Monohybrid and Dihybrid Crosses in Genetics

A comprehensive set of flashcards covering key vocabulary and concepts related to Mendelian genetics, monohybrid and dihybrid crosses, and the principles of heredity.

Monohybrid Cross

A genetic cross involving two parents that are heterozygous for one trait.

Principle of Segregation

Mendel's first law stating that alleles segregate randomly into gametes.

Alleles

Different forms of a gene that determine a specific trait.

Punnett Square

A diagram used to predict the genotypes of offspring from parental genotypes.

F1 Generation

The first filial generation obtained from the cross of two parental genotypes.

Gametes

Reproductive cells that carry one allele for each gene.

Phenotype

The observable physical or biochemical characteristics of an organism.

Genotype

The genetic constitution of an individual organism.

Homozygous

An organism that carries two identical alleles for a given gene.

Heterozygous

An organism that carries two different alleles for a given gene.

Dominant Allele

An allele that is expressed in the phenotype even when heterozygous.

Recessive Allele

An allele that is only expressed in the phenotype when homozygous.

Test Cross

A cross between an individual with an unknown genotype and a homozygous recessive individual.

Dihybrid Cross

A genetic cross involving two traits, each controlled by different genes.

Independent Assortment

Mendel's second law stating that genes for different traits assort independently.

Phenotypic Ratio

The ratio of different phenotypes produced in a genetic cross.

Genotypic Ratio

The ratio of different genotypes produced in a genetic cross.

Thomas Hunt Morgan

A scientist known for his work with fruit flies and the chromosomal theory of inheritance.

Drosophila melanogaster

The scientific name for the common fruit fly, often used as a model organism in genetics.

Pure Breeding

Organisms that produce offspring identical to themselves when self-fertilized.

Meiosis

A type of cell division that reduces the chromosome number by half.

Homologous Chromosomes

Chromosomes that are similar in shape, size, and genetic content.

Gamete Formation

The process by which diploid cells divide and produce haploid gametes.

Allelic Combinations

Different combinations of alleles that can result from a genetic cross.

E phenotype

The phenotype associated with the ebony color in fruit flies.

Wild type

The most common phenotype found in a natural population.

Cystic Fibrosis

A hereditary disorder affecting the lungs and digestive system caused by a genetic mutation.

Independent Events

Events where the outcome of one does not affect the outcome of another.

Product Rule

A rule used in genetics to determine the probability of two independent events occurring.

Sum Rule

A rule used in genetics to predict the probability of mutually exclusive events happening.

Chromosome Theory of Inheritance

The theory that genes are located on chromosomes and that chromosomes are the carriers of genetic material.

Allelic Frequency

The relative frequency of an allele at a genetic locus in a population.

Genetic Cross

The mating of two organisms to analyze the inheritance of specific traits.

1:2:1 Ratio

A typical genotypic ratio observed in a monohybrid cross.

3:1 Ratio

A common phenotypic ratio observed in a monohybrid cross involving one dominant and one recessive trait.

9:3:3:1 Ratio

The typical phenotypic ratio observed in a dihybrid cross.

Offspring

The resultant progeny from a genetic cross between parents.

Mendel's Laws of Heredity

The principles governing the inheritance of traits based on Gregor Mendel's experiments.

Genetic Variability

The tendency of individual genetic characteristics in a population to differ.

Anaphase I

The stage in meiosis where homologous chromosomes are pulled apart to opposite sides of the cell.

Telophase I

The stage in meiosis where the cell splits into two after chromosome segregation.

Interphase

The phase of the cell cycle where the cell prepares for division.

Prophase I

The first stage of meiosis where homologous chromosomes pair up.

Metaphase I

The phase of meiosis where homologous chromosome pairs align at the cell's equatorial plane.

Metaphase II

The phase of meiosis where chromosomes line up individually on the metaphase plate.

Reproductive Strategy

The method by which organisms ensure offspring production.

Hypothesis Testing

The process of making inferences regarding a population based on a sample.

Allele Frequency Calculation

A method used to determine the prevalence of an allele in a population based on genetic crosses.

Hereditary Variations

Differences in traits passed from parents to offspring.