Concept explainers
To review:
The
Introduction:
When the genes are present on X-chromosomes, it is known as X-linked trait. The example can be seen in Drosophila, where the genes for colored eyes are present on the X-chromosome. The red-colored eye is dominant in Drosophila over the white-colored eye.
Explanation of Solution
Genes for colored eyes in Drosophila are present on the X-chromosome. The white-colored eyes is an X-linked recessive trait found in Drosophila. The red-colored eyes are dominant in them.
Let
The cross can be made as:
Parents
Gametes
Gametes | |||
F1 female progeny is crossed with her father:
The cross can be made as:
Parents
Gametes
F1 progeny
Gametes | ||
So, the ratio of female progenies, red to white is 2:0 and for male progenies, red to white is 1:1.
Now,
The cross can be made as follows:
Parents
Gametes
Gametes | ||
Therefore, the ratio of red to white female progenies is
Thus, it can be concluded that when the F1 female progeny is crossed with her father, the ratio of female progenies, red to white, is 2:0, whereas, for male progenies, the ratio of red to white is 1:1. When the F1 male progeny is crossed with his mother, the ratio of female progenies, red to white, is 0:2, whereas, for male progenies, the ratio of red to white is 0:2.
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