Some dioecious species have the XY genotype for male and XX for female. After double fertilization, what would be the genotypes of the embryos and endosperm nuclei?
A) embryo XY/endosperm XXX or embryo XX/endosperm XXY
B) embryo XX/endosperm XX or embryo XY/endosperm XY
C) embryo XX/endosperm XXX or embryo XY/endosperm XYY
D) embryo XX/endosperm XXX or embryo XY/endosperm XXY

Question

Some dioecious species have the XY genotype for male and XX for female. After double fertilization, what would be the genotypes of the embryos and endosperm nuclei?
A) embryo XY/endosperm XXX or embryo XX/endosperm XXY
B) embryo XX/endosperm XX or embryo XY/endosperm XY
C) embryo XX/endosperm XXX or embryo XY/endosperm XYY
D) embryo XX/endosperm XXX or embryo XY/endosperm XXY

Quizplus · Accepted Answer

In dioecious species with the XY genotype for male and XX for female, after double fertilization, the embryos would be either XX or XY depending on the sperm that fuses with the egg cell. The endosperm, however, would be triploid with three nuclei, resulting in either XXX or XXY depending on the sperm's contribution to the fertilization of the central cell. Therefore, the correct option is D, where the embryos can be either XX or XY, and the endosperm can be either XXX or XXY.

Some Dioecious Species Have the XY Genotype for Male and XX