A monohybrid cross involves the breeding of two individuals that differ in only one trait. The Punnett square is a tool used to predict the possible offspring of such a cross. Let's use the example of a monohybrid cross between two pea plants that differ in their seed shape, where round seeds (R) are dominant over wrinkled seeds (r).
Parent 1: RR (round seed)
Parent 2: rr (wrinkled seed)
To create a Punnett square, we write the genotype of each parent along the top and left side of a grid, and then combine each pair of alleles to create the possible genotypes of the offspring in the boxes.
R R
r Rr Rr
r Rr Rr
From this Punnett square, we can see that all the offspring will have the genotype Rr, meaning they will all be heterozygous for the seed shape trait. The phenotype, or physical appearance, of the offspring will be round, as the dominant R allele masks the recessive r allele.
Therefore, in this monohybrid cross, the round seed shape trait is dominant, while the wrinkled seed shape trait is recessive.
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Answer:
A monohybrid cross involves the breeding of two individuals that differ in only one trait. The Punnett square is a tool used to predict the possible offspring of such a cross. Let's use the example of a monohybrid cross between two pea plants that differ in their seed shape, where round seeds (R) are dominant over wrinkled seeds (r).
Parent 1: RR (round seed)
Parent 2: rr (wrinkled seed)
To create a Punnett square, we write the genotype of each parent along the top and left side of a grid, and then combine each pair of alleles to create the possible genotypes of the offspring in the boxes.
R R
r Rr Rr
r Rr Rr
From this Punnett square, we can see that all the offspring will have the genotype Rr, meaning they will all be heterozygous for the seed shape trait. The phenotype, or physical appearance, of the offspring will be round, as the dominant R allele masks the recessive r allele.
Therefore, in this monohybrid cross, the round seed shape trait is dominant, while the wrinkled seed shape trait is recessive.