Question

In pigeons, a dominant allele c causes a checkered pattern in the feathers; its recessive allele c produces a plain pattern. Feather coloration is controlled by an independently assorting gene; the dominant allele b produces red feathers, and the recessive allele b produces brown feathers. Birds from a true-breeding checkered, red variety are crossed to birds from a true-breeding plain, brown variety. What will be the genotype and phenotype of the F1 generation?

1) All F1 birds will have the genotype CcBb and the phenotype checkered red feathers
2) All F1 birds will have the genotype CcBb and the phenotype plain brown feathers
3) All F1 birds will have the genotype CcBb and the phenotype checkered brown feathers
4) All F1 birds will have the genotype CcBb and the phenotype plain red feathers

Answer 1

The F1 generation from a cross between true-breeding checkered, red pigeons (CCBB) and plain, brown pigeons (ccbb) will all have the genotype CcBb. Due to the dominance of the C allele for checkered pattern and B allele for red color, the phenotype of all F1 pigeons will be checkered red feathers. Option 1 is correct answer.

Step-by-step explanation:

When analyzing the genetic cross between true-breeding pigeons for feather patterns and colors, we are discussing Mendelian genetics involving independently assorting genes. The fact that these genes assort independently means they are located on different chromosomes and segregate independently during gamete formation.

Given that the first true-breeding variety is checkered red (CCBB) and the second is plain brown (ccbb), all the F1 offspring must inherit one dominant and one recessive allele for each trait since they are heterozygous.

Therefore, the genotype for the feather pattern will be Cc and for the feather color it will be Bb. Due to the dominance of the C and B alleles, the phenotype of the F1 generation will exhibit the checkered pattern and red feathers, corresponding to the dominant alleles they possess.

Thus, option 1) is the correct answer: All F1 birds will have the genotype CcBb and the phenotype checkered red feathers.