Dihybrid cross
Encyclopedia
A dihybrid cross is a cross between F1
F1 hybrid
F1 hybrid is a term used in genetics and selective breeding. F1 stands for Filial 1, the first filial generation seeds/plants or animal offspring resulting from a cross mating of distinctly different parental types....

 offspring (first generation offspring) of two individuals that differ in two traits of particular interest. For example: RRyy/rrYY or RRYY/rryy parents result in F1 offspring that are heterozygous for both R and Y (RrYy).

A dihybrid cross is often used to test for dominant and recessive genes
Gênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...

 in two separate characteristics. Such a cross has a variety of uses in Mendelian genetics
Mendelian inheritance
Mendelian inheritance is a scientific description of how hereditary characteristics are passed from parent organisms to their offspring; it underlies much of genetics...

.

Meiosis
Meiosis
Meiosis is a special type of cell division necessary for sexual reproduction. The cells produced by meiosis are gametes or spores. The animals' gametes are called sperm and egg cells....

 (cell reduction) is the cellular process of gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...

 creation. It is where sperm and eggs get the unique set of genetic information that will be used in the development and growth of the offspring of the mating. The rules of meiosis, as they apply to the dihybrid, are codified in Mendel's First Law and Mendel's Second Law, which are also called the Law of Segregation and the Law of Independent Assortment, respectively.

For genes on separate chromosomes, each allele
Allele
An allele is one of two or more forms of a gene or a genetic locus . "Allel" is an abbreviation of allelomorph. Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation...

 pair shows independent segregation. If the first filial generation (F1 generation) produces four offspring, the second filial generation, which occurs by crossing the members of the first filial generation, shows a phenotypic
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...

 (appearance) ratio of 9:3:3:1.

Mendel's Dihybrid Cross

Scientist Gregor Johann Mendel crossed pure breeding peas with round seeds and yellow albumen to pure breeding plants with wrinkled seeds and green albumen. The F1 generation plants all had round seeds and yellow albumen and Mendel predicted that they would be heterozygous for both traits (RrYy).

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