Applying Mendel's Principles

This set of flashcards covers key vocabulary and concepts from Mendelian genetics, including definitions of terms related to inheritance, genotype and phenotype distinctions, and the use of Punnett squares.

Mendel's Principles

Fundamental concepts that describe how traits are inherited through units called genes.

Alleles

Different forms of a gene that may exist for a particular trait.

Dominant Allele

An allele that masks the effect of a recessive allele, typically represented by a capital letter (A).

Recessive Allele

An allele whose effects are masked by a dominant allele, typically represented by a lowercase letter (a).

Segregation

The separation of alleles during gamete formation, ensuring each gamete carries only one allele for each gene.

Independent Assortment

The principle that alleles for different traits segregate independently of one another during gamete formation.

Genotype

The genetic makeup of an organism (e.g., AA, Aa, or aa).

Phenotype

The physical traits or observable characteristics of an organism (e.g., purple flowers).

Punnett Square

A graphical tool used to predict the possible genotypes and phenotypes of offspring from parent genotypes.

Homozygous

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

Heterozygous

Having two different alleles for a particular gene (Aa).

Probability

The likelihood that a particular event will occur, often used to predict genetic outcomes (e.g., 50\% or \frac{1}{2}).

P Generation

The parental generation; the original pair of organisms used in a genetic cross.

F1 Generation

The first filial generation; the offspring resulting from a cross between the P generation parents.

F2 Generation

The second filial generation; the offspring resulting from the crossing or self-pollination of F1 individuals.

Gene

A sequence of DNA that codes for a protein and determines a specific trait.

Trait

A specific characteristic of an individual, such as seed color or plant height.

Hybrid

The offspring of parents with different traits or different genetic backgrounds.

Monohybrid Cross

A genetic cross that tracks the inheritance of a single trait.

Dihybrid Cross

A genetic cross that tracks the inheritance of two different traits simultaneously.

Incomplete Dominance

A inheritance pattern where one allele is not completely dominant over another, resulting in an intermediate phenotype (e.g., red + white = pink).

Codominance

A situation where the phenotypes produced by both alleles are clearly and separately expressed (e.g., speckled chicken feathers).

Multiple Alleles

A gene that exists in more than two allelic forms within a population (e.g., ABO blood types).

Polygenic Traits

Traits controlled by the interaction of two or more genes, often resulting in a wide range of phenotypes (e.g., human skin color).

Genetics

The scientific study of heredity and the variation of inherited characteristics.

Fertilization

The process in sexual reproduction in which male and female reproductive cells join to form a new cell (zygote).

Gametes

Specialized haploid cells used in sexual reproduction, such as sperm and egg cells, that carry genetic information.

Principle of Dominance

Mendel's conclusion that some alleles are dominant and will mask the expression of recessive alleles when present together.

True-breeding

Organisms that, when allowed to self-pollinate, produce offspring identical to themselves for a specific trait over many generations.

Self-pollination

The process where pollen from the male organs of a plant fertilizes the female organs of the same plant or flower.

Cross-pollination

A technique where pollen from one plant is used to fertilize a different plant, allowing for the study of trait inheritance from parents with different characteristics.

Genome

The complete set of genetic instructions and material found within an organism.

Meiosis

A specialized type of cell division that reduces the chromosome number by half, creating four genetically distinct haploid cells.

Homologous Chromosomes

Pairs of chromosomes (one from each parent) that are similar in size, shape, and gene content.

Crossing-over

The process during Prophase I of meiosis where homologous chromosomes exchange segments of DNA, resulting in new genetic combinations.