GEPHE SUMMARY
Gephebase Gene
Entry Status
Published
GepheID
GP00001085
Main curator
Courtier
PHENOTYPIC CHANGE
Trait Category
Trait State in Taxon A
Drosophila simulans; D. mauritiana : more trichomes
Trait State in Taxon B
Drosophila sechellia : fewer trichomes
Ancestral State
Taxon A
Taxonomic Status
Taxon A #1
Common Name
-
Synonyms
-
Rank
species
Lineage
Show more ... Brachycera; Muscomorpha; Eremoneura; Cyclorrhapha; Schizophora; Acalyptratae; Ephydroidea; Drosophilidae; Drosophilinae; Drosophilini; Drosophila; Sophophora; melanogaster group; melanogaster subgroup
NCBI Taxonomy ID
is Taxon A an Infraspecies?
No
Taxon A #2
Common Name
-
Synonyms
-
Rank
species
Lineage
Show more ... Brachycera; Muscomorpha; Eremoneura; Cyclorrhapha; Schizophora; Acalyptratae; Ephydroidea; Drosophilidae; Drosophilinae; Drosophilini; Drosophila; Sophophora; melanogaster group; melanogaster subgroup
NCBI Taxonomy ID
is Taxon A an Infraspecies?
No
Taxon B
Common Name
-
Synonyms
Drosophila sechellia Tsacas and Bachli, 1981
Rank
species
Lineage
Show more ... Brachycera; Muscomorpha; Eremoneura; Cyclorrhapha; Schizophora; Acalyptratae; Ephydroidea; Drosophilidae; Drosophilinae; Drosophilini; Drosophila; Sophophora; melanogaster group; melanogaster subgroup
NCBI Taxonomy ID
is Taxon B an Infraspecies?
No
GENOTYPIC CHANGE
Generic Gene Name
ovo
Synonyms
CG15467; CG6824; Dmel\CG6824; Fs(1)K1103; fs(1)K1237; Fs(1)K1237; Fs(1)K155; fs(1)M1; fs(1)M38; Ovo; OVO; Ovo-D; ovo/shavenbaby; ovo/svb; ovoD; Shv; svb; Svb; Svb/Ovo
Sequence Similarities
-
UniProtKB
Drosophila melanogaster
GenebankID or UniProtKB
Mutation #1
Presumptive Null
No
Molecular Type
Aberration Type
Molecular Details of the Mutation
Enhancer A
Experimental Evidence
Authors
McGregor AP; Orgogozo V; Delon I; Zanet J; Srinivasan DG; Payre F; Stern DL
Abstract
One central, and yet unsolved, question in evolutionary biology is the relationship between the genetic variants segregating within species and the causes of morphological differences between species. The classic neo-darwinian view postulates that species differences result from the accumulation of small-effect changes at multiple loci. However, many examples support the possible role of larger abrupt changes in the expression of developmental genes in morphological evolution. Although this evidence might be considered a challenge to a neo-darwinian micromutationist view of evolution, there are currently few examples of the actual genes causing morphological differences between species. Here we examine the genetic basis of a trichome pattern difference between Drosophila species, previously shown to result from the evolution of a single gene, shavenbaby (svb), probably through cis-regulatory changes. We first identified three distinct svb enhancers from D. melanogaster driving reporter gene expression in partly overlapping patterns that together recapitulate endogenous svb expression. All three homologous enhancers from D. sechellia drive expression in modified patterns, in a direction consistent with the evolved svb expression pattern. To test the influence of these enhancers on the actual phenotypic difference, we conducted interspecific genetic mapping at a resolution sufficient to recover multiple intragenic recombinants. This functional analysis revealed that independent genetic regions upstream of svb that overlap the three identified enhancers are collectively required to generate the D. sechellia trichome pattern. Our results demonstrate that the accumulation of multiple small-effect changes at a single locus underlies the evolution of a morphological difference between species. These data support the view that alleles of large effect that distinguish species may sometimes reflect the accumulation of multiple mutations of small effect at select genes.
Additional References
Mutation #2
Presumptive Null
No
Molecular Type
Aberration Type
Molecular Details of the Mutation
Enhancer 7
Experimental Evidence
Authors
McGregor AP; Orgogozo V; Delon I; Zanet J; Srinivasan DG; Payre F; Stern DL
Abstract
One central, and yet unsolved, question in evolutionary biology is the relationship between the genetic variants segregating within species and the causes of morphological differences between species. The classic neo-darwinian view postulates that species differences result from the accumulation of small-effect changes at multiple loci. However, many examples support the possible role of larger abrupt changes in the expression of developmental genes in morphological evolution. Although this evidence might be considered a challenge to a neo-darwinian micromutationist view of evolution, there are currently few examples of the actual genes causing morphological differences between species. Here we examine the genetic basis of a trichome pattern difference between Drosophila species, previously shown to result from the evolution of a single gene, shavenbaby (svb), probably through cis-regulatory changes. We first identified three distinct svb enhancers from D. melanogaster driving reporter gene expression in partly overlapping patterns that together recapitulate endogenous svb expression. All three homologous enhancers from D. sechellia drive expression in modified patterns, in a direction consistent with the evolved svb expression pattern. To test the influence of these enhancers on the actual phenotypic difference, we conducted interspecific genetic mapping at a resolution sufficient to recover multiple intragenic recombinants. This functional analysis revealed that independent genetic regions upstream of svb that overlap the three identified enhancers are collectively required to generate the D. sechellia trichome pattern. Our results demonstrate that the accumulation of multiple small-effect changes at a single locus underlies the evolution of a morphological difference between species. These data support the view that alleles of large effect that distinguish species may sometimes reflect the accumulation of multiple mutations of small effect at select genes.
