Chromosome Inversions
Mostrando 25-36 de 217 artigos, teses e dissertações.
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25. Cytotaxonomy of Simulium cauchense Floch & Abonnenc and Simulium quadrifidum Lutz (Diptera: Simuliidae) in Brazilian Amazonia
Simulium cauchense Floch & Abonnenc and Simulium quadrifidum Lutz are widely distributed in the Amazon region and are morphologically similar at the larval and pupal stages. Chromosomally, these species are readily distinguished by the position of the nucleolar organizer, which is in the short arm of chromosome I in S. cauchense and in the long arm of chromo
Memórias do Instituto Oswaldo Cruz. Publicado em: 2005-05
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26. Chromosomal inversion polymorphism in Drosophila mediopunctata: seasonal, altitudinal, and latitudinal variation
The most polymorphic chromosome for inversions in Drosophila mediopunctata is the chromosome II, where 17 inversions have been found, eight of which occurring in the distal region and nine in the proximal region. We present an analysis of the chromosome II inversion polymorphism with respect to seasonal, altitudinal and latitudinal variation. In D. mediopunc
Genetics and Molecular Biology. Publicado em: 2004
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27. Polytene chromosome map and inversion polymorphism in Drosophila mediopunctata
Drosophila mediopunctata belongs to the tripunctata group, and is one of the commonest Drosophila species collected in some places in Brazil, especially in the winter. A standard map of the polytene chromosomes is presented. The breakpoints of the naturally occurring chromosomal rearrangements are marked on the map. The distribution of breaking points throug
Memórias do Instituto Oswaldo Cruz. Publicado em: 2002-07
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28. The Genetics of DROSOPHILA SUBOBSCURA Populations. V. a Study of Linkage Disequilibrium in Natural Populations between Genes and Inversions of the E Chromosome
The genetics of Hk and Est-9 complex gene have been studied in Drosophila subobscura. While Hk alleles mendelize normally, Est-9 is a complex locus consisting of several very closely linked genes with active and silent alleles. Both genes are located on chromosome E; a detailed genetic map was constructed with the help of visible markers and inversions. Both
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29. Evolution of mouse chromosome 17 and the origin of inversions associated with t haplotypes.
Mouse t haplotypes are variant forms of chromosome 17 that exist at high frequencies in worldwide populations of several species of house mouse. They are known to differ from wild-type chromosomes with respect to two relative inversions referred to as proximal and distal. An untested assumption has been that these two inversions originated in the chromosomal
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30. The Fertility Effects of Pericentric Inversions in Drosophila Melanogaster
Heterozygotes for pericentric inversions are expected to be semisterile because recombination in the inverted region produces aneuploid gametes. Newly arising pericentric inversions should therefore be quickly eliminated from populations by natural selection. The occasional polymorphism for such inversions and their fixation among closely related species hav
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31. Variation of Spontaneous Occurrence Rates of Chromosomal Aberrations in the Second Chromosomes of DROSOPHILA MELANOGASTER
After accumulating mutations by the aid of marked inversions, spontaneous occurrence rates of chromosome aberrations were estimated for 1148 chromosome lines that originated from five stem line second chromosomes of Drosophila melanogaster. In chromosome lines originating from three stem chromosomes (CH, PQ, and RT), mutations were accumulated for 7550, 7252
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32. Gene Differences between Third-Chromosome Inversions of DROSOPHILA PSEUDOOBSCURA
Associations of alleles of the acid phosphatase-3 locus with the different third-chromosome inversions from different populations of D. pseudoobscura are described. We observe only the allele AP-3 1.0 in the Standard and Arrow-head inversions and the allele AP-3.98 in the Santa Cruz, Treeline, Cuernavaca and the Pikes Peak arrangements. The Chiricahua gene
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33. Construction of Chromosomal Rearrangements in Salmonella by Transduction: Inversions of Non-Permissive Segments Are Not Lethal
Homologous sequences placed in inverse order at particular separated sites in the bacterial chromosome (termed ``permissive'') can recombine to form an inversion of the intervening chromosome segment. When the same repeated sequences flank other chromosome segments (``non-permissive''), recombination occurs but the expected inversion rearrangement is not fou
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34. Ability of a Bacterial Chromosome Segment to Invert Is Dictated by Included Material Rather than Flanking Sequence
Homologous recombination between sequences present in inverse order within the same chromosome can result in inversion formation. We have previously shown that inverse order sequences at some sites (permissive) recombine to generate the expected inversion; no inversions are found when the same inverse order sequences flank other (nonpermissive) regions of th
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35. The Genetics of DROSOPHILA SUBOBSCURA Populations. IX. Studies on Linkage Disequilibrium in Four Natural Populations
Gametic frequencies were obtained in four natural populations of D. subobscura by extracting wild chromosomes and subsequently analyzing them for inversions and allozymes. The genes Lap and Pept-1, both located within the same inversions of chromosome O, were found in striking nonrandom associations with them of the same kind and degree in all populations st
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36. Selective Introgression of Paracentric Inversions between Two Sibling Species of the Anopheles Gambiae Complex
The Anopheles gambiae complex includes the major vectors of malaria in sub-Saharan Africa where >80% of all world-wide cases occur. These mosquitoes are characterized by chromosomal inversions associated to the speciation process and to intraspecific ecological and behavioral flexibility. It has been postulated that introgressive hybridization has selectivel