scholarly journals A Physical Map of the Polytenized Region (101EF–102F) of Chromosome 4 in Drosophila melanogaster

Genetics ◽  
2000 ◽  
Vol 155 (3) ◽  
pp. 1175-1183
Author(s):  
John Locke ◽  
Lynn Podemski ◽  
Nicole Aippersbach ◽  
Hilary Kemp ◽  
Ross Hodgetts

Abstract Chromosome 4, the smallest autosome (~5 Mb in length) in Drosophila melanogaster contains two major regions. The centromeric domain (~4 Mb) is heterochromatic and consists primarily of short, satellite repeats. The remaining ~1.2 Mb, which constitutes the banded region (101E–102F) on salivary gland polytene chromosomes and contains the identified genes, is the region mapped in this study. Chromosome walking was hindered by the abundance of moderately repeated sequences dispersed along the chromosome, so we used many entry points to recover overlapping cosmid and BAC clones. In situ hybridization of probes from the two ends of the map to polytene chromosomes confirmed that the cloned region had spanned the 101E–102F interval. Our BAC clones comprised three contigs; one gap was positioned distally in 102EF and the other was located proximally at 102B. Twenty-three genes, representing about half of our revised estimate of the total number of genes on chromosome 4, were positioned on the BAC contigs. A minimal tiling set of the clones we have mapped will facilitate both the assembly of the DNA sequence of the chromosome and a functional analysis of its genes.

1977 ◽  
Vol 115 (3) ◽  
pp. 539-563 ◽  
Author(s):  
Paul Szabo ◽  
Robert Elder ◽  
Dale M. Steffensen ◽  
Olke C. Uhlenbeck

1992 ◽  
Vol 60 (2) ◽  
pp. 103-114 ◽  
Author(s):  
Brian Charlesworth ◽  
Angela Lapid ◽  
Darlene Canada

SummaryData were collected on the distribution of nine families of transposable elements among second and third chromosomes isolated from a natural population of Drosophila melanogaster, by means of in situ hybridization of element probes to polytene chromosomes. It was found that the copy numbers per chromosome in the distal sections of the chromosome arms followed a Poisson distribution. Elements appeared to be distributed randomly along the distal sections of the chromosome arms. There was no evidence for linkage disequilibrium in the distal sections of the chromosomes, but some significant disequilibrium was detected in proximal regions. There were many significant correlations between different element families with respect to the identity of the sites that were occupied in the sample. There were also significant correlations between families with respect to sites at which elements achieved relatively high frequencies. Element frequencies per chromosome band were generally low in the distal sections, but were higher proximally. These results are discussed in the light of models of the population dynamics of transposable elements. It is concluded that they provide strong evidence for the operation of a force or forces opposing transpositional increase in copy number. The data suggest that the rate of transposition perelement per generation is of the order of 10−4, for the elements included in this study.


2000 ◽  
Vol 75 (3) ◽  
pp. 275-284 ◽  
Author(s):  
XULIO MASIDE ◽  
STAVROULA ASSIMACOPOULOS ◽  
BRIAN CHARLESWORTH

The rates of movement of 11 families of transposable elements of Drosophila melanogaster were studied by means of in situ hybridization of probes to polytene chromosomes of larvae from a long-term mutation accumulation experiment. Replicate mutation-accumulation lines carrying second chromosomes derived from a single common ancestral chromosome were maintained by backcrosses of single males heterozygous for a balancer chromosome and a wild-type chromosome, and were scored after 116 generations. Twenty-seven transpositions and 1 excision were detected using homozygous viable and fertile second chromosomes, for a total of 235056 potential sources of transposition events and a potential 252880 excision events. The overall transposition rate per element per generation was 1·15×10−4 and the excision rate was 3·95×10−6. The single excision (of a roo element) was due to recombination between the element's long terminal repeats. A survey of the five most active elements among nine homozygous lethal lines revealed no significant difference in the estimates of transposition and excision rates from those from viable lines. The excess of transposition over excision events is in agreement with the results of other in situ hybridization experiments, and supports the conclusion that replicative increase in transposable element copy number is opposed by selection. These conclusions are compared with those from other studies, and with the conclusions from population surveys of element frequencies.


1984 ◽  
Vol 4 (5) ◽  
pp. 387-396 ◽  
Author(s):  
Carmen Arribas ◽  
Marta Izquierdo

We have studied the presence of a cloned fragment of DNA from Drosophila melanogaster in other organisms by means of nucleic acid hybridization analysis. The isolated region is localized in polytene chromosomes at the 63F subdivision. This region includes a puff that responds within minutes to ecdysone stimulation. We have found that 63F DNA from D. melanogaster hybridizes ‘in situ’ to both DNA and RNA from D. simulans, D. teissieri, and D. hydei. In all these species the isolated DNA remains associated with one early-ecdysone stimulated puff. The isolated Drosophila recombinant DNA is also complementary to polyadenylated RNA from foetal and adult rat liver but fails to hybridize to the nonpolyadenylated RNA classes from both sources and to polyadenylated RNA from rat mammary glands.


