Mendelian Genetics - Vocabulary

Vocabulary flashcards covering key Mendelian genetics concepts from the notes.

Diploid

An organism with two sets of chromosomes; carries two alleles for each gene, which separate during gamete formation.

Haploid

A cell with a single set of chromosomes; in gametes there is one allele per gene.

Gamete

A haploid reproductive cell (sperm or egg) that carries one allele per gene.

Allele

Alternative form of a gene at a given locus; often denoted by different letters (e.g., A and a).

Dominant allele

An allele that determines the phenotype in a heterozygote and masks the recessive allele.

Recessive allele

An allele whose phenotype is expressed only when paired with another recessive allele (in homozygotes or when both alleles are recessive).

Homozygous

Having two identical alleles for a gene (AA or aa).

Heterozygous

Having two different alleles for a gene (Aa).

Genotype

The genetic makeup for a gene; the pair of alleles an organism carries.

Phenotype

The observable traits or characteristics; the outward expression of the genotype.

Trait (character)

A distinct variant of a character (e.g., red vs white flower color); Mendel used 'character' where we say 'trait'.

Environment interaction

Traits can be determined by alleles, the environment, or interactions between them.

P generation (Parental cross)

The initial cross in Mendel's experiments; the parental generation.

F1 generation

First filial generation; offspring of the P cross.

F2 generation

Second filial generation; offspring produced by crossing F1 individuals.

Monohybrid cross

A cross examining the inheritance of a single trait.

Dihybrid cross

A cross examining two different traits (e.g., A/a and B/b) simultaneously.

True-breeding

Lines that, when selfed or crossed, produce offspring with the same phenotype generation after generation.

Testcross

Crossing an individual with a homozygous recessive to reveal the genotype of the dominant phenotype.

Segregation

Mendel's first law: alleles segregate into gametes, so each gamete carries one allele per gene.

Zygote

A diploid cell formed when two gametes fuse; contains two alleles for each gene.

Genetics

The science of heredity and variation in living organisms.

Probability in genetics

The use of probability to predict offspring genotypes/phenotypes (e.g., Mendel’s 3:1 ratios).