Genetics and Punnett Squares: Key Vocabulary

These flashcards cover key vocabulary and concepts from genetics and Punnett squares.

True Breeding

Parents that are homozygous for a single trait, consistently producing offspring with that trait.

Homozygous

An organism that has two identical alleles for a trait (e.g., RR or rr).

Filial Generation (F1)

First generation of offspring from a parental cross.

Filial Generation (F2)

Second generation of offspring from a cross of the F1 generation.

Meiosis

A type of cell division that results in four haploid gametes, each with half the number of chromosomes of the original cell.

Punnett Square

A chart used to predict the genotypes of a genetic cross.

Phenotype

The observable traits of an organism determined by its genotype.

Genotype

The genetic makeup of an organism, often represented by letters (e.g., RR, Rr, rr).

Allele

Different forms of a gene that can exist at a single locus.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis.

Law of Segregation

The principle that each gamete carries only one allele for each gene due to the separation of homologous chromosomes.

Law of Independent Assortment

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

Autosomal Recessive

A pattern of inheritance in which two copies of a mutated gene must be present for the disorder to manifest.

Autosomal Dominant

A pattern of inheritance where only one copy of a mutated gene is sufficient to cause the disorder.

X-linked Trait

A gene located on the X chromosome, where males are more likely to express the trait.

Locus

The specific location of a gene on a chromosome.

Cystic Fibrosis (CF)

An autosomal recessive disorder affecting the respiratory and digestive systems, caused by mutations in the CFTR gene.

Gamete

A haploid cell that is used in sexual reproduction, e.g., sperm or egg.

Zygote

The fertilized egg formed from the fusion of two gametes.

Sister Chromatids

Identical copies of a chromosome that are connected by a centromere.

Non-Sister Chromatids

Chromatids from homologous chromosomes that are not identical.

Carrier

An individual who carries one copy of a recessive allele for a trait but does not exhibit the trait.

Phenotypic Ratio

The ratio of different phenotypes in the offspring from a genetic cross.

Genotypic Ratio

The ratio of different genotypes in the offspring from a genetic cross.

Recombinant Chromosomes

Chromosomes that carry new combinations of alleles due to crossing over.

Mendelian Genetics

The study of how traits are inherited through the interactions of alleles.

Dominant Allele

An allele that expresses its phenotype even in the presence of a recessive allele.

Recessive Allele

An allele that only expresses its phenotype when two copies are present.

Respiratory and Digestive Systems

Body systems most commonly affected by cystic fibrosis.

Chromosome

A thread-like structure made of DNA that contains genes.

Mutation

A change in the DNA sequence that can lead to genetic disorders.

Nucleotide

The basic building block of DNA and RNA, consisting of a base, sugar, and phosphate group.

Intergenerational Probability

The likelihood of inheriting traits or diseases across generations.