Frequency of Induced Breaks in Chromosomes of Drosophila Melanogaster

Kaufmann, Berwind Petersen; Demerec, Milislav

doi:10.1073/pnas.23.9.484

Cited by 24 publications

(3 citation statements)

References 4 publications

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“…Males also carry a submetacentric or metacentric Y chromosome. Salivary gland nuclei show six long banded euchromatic arms, consistent with earlier reports; [30][31][32][33] no banding is detected on the 4 th chromosome, suggesting that it is heterochromatic. In the meiotic nuclei of primary spermatocytes, a tetravalent between X, Y and 4 th chromosomes is observed in all species of the ananassae subgroup except the three members of the ercepeae complex (D. merina, D. vallismaia and D. ercepeae) ( Fig.…”

Section: Resultssupporting

confidence: 91%

Evolution in theDrosophila ananassaespecies subgroup

Matsuda¹,

Ng²,

Doi³

et al. 2009

Fly

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Drosophila ananassae and its relatives have many advantages as a model of genetic differentiation and speciation. In this report, we examine evolutionary relationships in the ananassae species subgroup using a multi-locus molecular data set, karyotypes, meiotic chromosome configuration, chromosomal inversions, morphological traits, and patterns of reproductive isolation. We describe several new taxa that are the closest known relatives of D. ananassae. Analysis of Y-chromosomal and mitochondrial haplotypes, shared chromosome arrangements, pre-mating isolation and hybrid male sterility suggests that these taxa represent a recent evolutionary radiation and may experience substantial gene flow. We discuss possible evolutionary histories of these species and give a formal description of one of them as D. parapallidosa Tobari sp. n. The comparative framework established by this study, combined with the recent sequencing of the D. ananassae genome, will facilitate future studies of reproductive isolation, phenotypic variation and genome evolution in this lineage.

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Section: Resultssupporting

confidence: 91%

Evolution in theDrosophila ananassaespecies subgroup

Matsuda¹,

Ng²,

Doi³

et al. 2009

Fly

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“…This could be due to some aspect of the structure of IH or to the fact that these regions simply contain more DNA than other regions, DNA that is more highly compacted in polytene chromosomes. Kaufmann and Demerec (1937) concluded that break frequency in the heterochromatic Y chromosome was proportional to the length of this chromosome in metaphase. Further analysis of a wealth of cytological material (Bauer et al 1938;Kaufmann 1946) demonstrated that break frequency in the pericentric heterochromatin and euchromatic arm of the X chromosome is also proportional to the respective lengths of the heterochromatic region and the euchromatic arm of this chromosome during mitosis.…”

Section: Does Ectopic Pairing Results From Underreplication?mentioning

confidence: 99%

Intercalary heterochromatin in polytene chromosomes of Drosophila melanogaster

et al. 2008

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Intercalary heterochromatin consists of extended chromosomal domains which are interspersed throughout the euchromatin and contain silent genetic material. These domains comprise either clusters of functionally unrelated genes or tandem gene duplications and possibly stretches of noncoding sequences. Strong repression of genetic activity means that intercalary heterochromatin displays properties that are normally attributable to classic pericentric heterochromatin: high compaction, late replication and underreplication in polytene chromosomes, and the presence of heterochromatin-specific proteins. Late replication and underreplication occurs when the suppressor of underreplication protein is present in intercalary heterochromatic regions. Intercalary heterochromatin underreplication in polytene chromosomes results in free double-stranded ends of DNA molecules; ligation of these free ends is the most likely mechanism for ectopic pairing between intercalary heterochromatic and pericentric heterochromatic regions. No support has been found for the view that the frequency of chromosome aberrations is elevated in intercalary heterochromatin.

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“…(I) The behavior of heterochromatic parts is still open to discussion. KAUFMANN and DEMEREC (1937) from their data on break frequencies in Y sperms, have reached the conclusion that there is in all chromosomes including the Y a breakage frequency directly proportional to their metaphase length. From this they further conclude that the chromonema length is directly proportional to metaphase length, as suggested by MULLER and PAINTER (1932); moreover that the Y therefore is of the same general structure as euchromatic chromosomes, and that direct proportionality exists between chromonema length and breakage numbers in all chromosome parts.…”

Section: Discussionmentioning

confidence: 99%

X-Ray Induced Chromosomal Alterations in Drosophila Melanogaster

1938

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N THE fall of 1936 the first two authors began a series of experiments I to determine the frequency of minute inversions in material treated by X-rays. Before long it was realized that the frequency of such inversions is very low and that a reliable analysis would involve such technical difficulties that it would require a great deal more time than was available to the authors. Therefore, the original plan was revised and a new experiment started to determine the relation between X-ray dosage and the frequency of chromosomal breaks, the distribution of breaks along the chromosomes, and related problems. Subsequently when the experimental part of the problem was well under way the third author joined in the work.The first author is responsible for the cytological analysis of the major portion of the female material, the second author was in charge of breeding and X-raying work and helped with the cytological analysis, and the third author is responsible for the cytological analysis of all male material and of a portion of the female data where Swedish-b females were mated with treated Oregon-R males. Permanent preparations of 1765 pairs of salivary glands were used for this study. Slides were prepared by Mr. HERSCHEL ROMAN, Miss RUTH BATE, and Miss EUNICE WHITE, to whom the authors wish to express their appreciation.When this manuscript was ready for press a paper by CATCHESIDE (1938) appeared describing some of his results obtained in experiments identical with ours. Many conclusions reached by CATCHESIDE are identical with our conclusions. MATERIAL AND METHODSThe bulk of the data reported here was obtained from experiments in which inbred Oregon-R wild type stock was used. However, before this experiment was completed a female sterility factor appeared in the stock and to avoid difficulties connected with sterility, females of an inbred Swedish-b wild type line were used in later experiments. In the chart (fig. I) showing the relationship between X-ray dosage and effects, the data from Oregon-R females are presented separately because differences may exist in the genetic constitution of the females used. In analyses of other problems such differences would probably be unimportant and,

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Frequency of Induced Breaks in Chromosomes of Drosophila Melanogaster

Cited by 24 publications

References 4 publications

Evolution in theDrosophila ananassaespecies subgroup

Evolution in theDrosophila ananassaespecies subgroup

Intercalary heterochromatin in polytene chromosomes of Drosophila melanogaster

X-Ray Induced Chromosomal Alterations in Drosophila Melanogaster

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