Monohybrid crosses are an important idea in genetics. They help us understand how a single trait, like height, is passed down from parents to their offspring.
In these crosses, we look at parents that only differ in one trait. For example, we can compare tall pea plants (T) with short pea plants (t).
Alleles: Traits are controlled by alleles. Alleles are different versions of a gene. In our case, tall (T) is the dominant allele, while short (t) is the recessive allele.
Segregation: When cells are made for reproduction, the two alleles for a trait separate. This means each cell only carries one allele. For a parent with the genotype Tt, the possible alleles are T and t.
Punnett Squares: We use Punnett squares to help visualize genetic crosses. If we take two tall plants that are both Tt and cross them (Tt x Tt), we can set it up like this:
From this Punnett square, we can figure out the possible combinations of offspring:
Phenotypic Ratios: The results from this cross show us that we can expect 75% of the plants to be tall and 25% to be short. This gives us a ratio of 3 tall plants for every 1 short plant.
By understanding these ideas—alleles, segregation, and Punnett squares—monohybrid crosses show us the basic rules of inheritance in genetics. They help make the patterns of how traits are passed down easier to understand.
Monohybrid crosses are an important idea in genetics. They help us understand how a single trait, like height, is passed down from parents to their offspring.
In these crosses, we look at parents that only differ in one trait. For example, we can compare tall pea plants (T) with short pea plants (t).
Alleles: Traits are controlled by alleles. Alleles are different versions of a gene. In our case, tall (T) is the dominant allele, while short (t) is the recessive allele.
Segregation: When cells are made for reproduction, the two alleles for a trait separate. This means each cell only carries one allele. For a parent with the genotype Tt, the possible alleles are T and t.
Punnett Squares: We use Punnett squares to help visualize genetic crosses. If we take two tall plants that are both Tt and cross them (Tt x Tt), we can set it up like this:
From this Punnett square, we can figure out the possible combinations of offspring:
Phenotypic Ratios: The results from this cross show us that we can expect 75% of the plants to be tall and 25% to be short. This gives us a ratio of 3 tall plants for every 1 short plant.
By understanding these ideas—alleles, segregation, and Punnett squares—monohybrid crosses show us the basic rules of inheritance in genetics. They help make the patterns of how traits are passed down easier to understand.