2020 ◽  
Author(s):  
Francisco García-Franco ◽  
Lilian Barandica-Cañon ◽  
Ezel Galindo-Pérez ◽  
Martha Martínez García ◽  
Blanca Chávez-Sandoval

Abstract Here, we present for the first time, a method to generate homozygous segmental introgressions, by means of crosses between a pair of synmorphic species. The introgressions were monitored by the cytogenetic method of polygenic chromosome asynapses. Later the introgressions were evaluated in their capacity to produce sterility in segmental males. Also, the smallest segment with the capacity to produce sterility in segmental males was mapped by in situ hybridization of polythene chromosomes, using 8 sequences of BACs clones as probes. Finally, a bioinformatic analysis was carried out to identify the presence of particular genes. From 2 parental strains, D. buzzatii and D. koepferae, 6 simple segmental hybrid lines were generated, whose introgressing segments are distributed along chromosome 4 of these species. From the 6 simple segmental lines and by means of a new crossing strategy, the 6 respective homozygous segmental hybrid offspring were obtained, each of them carrying a specific homozygous introgression. None of the 6 heterozygous introgressions was capable of producing sterility in segmental males, while 4 of the same homozygous introgressions produced total sterility in segmental males, including in this group the two smallest introgressive segments, one of 5.03 % and the other 7.87% with respect to the total length of chromosome 4, which are located in the region F2 to F4 of the standard cytological map based on polythene chromosomes of the Drosophila Repleta group. In situ hybridization, using 8 clones from contig 1065 located along the F2 to F4 region of the physical map of D. buzzattii constructed in BACs, confirmed the precise location of the 6 clones in the chromosomal region F2 to F4 of chromosome 4 of the polygenic chromosomes of both D. buzzatii and D. mojavensis. The bioinformatic analysis of the F2 to F4 region, using the complete genetic sequence of the contig 1065 of D. buzzatti shows the presence of two predicted genes in the genomic map of D. buzzatii (g.1313.t1 and g.1314.t1), and the orthologous association of these 2 genes both with the D. moj_GI22766 gene of D. mojavensis and with the Trivet gene of D. melanogaster.


Genetics ◽  
1995 ◽  
Vol 139 (4) ◽  
pp. 1631-1647 ◽  
Author(s):  
E Madueño ◽  
G Papagiannakis ◽  
G Rimmington ◽  
R D Saunders ◽  
C Savakis ◽  
...  

Abstract A physical map of the euchromatic X chromosome of Drosophila melanogaster has been constructed by assembling contiguous arrays of cosmids that were selected by screening a library with DNA isolated from microamplified chromosomal divisions. This map, consisting of 893 cosmids, covers approximately 64% of the euchromatic part of the chromosome. In addition, 568 sequence tagged sites (STS), in aggregate representing 120 kb of sequenced DNA, were derived from selected cosmids. Most of these STSs, spaced at an average distance of approximately 35 kb along the euchromatic region of the chromosome, represent DNA tags that can be used as entry points to the fruitfly genome. Furthermore, 42 genes have been placed on the physical map, either through the hybridization of specific probes to the cosmids or through the fact that they were represented among the STSs. These provide a link between the physical and the genetic maps of D. melanogaster. Nine novel genes have been tentatively identified in Drosophila on the basis of matches between STS sequences and sequences from other species.


Genome ◽  
1987 ◽  
Vol 29 (1) ◽  
pp. 72-75 ◽  
Author(s):  
D. G. Bedo ◽  
A. J. Howells

The white gene of Lucilia cuprina was mapped to trichogen polytene chromosomes using in situ hybridization. A tritium-labelled riboprobe made from the first gene cloned from this species was used with techniques modified from standard methods used for Drosophila melanogaster. Cytological data limiting the location of the white gene to a small portion of 3L and complementing the in situ results are also presented. Key words: Lucilia cuprina, white gene, in situ hybridization.


1981 ◽  
Vol 37 (2) ◽  
pp. 209-214 ◽  
Author(s):  
W. J. Peacock ◽  
R. Appels ◽  
S. Endow ◽  
D. Glover

SUMMARYThe major type I insert sequence for the 28S rRNA genes of Drosophila melanogaster has been mapped within the chromosomes using a probe synthesized from a cloned sequence containing the entire 5·4 kb segment. The genomic distribution was shown to be complex in that the insert sequence occurred next to many different types of sequences, in addition to occurring as an insert in the 28S rRNA genes of the X chromosome. In situ hybridization of mitotic chromosomes showed most of the insert units not contained in the ribosomal genes to be located near the ribosomal gene cluster on the X chromosome. Additional sites were detected in polytene chromosomes in region 102C, 8–12 and in the hetero-chromatin of the autosomes.


Genetics ◽  
2000 ◽  
Vol 156 (4) ◽  
pp. 1797-1816 ◽  
Author(s):  
Hafid Laayouni ◽  
Mauro Santos ◽  
Antonio Fontdevila

Abstract We present a physical map based on RAPD polymorphic fragments and sequence-tagged sites (STSs) for the repleta group species Drosophila buzzatii. One hundred forty-four RAPD markers have been used as probes for in situ hybridization to the polytene chromosomes, and positive results allowing the precise localization of 108 RAPDs were obtained. Of these, 73 behave as effectively unique markers for physical map construction, and in 9 additional cases the probes gave two hybridization signals, each on a different chromosome. Most markers (68%) are located on chromosomes 2 and 4, which partially agree with previous estimates on the distribution of genetic variation over chromosomes. One RAPD maps close to the proximal breakpoint of inversion 2z3 but is not included within the inverted fragment. However, it was possible to conclude from this RAPD that the distal breakpoint of 2z3 had previously been wrongly assigned. A total of 39 cytologically mapped RAPDs were converted to STSs and yielded an aggregate sequence of 28,431 bp. Thirty-six RAPDs (25%) did not produce any detectable hybridization signal, and we obtained the DNA sequence from three of them. Further prospects toward obtaining a more developed genetic map than the one currently available for D. buzzatii are discussed.


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