulting from a cross between two true-breeding parents.

Dominant trait

An allele or phenotype that is expressed in the heterozygous condition and masks the recessive allele.

Recessive trait

A trait expressed only when two recessive alleles are present (homozygous recessive).

Purple flower

Phenotype used as an example of a dominant trait in Mendel's pea plant crosses.

White flower

Phenotype used as an example of the recessive trait in Mendel's crosses.

Stamen

The male reproductive organ of a flower that produces pollen.

Carpel

The female reproductive organ of a flower that contains ovules and receives pollen.

Pollination

Transfer of pollen from the stamen to the carpel, enabling fertilization.

Character

A heritable feature that can have distinct forms.

Trait

A variant form of a character (e.g., purple vs white).

Distinct, alternative forms

The existence of discrete phenotypes for a trait (e.g., purple or white).

Short generation time

A rapid lifecycle allowing many generations to be studied.

Large number of offspring

A high offspring count per mating enables robust data for inheritance studies.