Additional References
Mutation #3
Presumptive Null
No
Molecular Type
Aberration Type
Molecular Details of the Mutation
Enhancer Z
Experimental Evidence
Authors
Frankel N; Davis GK; Vargas D; Wang S; Payre F; Stern DL
Abstract
Genes include cis-regulatory regions that contain transcriptional enhancers. Recent reports have shown that developmental genes often possess multiple discrete enhancer modules that drive transcription in similar spatio-temporal patterns: primary enhancers located near the basal promoter and secondary, or 'shadow', enhancers located at more remote positions. It has been proposed that the seemingly redundant activity of primary and secondary enhancers contributes to phenotypic robustness. We tested this hypothesis by generating a deficiency that removes two newly discovered enhancers of shavenbaby (svb, a transcript of the ovo locus), a gene encoding a transcription factor that directs development of Drosophila larval trichomes. At optimal temperatures for embryonic development, this deficiency causes minor defects in trichome patterning. In embryos that develop at both low and high extreme temperatures, however, absence of these secondary enhancers leads to extensive loss of trichomes. These temperature-dependent defects can be rescued by a transgene carrying a secondary enhancer driving transcription of the svb cDNA. Finally, removal of one copy of wingless, a gene required for normal trichome patterning, causes a similar loss of trichomes only in flies lacking the secondary enhancers. These results support the hypothesis that secondary enhancers contribute to phenotypic robustness in the face of environmental and genetic variability.
Additional References
Mutation #4
Presumptive Null
No
Molecular Type
Aberration Type
Molecular Details of the Mutation
Enhancer DG2
Experimental Evidence
Authors
Frankel N; Davis GK; Vargas D; Wang S; Payre F; Stern DL
Abstract
Genes include cis-regulatory regions that contain transcriptional enhancers. Recent reports have shown that developmental genes often possess multiple discrete enhancer modules that drive transcription in similar spatio-temporal patterns: primary enhancers located near the basal promoter and secondary, or 'shadow', enhancers located at more remote positions. It has been proposed that the seemingly redundant activity of primary and secondary enhancers contributes to phenotypic robustness. We tested this hypothesis by generating a deficiency that removes two newly discovered enhancers of shavenbaby (svb, a transcript of the ovo locus), a gene encoding a transcription factor that directs development of Drosophila larval trichomes. At optimal temperatures for embryonic development, this deficiency causes minor defects in trichome patterning. In embryos that develop at both low and high extreme temperatures, however, absence of these secondary enhancers leads to extensive loss of trichomes. These temperature-dependent defects can be rescued by a transgene carrying a secondary enhancer driving transcription of the svb cDNA. Finally, removal of one copy of wingless, a gene required for normal trichome patterning, causes a similar loss of trichomes only in flies lacking the secondary enhancers. These results support the hypothesis that secondary enhancers contribute to phenotypic robustness in the face of environmental and genetic variability.
Additional References
Mutation #5
Presumptive Null
No
Molecular Type
Aberration Type
SNP
Molecular Details of the Mutation
Enhancer E6; first epistatic mutation (5 in total)
Experimental Evidence
Authors
Frankel N; Erezyilmaz DF; McGregor AP; Wang S; Payre F; Stern DL
Abstract
Morphology evolves often through changes in developmental genes, but the causal mutations, and their effects, remain largely unknown. The evolution of naked cuticle on larvae of Drosophila sechellia resulted from changes in five transcriptional enhancers of shavenbaby (svb), a transcript of the ovo locus that encodes a transcription factor that governs morphogenesis of microtrichiae, hereafter called 'trichomes'. Here we show that the function of one of these enhancers evolved through multiple single-nucleotide substitutions that altered both the timing and level of svb expression. The consequences of these nucleotide substitutions on larval morphology were quantified with a novel functional assay. We found that each substitution had a relatively small phenotypic effect, and that many nucleotide changes account for this large morphological difference. In addition, we observed that the substitutions had non-additive effects. These data provide unprecedented resolution of the phenotypic effects of substitutions and show how individual nucleotide changes in a transcriptional enhancer have caused morphological evolution.
