Question

In a group of cockatiels, some individuals have bright orange cheeks and others have pale orange cheeks. in this group, the gene for the cheek color trait has two alleles. the allele for bright orange cheeks (r) is dominant over the allele for pale orange cheeks (r). complete the punnett square below to show all possible genotypes of the offspring from a cross between two cockatiels.

Answer 1

The Punnett square for a cross between two cockatiels with heterozygous cheek color traits consists of 25% chance of being homozygous dominant (RR, bright orange cheeks), 50% chance of being heterozygous (Rr, also bright orange due to dominance), and 25% chance of being homozygous recessive (rr, pale orange cheeks).

Step-by-step explanation:

In this case, where we are considering the trait for cheek color in cockatiels, we're assuming that the parents cross completely consists of heterozygotes. To complete a Punnett square for this scenario, first, we will list the genotype each parent can provide to an offspring. For both parents being heterozygous (meaning they both carry dominant and recessive alleles, or Rr), cross all possible combinations of alleles from one parent with those from the other parent.

This produces the following punnett square:
| R | r
R | RR | Rr
r | Rr | rr

As per the table, each offspring has a 25% chance of being homozygous dominant (RR, bright orange cheeks), a 50% chance of being heterozygous (Rr, also bright orange due to dominance), and a 25% chance of being homozygous recessive (rr, pale orange cheeks).

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