Key difference - monohybrid cross vs. dihybrid cross
Monohybrid crossing and dihybrid crossing are two genetic crossing methods that are used to study the inheritance of allele pairs . These are useful for understanding how traits are inherited from one generation to another. Monohybrid cross is a genetic cross that contains a single pair of genes that are responsible for a trait. In a monohybrid cross, the parents differ in a single trait. Dihybrid cross is a genetic cross that involves two pairs of genes that are responsible for two traits. In a dihybrid cross, the parents have two different independent traits. The main difference between monohybrid crosses and dihybrid crosses is that in a monohybrid cross the inheritance of a trait (e.g. height) is examined, while in a dihybrid cross the inheritance of two independent characteristics (e.g. flower color, stem length) is examined. is being investigated.
Key areas covered
1. What is a monohybrid cross - definition, characteristics, process 2. What is a dihybrid cross - definition, characteristics, process 3. What are the similarities between monohybrid cross and dihybrid cross - outline of the common characteristics 4. What is the difference between monohybrid cross and dihybrid cross - comparison of the most important differences
Key Terms: Allele, Dihybrid Cross, Genetic Cross, Inheritance, Monohybrid Cross, Single Trait Cross, Traits, Two Traits Cross
What is a monohybrid cross?
A monohybrid cross is a genetic cross that occurs between two individuals and focuses on the inheritance of one trait at the same time. Monohybrid cross is also known as a single trait cross . Two homozygous parents are selected for this cross and studies are conducted on only one trait (e.g. flower color), ignoring all other traits; thus only a single gene pair is involved in this test method. This method is a cross between two real breeding parent lines. The following picture explains the process of monohybrid crossing.
One parent is homozygous for the dominant allele and the other parent is homozygous for the recessive allele . The offspring are predicted and assessed for trait inheritance in monohybrid crosses. Therefore, the phenotypic ratio of the resulting offspring in the monohybrid cross is 3: 1.
What is a dihybrid cross?
A dihybrid cross is a genetic cross that occurs between two individuals and focuses on the inheritance of two independent traits at the same time. Dihybrid cross is also known as a two- trait cross. The two parents considered for this cross have two independent traits (e.g. pod color and pod shape in pea plants). Thus, a dihybrid cross comprises two pairs of genes. The following figure explains the process of dihybrid crossing.
In a dihybrid cross, the traits are considered unrelated and have an equal chance of dividing on offspring. Each pair of alleles segregates independently from the gametes . The progeny is predicted and scored for inheritance of two traits. The phenotypic ratio of the offspring generation is 9: 3: 3: 1 in a dihybrid cross.
Similarities Between Monohybrid Cross and Dihybrid Cross
- Genes are involved in both monohybrid cross and dihybrid cross.
- Both crosses examine how traits are transmitted to the offspring.
- In either crossbreed, genetic alleles are not considered connected.
Difference between monohybrid cross and dihybrid cross
Monohybrid Cross: A monohybrid cross is a genetic cross between homozygous individuals with different alleles for a single gene locus of interest.
Dihybrid cross: A dihybrid cross is a genetic cross between individuals with different alleles for two gene loci of interest.
Number of characteristics taken into account
Monohybrid Cross: In a monohybrid cross, a character is viewed and examined.
Dihybrid cross: In a dihybrid cross, two independent characters are considered and examined.
Number of gene pairs
Monohybrid cross: A monohybrid cross involves a single pair of genes.
Dihybrid cross: Two pairs of genes are involved in a dihybrid cross.
Phenotypic ratio of the offspring
Monohybrid Cross: The predicted phenotypic ratio of a monohybrid cross is 3: 1.
Dihybrid Cross: The predicted phenotypic ratio of the dihybrid cross is 9: 3: 3: 31.
Monohybrid Cross: Monohybrid Cross is important to determine the dominance relationship of the alleles.
Dihybrid Cross: Dihybrid Cross is important in assessing the independent range of alleles.
The main difference between monohybrid and dihybrid cross is the number of traits that are examined in offspring. In the case of a monohybrid cross, the inheritance of a single trait is predicted. Parents of monohybrid crosses differ in one trait and are homozygous for that trait. In dihybrid crosses, two traits are predicted to inherit. Parents of the dihybrid cross differ in two features. When the alleles or genes are not linked, the resulting phenotypic ratio for a monohybrid cross is 3: 1, while for a dihybrid cross it is 9: 3: 3: 1.
1. “Monohybrid Cross.” Wikipedia, Wikimedia Foundation, January 8, 2018, available here . "Dihybrid Cross." Wikipedia, Wikimedia Foundation, October 22, 2017, available here. 3. Bailey, Regina. "Monohybrid Cross: A Breeding Experiment." ThoughtCo, available here .