Chapter 15 Parents to Offspring I- Patterns that follow Mendel's laws

Mendel’s Laws of Inheritance

Principles that describe how traits are inherited from one generation to the next.

Chromosome Theory of Inheritance

Theory stating that genes are located on chromosomes and are passed to offspring through cell division.

Pedigree Analysis

A genetic tool used to trace inheritance patterns in humans through family trees.

Particulate Inheritance

The theory that traits are inherited as discrete units, now known as genes.

Dominant Trait

A trait that is expressed in the phenotype even if only one allele is present.

Recessive Trait

A trait that is only expressed in the phenotype when two copies of the allele are present.

Genotype

The genetic composition of an individual, often represented by letters.

Phenotype

The observable characteristics or traits of an individual resulting from gene expression.

Gamete

A haploid reproductive cell that can unite with another to form a zygote.

Punnett Square

A grid used to predict the outcome of genetic crosses by showing possible allele combinations.

Monohybrid Cross

A genetic cross focusing on one trait with two alleles.

Dihybrid Cross

A genetic cross examining two traits simultaneously, each with two alleles.

Law of Segregation

Mendel's law stating that alleles separate during gamete formation.

Law of Independent Assortment

Mendel's law that states that the alleles of different genes assort independently of one another during gamete formation.

True-Breeding Line

A line of plants that continues to exhibit the same trait after several generations of self-fertilization.

Hybridization

The process of breeding two individuals with different characteristics.

Homozygous Dominant

An individual with two dominant alleles for a particular gene (e.g., TT).

Heterozygous

An individual with one dominant and one recessive allele for a particular gene (e.g., Tt).

Homozygous Recessive

An individual with two recessive alleles for a particular gene (e.g., tt).

Trait

An identifiable characteristic of an organism, often referring to a variant.

Pleiotropy

The phenomenon where a single gene influences multiple phenotypic traits.

Incomplete Dominance

A pattern of inheritance where heterozygotes display an intermediate phenotype.

Norm of Reaction

The range of phenotypes that a single genotype can produce under different environmental conditions.

X-linked Inheritance

A pattern of inheritance that involves genes located on the X chromosome.

Autosomal Recessive Disorder

A genetic condition that manifests only in individuals who inherit two recessive alleles.

Autosomal Dominant Disorder

A genetic condition that can manifest in individuals with just one dominant allele.

Diploid Cell

A cell that contains two complete sets of chromosomes, one from each parent.

Haploid Cell

A cell that contains one complete set of chromosomes.

Wild-type Allele

The most common allele in a population, typically associated with the normal phenotype.

Mutant Allele

An allele that has undergone a mutation and typically is less common.

Environmental Influence

The effect that environmental factors have on the expression of traits.

Cystic Fibrosis

An autosomal recessive disorder characterized by thick mucus in the lungs.

Huntington Disease

An autosomal dominant disorder that affects the brain and nervous system.

Gene

A unit of heredity that contributes to the characteristics or traits of an organism.

Allele

Different versions of a gene that can exist at a specific locus.

Chromosome

Structures within cells that contain DNA and genetic information.