scholarly journals NONESSENTIAL SEQUENCES, GENES, AND THE POLYTENE CHROMOSOME BANDS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 88 (4) ◽  
pp. 723-742 ◽  
Author(s):  
Michael W Young ◽  
B H Judd
Keyword(s):  
Drosophila Melanogaster ◽  
Polytene Chromosome ◽  
X Chromosome ◽  
Observable Effect ◽  
Phenotypic Changes ◽  
Complementation Groups ◽  
One To One ◽  
Functional Units ◽  
Chromosomal Sequences ◽  
Chromosome Bands

ABSTRACT From earlier work, there appears to be an underlying one-to-one correspondence of polytene chromosome bands and complementation groups within a sizeable, continuous X-chromosome segment, 3A1-3C7 (Judd, Shen and Kaufman 1972; Lefevre and Green 1972). However, most of the data supporting this one-to-one relation of bands and genes were gathered from mutants that upset vital functional units, thus leading to lethality. Among this series of mutants, only four loci, zeste, white, roughest and verticals, have no known lethal alleles. If phenotypic changes less drastic than lethality result from the loss of other chromosomal segments, they probably would not have been recognized in the earlier studies.—We report here some chromosomal sequences localized in 3A, 3B, and 3C whose loss effects no lethal change in the development of the animal. A portion of the 3A3-3A4 region can be disrupted in a nonlethal fashion, yet this sequence does not seem to be a part of either the zeste locus or l(1)zw1, which are known to be located in these bands. Two more complementation groups have been discovered that have no lethal alleles and map to 3B4-3B6; a third falls within 3B1-2. The loss of a sequence in 3C2-3 is tolerated without any genetically observable effect. Between 3C7 and the boundary of 3D there is at least one more sequence that behaves in this manner.—The discovery of these units, which are not allelic to any of the loci previously known, makes it clear that division 3B contains more genes (i.e., complementation groups) than polytene chromosome bands, while portions of 3A and 3C seem to have no functional significance. Accordingly many polytene chromosome bands may be composites of several complementing functional units. This investigation also indicates that there are chromosomal segments that are seemingly dispensible and thus function in a manner that is difficult or impossible to define with available methods.

scholarly journals CYTOGENETIC ANALYSIS OF THE CHROMOSOMAL REGION IMMEDIATELY ADJACENT TO THE ROSY LOCUS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1980 ◽  
Vol 95 (1) ◽  
pp. 95-110 ◽  
Author(s):  
Arthur J Hilliker ◽  
Stephen H Clark ◽  
Arthur Chovnick ◽  
William M Gelbart
Keyword(s):  
Drosophila Melanogaster ◽  
Polytene Chromosome ◽  
Structural Information ◽  
Genetic Regulation ◽  
Chromosome Band ◽  
Genetic Dissection ◽  
Genetic Unit ◽  
Complementation Groups ◽  
The Relationship ◽  
Chromosome Bands

ABSTRACT This report describes the genetic analysis of a region of the third chromosome of Drosophila melanogaster extending from 87D2-4 to 87E12-F1, an interval of 23 or 24 polytene chromosome bands. This region includes the rosy (ry, 3-52.0) locus, carrying the structural information for xanthine dehydrogenase (XDH). We have, in recent years, focused attention on the genetic regulation of the rosy locus and, therefore, wished to ascertain in detail the immediate genetic environmcnt of this locus. Specifically, we question if rosy is a solitary genetic unit or part of a larger complex genetic unit encompassing adjacent genes. Our data also provide opportunity to examine further the relationship between euchromatic gene distrihution and polytene chromosome structure.—The results of our genetic dissection of the rosy microregion substantiate the conclusion drawn earlier (SCHALET, KERNAGHAN and CHOVNICK 1964) that the rosy locus is the only gene in this region concerned with XDH activity and that all adjacent genetic units are functionally, as well as spatially, distinct Erom the rosy gene. Within the rosy micro-region, we observed a close correspondence between the number of complementation groups (21) and the number of polytene chromosome bands (23 or 24). Consideration of this latter observation in conjunction with those of similar studies of other chhromosomal regions supports the hypothesis that each polytene chromosome band corresponds to a single genetic unit.

scholarly journals Genetic and developmental analysis of polytene section 17 of the X chromosome of Drosophila melanogaster.

