Fruitless (gene)

Last updated
fruitless
Identifiers
Organism Drosophila melanogaster
Symbolfru
Entrez 42226
RefSeq (mRNA) NM_169821.1
RefSeq (Prot) NP_732349.1
UniProt Q8IN81
Other data
Chromosome 3R: 14.22 - 14.39 Mb
Search for
Structures Swiss-model
Domains InterPro

The fruitless gene (fru) is a Drosophila melanogaster gene that encodes several variants of a putative 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. [1] The gene does not have an obvious mammalian homolog, but appears to function in sex determination in species as distant as the mosquito Anopheles gambiae. [2]

Contents

fruitless serves as an example of how a gene or a group of genes may regulate the development and/or function of neurons involved in innate behavior. Research on fruitless has received attention in the popular press, since it provokes discussion on genetics of human sexual orientation, [3] [4] and behaviors such as gender-specific aggression. [5]

Function

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 many 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. [1]

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 that do not produce the male-specific product do not court females and are infertile. [1] In the brain, a subset (ca. 2,000) of neurons express fruitless [6] and fruitless expression is sufficient to instruct sexually dimorphic connectivity. [7] [8]

fruitless has at least four promoters, each encoding proteins containing both a BTB (Broad complex/tramtrack/bric-a-brac) domain and 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). [1] The fruitless gene locus also controls the expression of hundreds of other genes, [9] any subset of which may actually regulate behavior.

Name

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. [10] However, despite the original name and a continuing history of misleading inferences by the popular media, fruitless mutants primarily show defects in male-female courtship, though certain mutants cause male-male or female-female courtship. [11]

Related Research Articles

<i>Drosophila</i> Genus of flies

Drosophila is a genus of flies, belonging to the family Drosophilidae, whose members are often called "small fruit flies" or pomace flies, vinegar flies, or wine flies, a reference to the characteristic of many species to linger around overripe or rotting fruit. They should not be confused with the Tephritidae, a related family, which are also called fruit flies ; tephritids feed primarily on unripe or ripe fruit, with many species being regarded as destructive agricultural pests, especially the Mediterranean fruit fly.

<i>Drosophila melanogaster</i> Species of fruit fly

Drosophila melanogaster is a species of fly in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly", or "banana fly". In the wild, D. melanogaster are attracted to rotting fruit and fermenting beverages, and are often found in orchards, kitchens and pubs.

<span class="mw-page-title-main">Mosaic (genetics)</span> Condition in multi-cellular organisms

Mosaicism or genetic mosaicism is a condition in which a multicellular organism possesses more than one genetic line as the result of genetic mutation. This means that various genetic lines resulted from a single fertilized egg. Mosaicism is one of several possible causes of chimerism, wherein a single organism is composed of cells with more than one distinct genotype.

cGMP-dependent protein kinase Protein kinase

cGMP-dependent protein kinase or protein kinase G (PKG) is a serine/threonine-specific protein kinase that is activated by cGMP. It phosphorylates a number of biologically important targets and is implicated in the regulation of smooth muscle relaxation, platelet function, sperm metabolism, cell division, and nucleic acid synthesis.

Intragenomic conflict refers to the evolutionary phenomenon where genes have phenotypic effects that promote their own transmission in detriment of the transmission of other genes that reside in the same genome. The selfish gene theory postulates that natural selection will increase the frequency of those genes whose phenotypic effects cause their transmission to new organisms, and most genes achieve this by cooperating with other genes in the same genome to build an organism capable of reproducing and/or helping kin to reproduce. The assumption of the prevalence of intragenomic cooperation underlies the organism-centered concept of inclusive fitness. However, conflict among genes in the same genome may arise both in events related to reproduction and altruism.

Transvection is an epigenetic phenomenon that results from an interaction between an allele on one chromosome and the corresponding allele on the homologous chromosome. Transvection can lead to either gene activation or repression. It can also occur between nonallelic regions of the genome as well as regions of the genome that are not transcribed.

<span class="mw-page-title-main">Sexual conflict</span> Term in evolutionary biology

Sexual conflict or sexual antagonism occurs when the two sexes have conflicting optimal fitness strategies concerning reproduction, particularly over the mode and frequency of mating, potentially leading to an evolutionary arms race between males and females. In one example, males may benefit from multiple matings, while multiple matings may harm or endanger females, due to the anatomical differences of that species. Sexual conflict underlies the evolutionary distinction between male and female.

