Mendelian Genetics - AP Biology

A variant form of a gene. Different versions of the same gene at a locus.

By crossing with a homozygous recessive individual. If recessive offspring appear, original was heterozygous.

Both alleles are expressed equally. Neither allele is dominant over the other.

$\frac{1}{4}$. From $F1 \times F1$ cross, recessive appears in $\frac{1}{4}$ offspring.

An allele expressed in heterozygotes. Only one copy needed for phenotypic expression.

Offspring from interbreeding F1 individuals. Second generation from F1 × F1 cross.

Genetic makeup of an organism. The actual alleles present in an organism.

Probability of mutually exclusive events is the sum of their probabilities. Add probabilities for either-or scenarios.

They have two dominant alleles for a trait. Expresses dominant phenotype for that trait.

Genes for different traits assort independently. Inheritance of one trait doesn't affect another trait's inheritance.

Dihybrid cross with independent assortment. Classic Mendelian ratio for two independent traits.

A cross examining one trait. Focuses on inheritance patterns of a single characteristic.

Two different alleles for a trait. One allele is different from the other (Aa).

Multiple allelism. More than two allelic variants exist for one gene.

Two identical alleles for a trait. Both alleles are the same (AA or aa).

Pea plants (Pisum sativum). Ideal model organism with clear, distinct traits.

1:2:1 for homozygous dominant, heterozygous, homozygous recessive. Genotype distribution from F1 × F1 monohybrid cross.

An individual heterozygous for a recessive trait. Has recessive allele but doesn't express the trait.

$\frac{3}{4}$. From F1 × F1 cross, dominant appears in $\frac{3}{4}$ offspring.

A cross examining two traits. Studies inheritance of two different characteristics simultaneously.

Both alleles are expressed equally. Neither allele is dominant over the other.

Heterozygote shows an intermediate phenotype. Blended phenotype between two homozygous parents.

3:1 for a single trait with complete dominance. Standard F2 phenotypic ratio from monohybrid cross.

The first filial generation from a cross. Immediate offspring from parental cross.

Predicting the outcome of a genetic cross. Grid showing all possible gamete combinations from a cross.

Probability of two independent events occurring together is the product of their probabilities. Multiply individual probabilities for combined events.

1:2:1 for a single trait with complete dominance. Standard F2 genotypic ratio from monohybrid cross.

Test cross with a heterozygous dihybrid. Equal proportions indicate independent assortment of traits.

Alleles separate during gamete formation. Each parent contributes one allele per trait to offspring.