The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome
Inversions are portions of a chromosome where the gene order is reversed relative to a standard reference orientation. Because of reduced levels of recombination in heterokaryotypes, inversions have a potentially important effect on patterns of nucleotide variability in those genomic regions close t...
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2003
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| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07374038_v20_n6_p931_Laayouni http://hdl.handle.net/20.500.12110/paper_07374038_v20_n6_p931_Laayouni |
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paper:paper_07374038_v20_n6_p931_Laayouni2025-07-30T18:20:49Z The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome Drosophila buzzatii Inversion polymorphism Nucleotide variability Sequence-tagged sites article chromosome inversion DNA polymorphism Drosophila drosophila buzzatii gene rearrangement genetic variability molecular evolution nonhuman nucleotide sequence sequence tagged site Animals Base Sequence Chromosomes DNA Drosophila Evolution, Molecular Linkage Disequilibrium Molecular Sequence Data Polymorphism, Genetic Sequence Homology, Nucleic Acid Sequence Tagged Sites Drosophila buzzatii Inversions are portions of a chromosome where the gene order is reversed relative to a standard reference orientation. Because of reduced levels of recombination in heterokaryotypes, inversions have a potentially important effect on patterns of nucleotide variability in those genomic regions close to, or included in, the inverted fragments. Here we report sequence variation at three anonymous regions (STSs) located at different positions in relation to second-chromosome inversion breakpoints in 29 isochromosomal lines derived from an Argentinean population of Drosophila buzzatii. In agreement with previous findings in Drosophila, gene flux (crossing over and/or gene conversion) between arrangements seems to appreciably increase as we approach the middle sections of inversion 2j, and patterns of nucleotide variability within, as well as genetic differentiation between chromosome arrangements, are comparable to those observed at the molecular marker outside the inverted fragments. On the other hand, nucleotide diversity near the proximal breakpoint of inversion 2j is reduced when contrasted with that found at the other regions, particularly in the case of derived inverted chromosomes. Using the data from the breakpoint, we estimate that the inversion polymorphism is approximately 1.63 N generations old, where N is the effective population size. An excess of low-frequency segregating polymorphisms is detected; mostly in the ancestral 2st arrangement and probably indicating a population expansion that predates the coalescent time of inversion 2j. Heterogeneity in mutation rates between the markers linked to the inversions may be sufficient to explain the different levels of nucleotide diversity observed. When considered in the context of other studies on patterns of variation relative to physical distance to inversion breakpoints, our data appear to be consistent with the conclusion that inversions are unlikely to be "long-lived" balanced polymorphisms. 2003 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07374038_v20_n6_p931_Laayouni http://hdl.handle.net/20.500.12110/paper_07374038_v20_n6_p931_Laayouni |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Drosophila buzzatii Inversion polymorphism Nucleotide variability Sequence-tagged sites article chromosome inversion DNA polymorphism Drosophila drosophila buzzatii gene rearrangement genetic variability molecular evolution nonhuman nucleotide sequence sequence tagged site Animals Base Sequence Chromosomes DNA Drosophila Evolution, Molecular Linkage Disequilibrium Molecular Sequence Data Polymorphism, Genetic Sequence Homology, Nucleic Acid Sequence Tagged Sites Drosophila buzzatii |
| spellingShingle |
Drosophila buzzatii Inversion polymorphism Nucleotide variability Sequence-tagged sites article chromosome inversion DNA polymorphism Drosophila drosophila buzzatii gene rearrangement genetic variability molecular evolution nonhuman nucleotide sequence sequence tagged site Animals Base Sequence Chromosomes DNA Drosophila Evolution, Molecular Linkage Disequilibrium Molecular Sequence Data Polymorphism, Genetic Sequence Homology, Nucleic Acid Sequence Tagged Sites Drosophila buzzatii The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| topic_facet |
Drosophila buzzatii Inversion polymorphism Nucleotide variability Sequence-tagged sites article chromosome inversion DNA polymorphism Drosophila drosophila buzzatii gene rearrangement genetic variability molecular evolution nonhuman nucleotide sequence sequence tagged site Animals Base Sequence Chromosomes DNA Drosophila Evolution, Molecular Linkage Disequilibrium Molecular Sequence Data Polymorphism, Genetic Sequence Homology, Nucleic Acid Sequence Tagged Sites Drosophila buzzatii |
| description |
Inversions are portions of a chromosome where the gene order is reversed relative to a standard reference orientation. Because of reduced levels of recombination in heterokaryotypes, inversions have a potentially important effect on patterns of nucleotide variability in those genomic regions close to, or included in, the inverted fragments. Here we report sequence variation at three anonymous regions (STSs) located at different positions in relation to second-chromosome inversion breakpoints in 29 isochromosomal lines derived from an Argentinean population of Drosophila buzzatii. In agreement with previous findings in Drosophila, gene flux (crossing over and/or gene conversion) between arrangements seems to appreciably increase as we approach the middle sections of inversion 2j, and patterns of nucleotide variability within, as well as genetic differentiation between chromosome arrangements, are comparable to those observed at the molecular marker outside the inverted fragments. On the other hand, nucleotide diversity near the proximal breakpoint of inversion 2j is reduced when contrasted with that found at the other regions, particularly in the case of derived inverted chromosomes. Using the data from the breakpoint, we estimate that the inversion polymorphism is approximately 1.63 N generations old, where N is the effective population size. An excess of low-frequency segregating polymorphisms is detected; mostly in the ancestral 2st arrangement and probably indicating a population expansion that predates the coalescent time of inversion 2j. Heterogeneity in mutation rates between the markers linked to the inversions may be sufficient to explain the different levels of nucleotide diversity observed. When considered in the context of other studies on patterns of variation relative to physical distance to inversion breakpoints, our data appear to be consistent with the conclusion that inversions are unlikely to be "long-lived" balanced polymorphisms. |
| title |
The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| title_short |
The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| title_full |
The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| title_fullStr |
The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| title_full_unstemmed |
The evolutionary history of Drosophila buzzatii. XXXV. Inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| title_sort |
evolutionary history of drosophila buzzatii. xxxv. inversion polymorphism and nucleotide variability in different regions of the second chromosome |
| publishDate |
2003 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_07374038_v20_n6_p931_Laayouni http://hdl.handle.net/20.500.12110/paper_07374038_v20_n6_p931_Laayouni |
| _version_ |
1840324585412624384 |