<span class="mw-page-title-main">White (mutation)</span>

white, abbreviated w, was the first sex-linked mutation discovered, found in the fruit fly Drosophila melanogaster. In 1910 Thomas Hunt Morgan and Lilian Vaughan Morgan collected a single male white-eyed mutant from a population of Drosophila melanogaster fruit flies, which usually have dark brick red compound eyes. Upon crossing this male with wild-type female flies, they found that the offspring did not conform to the expectations of Mendelian inheritance. The first generation produced 1,237 red-eyed offspring and three white-eyed male flies. The second generation produced 2,459 red-eyed females, 1,011 red-eyed males, and 782 white-eyed males. Further experimental crosses led them to the conclusion that this mutation was somehow physically connected to the "factor" that determined sex in Drosophila. This led to the discovery of sex linkage, in which the gene for a trait is found on a sex chromosome. Morgan named this trait white, now abbreviated w. Flies possessing the white allele are frequently used to introduce high school and college students to genetics.

Paralytic is a gene in the fruit fly, Drosophila melanogaster, which encodes a voltage gated sodium channel within D. melanogaster neurons. This gene is essential for locomotive activity in the fly. There are 9 different para alleles, composed of a minimum of 26 exons within over 78kb of genomic DNA. The para gene undergoes alternative splicing to produce subtypes of the channel protein. Flies with mutant forms of paralytic are used in fly models of seizures, since seizures can be easily induced in these flies.

The genetics of social behavior is an area of research that attempts to address the question of the role that genes play in modulating the neural circuits in the brain which influence social behavior. Model genetic species, such as D.melanogaster and Apis mellifera, have been rigorously studied and proven to be instrumental in developing the science of genetics. Many examples of genetic factors of social behavior have been derived from a bottom-up method of altering a gene and observing the change it produces in an organism. Sociogenomics is an integrated field that accounts for the complete cellular genetic complement of an organism from a top-down approach, accounting for all biotic influences that effect behavior on a cellular level.

<i>doublesex</i> Gene of insects

Doublesex (dsx) is a gene that is involved in the sex determination system of many insects including the fruit fly Drosophila melanogaster.

Interlocus sexual conflict is a type of sexual conflict that occurs through the interaction of a set of antagonistic alleles at two or more different loci, or the location of a gene on a chromosome, in males and females, resulting in the deviation of either or both sexes from the fitness optima for the traits. A co-evolutionary arms race is established between the sexes in which either sex evolves a set of antagonistic adaptations that is detrimental to the fitness of the other sex. The potential for reproductive success in one organism is strengthened while the fitness of the opposite sex is weakened. Interlocus sexual conflict can arise due to aspects of male–female interactions such as mating frequency, fertilization, relative parental effort, female remating behavior, and female reproductive rate.

A behaviour mutation is a genetic mutation that alters genes that control the way in which an organism behaves, causing their behavioural patterns to change.

mir-279 is a short RNA molecule found in Drosophila melanogaster that belongs to a class of molecules known as microRNAs. microRNAs are ~22nt-long non-coding RNAs that post-transcriptionally regulate the expression of genes, often by binding to the 3' untranslated region of mRNA, targeting the transcript for degradation. miR-279 has diverse tissue-specific functions in the fly, influencing developmental processes related to neurogenesis and oogenesis, as well as behavioral processes related to circadian rhythms. The varied roles of mir-279, both in the developing and adult fly, highlight the utility of microRNAs in regulating unique biological processes.

<i>Cycle</i> (gene)

Cycle (cyc) is a gene in Drosophila melanogaster that encodes the CYCLE protein (CYC). The Cycle gene (cyc) is expressed in a variety of cell types in a circadian manner. It is involved in controlling both the sleep-wake cycle and circadian regulation of gene expression by promoting transcription in a negative feedback mechanism. The cyc gene is located on the left arm of chromosome 3 and codes for a transcription factor containing a basic helix-loop-helix (bHLH) domain and a PAS domain. The 2.17 kb cyc gene is divided into 5 coding exons totaling 1,625 base pairs which code for 413 aminos acid residues. Currently 19 alleles are known for cyc. Orthologs performing the same function in other species include ARNTL and ARNTL2.

A Drosophila connectome is a list of neurons in the Drosophila melanogaster nervous system, and the chemical synapses between them. The fly's nervous system consists of the brain plus the ventral nerve cord, and both are known to differ considerably between male and female. Dense connectomes have been completed for the female adult brain, the male nerve cord, and the female larval stage. The available connectomes show only chemical synapses - other forms of inter-neuron communication such as gap junctions or neuromodulators are not represented. Drosophila is the most complex creature with a connectome, which had only been previously obtained for three other simpler organisms, first C. elegans. The connectomes have been obtained by the methods of neural circuit reconstruction, which over the course of many years worked up through various subsets of the fly brain to the almost full connectomes that exist today.

