Use of Double Mutants Has Been Invaluable in Studying Developmental

question 19

Multiple Choice

Use of double mutants has been invaluable in studying developmental pathways. In C. elegans, sex is determined by the ratio of sets of autosomes to X chromosomes. A diploid male has one X, and diploid hermaphrodites have two X's. The loss- of- function gene her- 1 produces XO worms that are hermaphrodites, but XX worms are unaffected. Mutation of a second gene, tra, causes the XX to develop as male. Given this information, what would be the phenotype of a tra, her- 1 double mutant?

• A) lethality
• B) a hermaphrodite
• C) an intersex variant
• D) a male nematode
• E) a female nematode

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