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

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

Step-by-step explanation:

For independently assorting genes, a dihybrid test cross gives progeny in 1:1:1:1 ratio. Here, a dihybrid (BbGg) is crossed with a double homozygous recessive individual (bbgg). If the genes were assorted independently, four types of progeny would have been produced in 1:1:1:1 ratio.

However, the progeny has more proportion of offspring with black eyes, green skin, and orange eyes, white skin. This means that the genes for orange eyes and white skin are linked. Likewise, the genes for black eyes and green skin are linked. Linked genes do not assort independently and are one of the exceptions for Mendel's law of independent assortment.