Sex-linked traits Original Scenario-Based Download PDF

Questions

1. 1.

   In an orbital bio-reserve, researchers investigate crystal-tailed geckos that utilize an XY sex-determination system. Tail luminescence is governed by an X-linked gene where the dominant allele ($X^G$) produces radiant emerald light and the recessive allele ($X^g$) produces dull crimson light. A crimson female is crossed with an emerald male to produce an $F_1$ generation. If these $F_1$ individuals are allowed to mate with one another, what phenotypic distribution will appear among their $F_2$ offspring?

   • A) All female offspring will be emerald and all male offspring will be crimson.
   • B) Three-quarters of all offspring will be emerald and one-quarter will be crimson, with no phenotypic differences between sexes.
   • C) Half of the females and half of the males will be emerald, while the remaining half of each sex will be crimson.
   • D) All male offspring will be emerald, whereas the females will be split equally between emerald and crimson.