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Gene conversion is the nonreciprocal transfer of information from one DNA duplex to another; in meiosis, it is frequently associated with crossing-over. We review the genetic properties of meiotic recombination and previous models of conversion and crossing-over. In these models, recombination is initiated by single-strand nicks, and heteroduplex DNA is(More)
Precise DNA replication is crucial for genome maintenance, yet this process has been inherently difficult to study on a genome-wide level in untransformed differentiated metazoan cells. To determine how metazoan DNA replication can be repressed, we examined regions selectively under-replicated in Drosophila polytene salivary glands, and found they are(More)
To gain insight into how genomic information is translated into cellular and developmental programs, the Drosophila model organism Encyclopedia of DNA Elements (modENCODE) project is comprehensively mapping transcripts, histone modifications, chromosomal proteins, transcription factors, replication proteins and intermediates, and nucleosome properties(More)
Chorion gene amplification in the ovaries of Drosophila melanogaster is a powerful system for the study of metazoan DNA replication in vivo. Using a combination of high-resolution confocal and deconvolution microscopy and quantitative realtime PCR, we found that initiation and elongation occur during separate developmental stages, thus permitting analysis(More)
Mutations in the Drosophila mei-S332 gene cause premature separation of the sister chromatids in late anaphase of meiosis I. Therefore, the mei-S332 protein was postulated to hold the centromere regions of sister chromatids together until anaphase II. The mei-S332 gene encodes a novel 44 kDa protein. Mutations in mei-S332 that differentially affect function(More)
Polyploid or polytene cells, which have more than 2C DNA content, are widespread throughout nature and present in most differentiated Drosophila tissues. These cells also can display differential replication, that is, genomic regions of increased or decreased DNA copy number relative to overall genomic ploidy. How frequently differential replication is used(More)
The process of polytenization plays a crucial role in Drosophila development, and most of the larval tissues are polytene. By analyzing the pattern of DNA replication in embryos pulse-labeled with BrdU, we show that many larval tissues undergo a transition to begin becoming polytene late in embryogenesis. Our results demonstrate that in these larval tissues(More)
Mutations in the Drosophila maternal genes plutonium (plu) and pan gu (png) have the striking phenotype that DNA replication initiates in unfertilized eggs. Fertilized eggs from plu or png mutant mothers also have a mutant phenotype; DNA replication is uncoupled from nuclear division, resulting in giant, polyploid nuclei. Analysis of multiple alleles of(More)
In metazoan oocytes, a metaphase arrest coordinates the completion of meiosis with fertilization. Vertebrate mos maintains the metaphase II arrest of mature oocytes and prevents DNA replication between the meiotic divisions. We identified a Drosophila homolog of mos and showed it to be the mos ortholog by two additional criteria. The dmos transcripts are(More)