Biology Module 10: Evolution and Patterns of Inheritance Part 1

Vocabulary flashcards covering Mendelian genetics, inheritance patterns, and fundamental terminology from Biology 110 Module 10.

Alleles

Different forms of a gene for a specific trait, which are found at the same location on a chromosome.

Locus

The specific location on a chromosome where alleles for a particular gene are found.

Homologous Chromosomes

Pairs of chromosomes, one inherited from each parent, that are the same length, have the same centromere location, and carry similar types of genes.

Blending Concept of Inheritance

A belief held by breeders prior to Mendel that thought offspring appearance was an intermediate combination of both parents' appearances, such as red and white flowers producing pink flowers.

Pisum sativum

The scientific name for the garden peas used by Gregor Mendel in his heredity experiments.

True-breeding

Varieties of plants that, through self-pollination, produce offspring with the same traits as the parent.

Law of Segregation

Mendel's law stating that each individual has two factors for each trait, which separate during gamete formation so that each gamete contains only one factor from each pair.

Phenotype

The observable characteristics of an organism, which can be physical, microscopic, or metabolic (enzymatic).

Genotype

The specific alleles or version of a gene carried by the chromosomes that are responsible for a trait, usually represented by letters.

Homozygous

A genotype in which an individual has two of the same alleles for a particular trait.

Heterozygous

A genotype in which an individual has two different alleles for a particular trait.

Dominant Allele

An allele represented by a capital letter that codes for the trait that is expressed in a heterozygous individual.

Recessive Allele

An allele represented by a lowercase letter whose trait is only expressed when the genotype is homozygous recessive.

Punnett Square

A useful tool used to solve genetics problems and determine the potential genotypes and phenotypes of offspring.

Genotypic Ratio

The proportional representation of offspring genotypes, expressed as \text{# Homozygous Dominant : # Heterozygous : # Homozygous Recessive}.

Phenotypic Ratio

The proportional representation of offspring observable traits, expressed as \text{# Dominant Trait : # Recessive Trait}.

Product Rule of Probability

States that the chance of two or more independent events occurring together is the product of their separate chances, calculated using multiplication.

Sum Rule of Probability

States that the chance of an event that can occur in more than one way is the addition of the individual chances.

Testcross

An experiment where an organism with a dominant phenotype is crossed with a homozygous recessive individual to determine if the dominant parent is homozygous or heterozygous.

Law of Independent Assortment

Mendel's law stating that each pair of factors (homologous chromosomes) separates independently of other pairs, and all possible combinations of factors can occur in the gametes.

Dihybrid Cross

A two-trait cross between individuals who are heterozygous for both traits, which results in an expected phenotypic ratio of $9:3:3:1$.

Biological Evolution

A process of change in living organisms over time, which Darwin's theory of natural selection explains through observations and patterns of inheritance.