Mutation #6
Presumptive Null
No
Molecular Type
Aberration Type
SNP
Molecular Details of the Mutation
Enhancer E6; 2nd epistatic mutation (5 in total)
Experimental Evidence
Authors
Frankel N; Erezyilmaz DF; McGregor AP; Wang S; Payre F; Stern DL
Abstract
Morphology evolves often through changes in developmental genes, but the causal mutations, and their effects, remain largely unknown. The evolution of naked cuticle on larvae of Drosophila sechellia resulted from changes in five transcriptional enhancers of shavenbaby (svb), a transcript of the ovo locus that encodes a transcription factor that governs morphogenesis of microtrichiae, hereafter called 'trichomes'. Here we show that the function of one of these enhancers evolved through multiple single-nucleotide substitutions that altered both the timing and level of svb expression. The consequences of these nucleotide substitutions on larval morphology were quantified with a novel functional assay. We found that each substitution had a relatively small phenotypic effect, and that many nucleotide changes account for this large morphological difference. In addition, we observed that the substitutions had non-additive effects. These data provide unprecedented resolution of the phenotypic effects of substitutions and show how individual nucleotide changes in a transcriptional enhancer have caused morphological evolution.
Mutation #7
Presumptive Null
No
Molecular Type
Aberration Type
SNP
Molecular Details of the Mutation
Enhancer E6; 3rd epistatic mutation (5 in total)
Experimental Evidence
Authors
Frankel N; Erezyilmaz DF; McGregor AP; Wang S; Payre F; Stern DL
Abstract
Morphology evolves often through changes in developmental genes, but the causal mutations, and their effects, remain largely unknown. The evolution of naked cuticle on larvae of Drosophila sechellia resulted from changes in five transcriptional enhancers of shavenbaby (svb), a transcript of the ovo locus that encodes a transcription factor that governs morphogenesis of microtrichiae, hereafter called 'trichomes'. Here we show that the function of one of these enhancers evolved through multiple single-nucleotide substitutions that altered both the timing and level of svb expression. The consequences of these nucleotide substitutions on larval morphology were quantified with a novel functional assay. We found that each substitution had a relatively small phenotypic effect, and that many nucleotide changes account for this large morphological difference. In addition, we observed that the substitutions had non-additive effects. These data provide unprecedented resolution of the phenotypic effects of substitutions and show how individual nucleotide changes in a transcriptional enhancer have caused morphological evolution.
Mutation #8
Presumptive Null
No
Molecular Type
Aberration Type
SNP
Molecular Details of the Mutation
Enhancer E6; 4th epistatic mutation (5 in total)
Experimental Evidence
Authors
Frankel N; Erezyilmaz DF; McGregor AP; Wang S; Payre F; Stern DL
Abstract
Morphology evolves often through changes in developmental genes, but the causal mutations, and their effects, remain largely unknown. The evolution of naked cuticle on larvae of Drosophila sechellia resulted from changes in five transcriptional enhancers of shavenbaby (svb), a transcript of the ovo locus that encodes a transcription factor that governs morphogenesis of microtrichiae, hereafter called 'trichomes'. Here we show that the function of one of these enhancers evolved through multiple single-nucleotide substitutions that altered both the timing and level of svb expression. The consequences of these nucleotide substitutions on larval morphology were quantified with a novel functional assay. We found that each substitution had a relatively small phenotypic effect, and that many nucleotide changes account for this large morphological difference. In addition, we observed that the substitutions had non-additive effects. These data provide unprecedented resolution of the phenotypic effects of substitutions and show how individual nucleotide changes in a transcriptional enhancer have caused morphological evolution.
Mutation #9
Presumptive Null
No
Molecular Type
Aberration Type
Deletion Size
1-9 bp
Molecular Details of the Mutation
Enhancer E6; 5th epistatic mutation = 1-bp deletion (5 in total)
Experimental Evidence
Authors
Frankel N; Erezyilmaz DF; McGregor AP; Wang S; Payre F; Stern DL
Abstract
Morphology evolves often through changes in developmental genes, but the causal mutations, and their effects, remain largely unknown. The evolution of naked cuticle on larvae of Drosophila sechellia resulted from changes in five transcriptional enhancers of shavenbaby (svb), a transcript of the ovo locus that encodes a transcription factor that governs morphogenesis of microtrichiae, hereafter called 'trichomes'. Here we show that the function of one of these enhancers evolved through multiple single-nucleotide substitutions that altered both the timing and level of svb expression. The consequences of these nucleotide substitutions on larval morphology were quantified with a novel functional assay. We found that each substitution had a relatively small phenotypic effect, and that many nucleotide changes account for this large morphological difference. In addition, we observed that the substitutions had non-additive effects. These data provide unprecedented resolution of the phenotypic effects of substitutions and show how individual nucleotide changes in a transcriptional enhancer have caused morphological evolution.
RELATED GEPHE
Related Genes
Related Haplotypes
No matches found.
COMMENTS
@SeveralMutationsWithEffect - Entry validated by Ella Preger-Ben-Noon
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