Question

A BbGg x bbgg cross yields a phenotypic ratio of approximately 5 black eyes, green skin : 5 orange eyes, white skin : 1 black eyes, white skin : 1 orange eyes, green skin. Which of the following best explains these results?
A.Mendel's laws of segregation and independent assortment are being violated.
B.The heterozygous individual is male, and the homozygous individual is female.
C.The genes for eye color and skin color are co-dominant.
D.Mendel's law of independent assortment is being violated.
E. Mendel's law of segregation is being violated.

Answer 1

Answer:

D.Mendel's law of independent assortment is being violated.

Explanation:

According to Mendel in his law of independent assortment, the allele of one gene gets sorted into gametes independently of the allele of another gene. He discovered this when he performed a cross involving two characters i.e. dihybrid cross, which he obtained a F2 phenotypic ratio of 9:3:3:1. This ratio is only possible if each allele of each gene is represented in each gamete i.e. a dominant allele of the first gene is equally likely possible to be contained with a dominant or recessive allele in the second gene.

If this occurs according to the Mendel's law of independent assortment, a total of four possible combinations of gametes should be produced by each parent organism. When this 4 gametes are crossed in a punnet square, a total of 16 offsprings will be possible.

However, in this case, a total of 12 offsprings were produced, depicting that the alleles did not separate independently of one another to produce four possible gametes.