Key Concepts in Genetics

Allele

A variant form of a gene found at a specific location on a chromosome that can influence traits.

Chromosome Theory of Inheritance

A theory that explains how genes are inherited through chromosomes from parents to offspring.

Codominance

A genetic scenario where both alleles in a heterozygous individual are fully expressed, resulting in a phenotype that shows both traits.

Complete Dominance

A situation where one allele completely masks the effect of another allele at the same gene locus in a heterozygous individual.

Cross-fertilization

The process of fertilizing an ovule with pollen from a different flower, enhancing genetic diversity.

Dihybrid

An organism that has two different alleles for two traits.

Dihybrid Cross

A genetic cross that examines the inheritance patterns of two different traits at the same time.

Dominant

An allele that expresses its trait in the phenotype even when only one copy is present.

Gene Locus

The specific location of a gene on a chromosome.

Gene Map

A representation that shows the arrangement and relative positions of genes on a chromosome.

Genetic Linkage

The tendency of genes located close to each other on a chromosome to be inherited together during meiosis.

Genotype

The genetic makeup of an individual, including all the alleles present for a particular trait.

Hereditary

Referring to traits or characteristics that are passed down from parents to offspring through genes.

Heritable

Describing traits that can be transmitted from one generation to the next through genetic inheritance.

Heterozygous

An organism that has two different alleles for a specific gene.

Homozygous

An organism that has two identical alleles for a specific gene.

Hybrid

An offspring resulting from the crossbreeding of two different species or varieties.

Incomplete Dominance

A genetic situation where neither allele is completely dominant, resulting in a blended phenotype in heterozygous individuals.

Inheritance Patterns

The predictable ways in which traits are passed from parents to offspring based on genetic principles.

Law of Independent Assortment

A principle stating that the alleles for different traits segregate independently during the formation of gametes.

Law of Segregation

A principle that states that during the formation of gametes, the two alleles for a trait separate so that each gamete carries only one allele for each gene.

Monohybrid

An organism that has two different alleles for one trait being studied.

Phenotype

The observable characteristics or traits of an organism, resulting from the interaction of its genotype with the environment.

Probability

The likelihood or chance of a particular genetic outcome occurring in offspring.

Punnett Square

A diagram used to predict the genetic combinations resulting from a cross between two individuals.

Recessive

An allele that does not manifest in the phenotype unless two copies are present.

Sex-linked Gene

A gene located on a sex chromosome, which often leads to traits that are expressed differently in males and females.

Test Cross

A breeding experiment used to determine the genotype of an individual exhibiting a dominant trait by crossing it with a homozygous recessive individual.