CH 8 Patterns of inheritance

Genetics

The study of heredity.

Johann Gregor Mendel

The scientist who established the framework for genetics using pea plants.

Continuous variation

Hypothetical process where offspring are considered a mix of parental traits.

Discontinuous variation

Variation observed when individuals show distinctly different traits, such as purple or white flowers.

Hybridization

Mating two self-fertilizing plants with different characteristics.

P generation, F1 generation, F2 generation

Generational terms used in Mendel’s crosses; P is the parental generation, F1 is the first filial generation, and F2 is the second filial generation.

Dominant traits

Traits that are inherited unchanged in hybridization.

Recessive traits

Traits that become latent and only show up in hybrid offspring.

Alleles

Different versions or alternate forms of a gene, classified as dominant or recessive.

Genotype

A person's combination of alleles.

Homozygous dominant

An individual with two dominant alleles (AA).

Heterozygous

An individual with one dominant allele and one recessive allele (Aa).

Homozygous recessive

An individual with two recessive alleles (aa).

Phenotype

A person's outward physical expression of their genotype.

Monohybrid cross

A genetic cross that examines the inheritance of one trait.

Punnett square

A tool used to predict the probability of offspring having a particular trait.

Law of segregation

Mendel's law stating that paired genes must segregate equally into gametes.

Codominant inheritance

Inheritance pattern where both alleles are expressed equally in the phenotype.

Sex-linked inheritance

Inheritance patterns for traits carried on the sex chromosomes, affecting individual probabilities based on sex.

X-linked traits

Traits that are carried on the X chromosome, affecting both males and females.

Y-linked traits

Traits that are carried on the Y chromosome and only affect males.

Polygenic inheritance

Inheritance pattern where multiple genes influence a single trait.

Autosomal dominant disorders

Genetic disorders caused by a dominant gene located on an autosome.

Neurofibromatosis

An autosomal dominant disorder causing benign tumors beneath the skin and bones.

Huntington Disease

An autosomal dominant disorder that causes neurological degeneration.

Autosomal recessive disorders

Genetic disorders caused by recessive genes located on autosomes.

Cystic fibrosis

An autosomal recessive disorder causing thick mucus in lungs and digestive tract.

Tay-Sachs disease

An autosomal recessive disorder leading to neurological impairment.

Phenylketonuria (PKU)

An autosomal recessive disorder affecting the metabolism of phenylalanine.

Duchenne Muscular Dystrophy

A sex-linked disorder causing muscle weakness, primarily affecting males.

Hemophilia A

A sex-linked disorder leading to a lack of a blood clotting factor.

Colorblindness

A sex-linked trait affecting the perception of colors, particularly red-green.

Homozygous dominant

An individual with two identical dominant alleles (AA), resulting in the expression of the dominant trait.