Chapter 1-7 Genetics Introduction (Probability Rules & Mendelian Inheritance)

Vocabulary flashcards covering probability rules, genotype/phenotype concepts, Mendel's crosses, and foundational genetic laws.

Multiplication Rule

Used when two independent events must both occur; multiply their probabilities.

Addition Rule

Used when either of multiple mutually exclusive outcomes is desired; add their probabilities.

Genotype

The genetic makeup of an organism; the specific alleles it carries (e.g., PP, Pp, pp).

Phenotype

The observable trait produced by genotype (and environment).

Dominant allele

An allele whose trait is expressed in a heterozygote; masks the recessive allele.

Recessive allele

An allele whose trait is expressed only when homozygous recessive.

Heterozygous

Two different alleles at a gene locus (e.g., Pp).

Homozygous dominant

Two copies of the dominant allele (e.g., PP).

Homozygous recessive

Two copies of the recessive allele (e.g., pp).

Punnett square

A diagram used to predict offspring genotypes and probabilities from parental alleles.

Pure-breeding

Homozygous lines used for breeding to maintain a trait across generations.

F1 generation

First filial generation; offspring of pure-breeding parents; often uniform for a trait.

F2 generation

Offspring of crossing F1 individuals; shows segregation and variation.

Law of Segregation

Alleles separate during gamete formation; offspring inherit one allele from each parent.

Law of Independent Assortment

Alleles of different genes assort independently during gamete formation if on different chromosomes.

Particulate inheritance

Heredity is based on discrete units (alleles) that do not blend.

Blending inheritance

Old idea that parental traits blend in offspring; Mendel showed this is not the case.

Dominant phenotype

Phenotype expressed when at least one dominant allele is present (PP or Pp).

Recessive phenotype

Phenotype expressed only when both alleles are recessive (pp).