<span class="mw-page-title-main">Jeffrey C. Hall</span> American geneticist and chronobiologist (born 1945)

Jeffrey Connor Hall is an American geneticist and chronobiologist. Hall is Professor Emeritus of Biology at Brandeis University and currently resides in Cambridge, Maine.

Gregory Stephen Xavier Edward Jefferis is a British neuroscientist known for his work on the circuit basis of olfactory perception in the vinegar fly, Drosophila melanogaster. He is a tenured Programme Leader at the MRC Laboratory of Molecular Biology in Cambridge (UK) and associated with the Department of Zoology at the University of Cambridge.

Mariana Federica Wolfner is the Goldwin Smith Professor of molecular biology and genetics at Cornell University. Her research investigates sexual conflict in the fruit fly Drosophila melanogaster. She was elected a member of the National Academy of Sciences (NAS) in 2019 in recognition of her distinguished and continuing achievements in original research.

<span class="mw-page-title-main">Reinhard F. Stocker</span> Swiss biologist

Reinhard F. Stocker is a Swiss biologist. He pioneered the analysis of the sense of smell and taste in higher animals, using the fly Drosophila melanogaster as a study case. He provided a detailed account of the anatomy and development of the olfactory system, in particular across metamorphosis, for which he received the Théodore-Ott-Prize of the Swiss Academy of Medical Sciences in 2007, and pioneered the use of larval Drosophila for the brain and behavioural sciences.

References

  1. 1 2 3 4 Demir E, Dickson BJ (June 2005). "fruitless splicing specifies male courtship behavior in Drosophila". Cell. 121 (5): 785–94. doi: 10.1016/j.cell.2005.04.027 . PMID   15935764. S2CID   14663286.
  2. ↑ Gailey DA, Billeter JC, Liu JH, Bauzon F, Allendorfer JB, Goodwin SF (March 2006). "Functional conservation of the fruitless male sex-determination gene across 250 Myr of insect evolution". Molecular Biology and Evolution. 23 (3): 633–43. doi: 10.1093/molbev/msj070 . PMID   16319090.
  3. ↑ Burr C (June 1997). "Homosexuality and Biology, The Genetic Quest". The Atlantic.
  4. ↑ Wade N (December 13, 1996). "Mating Game of Fruit Fly Is Traced to a Single Gene". The New York Times.
  5. ↑ Sample, Ian (November 20, 2006). "Flies reveal gene that makes girls fight like boys". The Guardian.
  6. ↑ Cachero S, Ostrovsky AD, Yu JY, Dickson BJ, Jefferis GS (September 2010). "Sexual dimorphism in the fly brain". Current Biology. 20 (18): 1589–601. Bibcode:2010CBio...20.1589C. doi:10.1016/j.cub.2010.07.045. PMC   2957842 . PMID   20832311.
  7. ↑ Kohl J, Ostrovsky AD, Frechter S, Jefferis GS (December 2013). "A bidirectional circuit switch reroutes pheromone signals in male and female brains". Cell. 155 (7): 1610–23. doi:10.1016/j.cell.2013.11.025. PMC   3898676 . PMID   24360281.
  8. ↑ Ruta V, Datta SR, Vasconcelos ML, Freeland J, Looger LL, Axel R (December 2010). "A dimorphic pheromone circuit in Drosophila from sensory input to descending output". Nature. 468 (7324): 686–90. Bibcode:2010Natur.468..686R. doi:10.1038/nature09554. PMID   21124455. S2CID   4412743.
  9. ↑ Goldman TD, Arbeitman MN (November 2007). "Genomic and functional studies of Drosophila sex hierarchy regulated gene expression in adult head and nervous system tissues". PLOS Genetics. 3 (11): e216. doi: 10.1371/journal.pgen.0030216 . PMC   2082469 . PMID   18039034.
  10. ↑ Gailey DA, Hall JC (April 1989). "Behavior and cytogenetics of fruitless in Drosophila melanogaster: different courtship defects caused by separate, closely linked lesions". Genetics. 121 (4): 773–85. doi:10.1093/genetics/121.4.773. PMC   1203660 . PMID   2542123.
  11. ↑ "GeneBrief - fruitless". InteractiveFly. Society for Developmental Biology.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.