AskDefine | Define fruitless

Dictionary Definition

fruitless adj : unproductive of success; "a fruitless search"; "futile years after her artistic peak"; "a sleeveless errand"; "a vain attempt" [syn: bootless, futile, sleeveless, vain]

User Contributed Dictionary



fruit + -less


  1. Useless; unproductive.
    The unskilled man's attempt at fixing his car engine was fruitless.
  2. Bearing no fruit; barren.
    The fruitless woman desperately wanted to have children.


useless; unproductive
bearing no fruit; barren

Extensive Definition

The fruitless gene (fru) is a Drosophila melanogaster gene that encodes several variants of a transcription factor protein. Normal fruitless function is required for proper development of several anatomical structures necessary for courtship, including motor neurons which innervate muscles needed for fly sexual behaviors and behaviors such as gender-specific aggression.


Male flies with mutations in the fruitless gene display altered sexual behavior. Fruitfly courtship, which involves a complex male-initiated ritual, may be disrupted in a number of ways by mutated fru alleles; fru is necessary for every step in the ritual. Some alleles prevent courting entirely, while others disrupt individual components. Notably, some loss-of-function alleles change or remove sexual preference.
Although many genes are known to be involved in male courtship behavior, the fruitless gene has been considered noteworthy because it exhibits sex-specific alternative splicing. When females produce the male-spliced gene product, they behave as males. Males with the female-spliced gene product exhibit complete loss of male courtship behavior and sexual orientation..
Some of the controversy may be due to the complexity of the fruitless gene locus, which is still incompletely understood. fruitless has at least four promoters, each encoding proteins with a beta-turn-beta domain containing a zinc finger motif. Alternative splicing occurs at both the 5' and 3' ends, and there are several variants (other than the male- and female-specific splicing patterns)., any subset of which may actually regulate behavior.


Early work refers to the gene as fruity, an apparent pun on both the common name of D. melanogaster, the fruit fly, as well as a slang word for homosexual. As social attitudes towards homosexuality changed, fruity came to be regarded as offensive, or at best, not politically correct. Thus, the gene was re-dubbed fruitless, alluding to the lack of offspring produced by flies with the mutation. However, it should be noted that -- despite the original name and a continuing history of misleading inferences by some researchers and science reporters -- fruitless mutants primarily show defects in male-female courtship, with no significant alteration in male-male or female-female courtship. Thus, evidence is not consistent with the idea that fruitless is any sort of 'gay gene'.


fruitless in German: fruitless

Synonyms, Antonyms and Related Words

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