A monohybrid cross is a breeding experiment between two organisms that are both heterozygous for one specific trait. Essentially, it's used to study how one gene is inherited. According to provided information, "A monohybrid cross is the hybrid of two individuals with homozygous genotypes which result in the opposite phenotype for a certain genetic trait," and it "is responsible for the inheritance of one gene."
Understanding Monohybrid Crosses
Here's a breakdown:
- Mono: Refers to one gene.
- Hybrid: Refers to offspring resulting from a cross between parents with different forms of a trait.
- Cross: Refers to the breeding of two individuals.
Therefore, a monohybrid cross focuses on tracking one specific trait as it passes from parent to offspring. The parents are usually homozygous for contrasting alleles of the trait, such as TT and tt, where T represents the dominant allele and t the recessive. The reference states: "The cross between two monohybrid traits (TT and tt) is called a Monohybrid Cross."
Example of a Monohybrid Cross
Let's use the example of pea plants and their height, a classic example used by Gregor Mendel.
- Assume that tallness (T) is dominant to shortness (t).
- A monohybrid cross would involve crossing a plant that is homozygous dominant (TT - tall) with a plant that is homozygous recessive (tt - short).
Here's how it breaks down:
| T | T | |
|---|---|---|
| t | Tt | Tt |
| t | Tt | Tt |
Outcomes
As shown in the table, all the offspring (F1 generation) will have the genotype Tt. Because T (tall) is dominant, all plants in the F1 generation will be tall.
Applications of Monohybrid Crosses
- Understanding Basic Inheritance: It helps to illustrate Mendel's laws of segregation.
- Predicting Genotypes and Phenotypes: Allows scientists to predict the possible genotypes and phenotypes of offspring.
- Agriculture: Useful in selective breeding programs to improve crop traits.
