Patterns of Inheritance

dihybrid cross

Dihybrid cross is a cross between individuals that have different alleles for the same gene

genotype

A genotype is an individual's collection of genes. The term also can refer to the two alleles inherited for a particular gene. The genotype is expressed when the information encoded in the genes' DNA is used to make protein and RNA molecules. The expression of the genotype contributes to the individual's observable traits, called the phenotype.

monohybrid cross

A monohybrid cross is a crossbreeding experiment that follows the inheritance of a single characteristic across one or more generations.

phenotype

A phenotype is an individual's observable traits, such as height, eye color, and blood type. The genetic contribution to the phenotype is called the genotype. Some traits are largely determined by the genotype, while other traits are largely determined by environmental factors.

Trait

A trait is a specific characteristic of an organism. Traits can be determined by genes or the environment, or more commonly by interactions between them. The genetic contribution to a trait is called the genotype. The outward expression of the genotype is called the phenotype.

allele

An allele is one of two or more versions of a gene. An individual inherits two alleles for each gene, one from each parent. If the two alleles are the same, the individual is homozygous for that gene. If the alleles are different, the individual is heterozygous. Though the term "allele" was originally used to describe variation among genes, it now also refers to variation among non-coding DNA sequences.

codominance

Codominance is a relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele usually will be expressed, while the effect of the other allele, called recessive, is masked. In codominance, however, neither allele is recessive and the phenotypes of both alleles are expressed.

cross-fertilization

Cross-fertilization is fertilization by the union of male and female gametes from different individuals of the same species.

dominant

Dominant refers to the relationship between two versions of a gene. Individuals receive two versions of each gene, known as alleles, from each parent. If the alleles of a gene are different, one allele will be expressed; it is the dominant gene. The effect of the other allele, called recessive, is masked.

genetic linkage

Genetic linkage is that certain genes tend to be inherited together, because they are on the same chromosome. Thus parental combinations of characters are found more frequently in offspring than nonparental

Genetics

Genetics is the study of the patterns of inheritance of specific traits. Relating to genes and genetic information. Also known as heredity. Modern theories explain how traits are passed down from parent to offspring.

heterozygous

Heterozygous refers to having inherited different forms of a particular gene from each parent. A heterozygous genotype stands in contrast to a homozygous genotype, where an individual inherits identical forms of a particular gene from each parent.

homozygous

Homozygous is a genetic condition where an individual inherits the same alleles for a particular gene from both parents.

hybrid

Hybrid is sn offspring resulting from the cross between parents of different species or sub-species

intermediate inheritance

Intermediate inheritance is the acquisition of characters or qualities by transmission from parent to offspring.

polygenic inheritance

Polygenic inheritence is a non-Mendelian form of inheritance in which a particular trait is produced by the interaction of many genes

Punnett square

Punnett square is a tool that helps to show all possible allelic combinations of gametes in a cross of parents with known genotypes in order to predict the probability of their offspring possessing certain sets of alleles.

recessive

Recessive is a quality found in the relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, the dominant allele will be expressed, while the effect of the other allele, called recessive, is masked. In the case of a recessive genetic disorder, an individual must inherit two copies of the mutated allele in order for the disease to be present.

sex-linked gene

Sex-linked gene is pertaining to a gene located in the sex chromosome

testcross

Test cross is crossing of an unknown genotype to a recessive homozygote so that the phenotype of the progeny corresponds directly to the chromosomes carried by the parents of unknown genotype

chromosome theory of inheritance

The chromosome theory of inheritance is the theory that chromosomes are linear sequences of genes. The unifying theory stating that inheritance patterns may be generally explained by assuming that genes are located in specific sites on chromosomes.

gene locus

The location of a gene (or of a significant sequence) on a chromosome or on a linkage map.