Genetics ◽  
1992 ◽  
Vol 130 (3) ◽  
pp. 569-583
Author(s):  
D F Eberl ◽  
L A Perkins ◽  
M Engelstein ◽  
A J Hilliker ◽  
N Perrimon
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Developmentally Regulated ◽  
Present Evidence ◽  
Lethal Mutations ◽  
Sterile Technique ◽  
Dominant Female ◽  
Complementation Groups ◽  
Developmental Analysis ◽  
Chromosome Bands

Abstract Polytene section 17 of the X chromosome of Drosophila melanogaster, previously known to contain six putative lethal complementation groups important in oogenesis and embryogenesis, has here been further characterized genetically and developmentally. We constructed fcl+Y, a duplication of this region, which allowed us to conduct mutagenesis screens specific for the region and to perform complementation analyses (previously not possible). We recovered 67 new lethal mutations which defined 15 complementation groups within Df(1)N19 which deletes most of polytene section 17. The zygotic lethal phenotypes of these and preexisting mutations within polytene section 17 were examined, and their maternal requirements were analysed in homozygous germline clones using the dominant female sterile technique. We present evidence that an additional gene, which produces two developmentally regulated transcripts, is located in this region and is involved in embryogenesis, although no mutations in this gene were identified. In this interval of 37 to 43 polytene chromosome bands we have defined 17 genes, 12 (71%) of which are of significance to oogenesis or embryogenesis.

Genetic instability in Drosophila melanogaster mediated by hobo transposable elements.

Genetics ◽  
1993 ◽  
Vol 133 (2) ◽  
pp. 315-334
Author(s):  
F Sheen ◽  
J K Lim ◽  
M J Simmons
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
X Chromosome ◽  
Molecular Techniques ◽  
F Region ◽  
Hobo Element ◽  
Complementation Groups ◽  
Derivatives Of ◽  
Chromosome Bands

Abstract Eight independent recessive lethal mutations that occurred on derivatives of an unstable X chromosome (Uc) in Drosophila melanogaster were analyzed by a combination of genetic and molecular techniques. Seven of the mutations were localized to complementation groups in polytene chromosome bands 6E; 7A. In situ hybridization and genomic Southern analysis established that hobo transposable elements were associated with all seven of the mutations. Six mutations involved deletions of DNA, some of which were large enough to be seen cytologically, and in each case, a hobo element was inserted at the junction of the deletion's breakpoints. A seventh mutation was associated with a small inversion between 6F and 7A-B and a hobo element was inserted at one of its breakpoints. One of the mutant chromosomes had an active hobo-mediated instability, manifested by the recurrent production of mutations of the carmine (cm) locus in bands 6E5-6. This instability persisted for many generations in several sublines of an inbred stock. Two levels of instability, high and basal, were distinguished. Sublines with high instability had two hobo elements in the 6E-F region and produced cm mutations by deleting the segment between the two hobos; a single hobo element remained at the junction of the deletion breakpoints. Sublines with low instability had only one hobo element in the 6E-F region, but they also produced deletion mutations of cm. Both types of sublines also acquired hobo-mediated inversions on the X chromosome. Collectively, these results suggest that interactions between hobo elements are responsible for the instability of Uc. It is proposed that interactions between widely separated elements produce gross rearrangements that restructure the chromosome and that interactions between nearby elements cause regional instabilities manifested by the recurrence of specific mutations. These regional instabilities may arise when a copy of hobo transposes a short distance, creating a pair of hobos that can interact to produce small rearrangements.

scholarly journals Developmental genetics of loci at the base of the X chromosome of Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 121 (2) ◽  
pp. 313-331 ◽  
Author(s):  
N Perrimon ◽  
D Smouse ◽  
G L Miklos
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Developmental Genetics ◽  
Optic Lobes ◽  
Sterile Technique ◽  
Specific Subset ◽  
Dominant Female ◽  
Clone Analysis ◽  
Complementation Groups ◽  
Developmental Analysis

Abstract We have conducted a genetic and developmental analysis of the 26 contiguous genetic complementation groups within the 19D3-20F2 interval of the base of the X chromosome, a region of 34 polytene bands delimited by the maroon-like and suppressor of forked loci. Within this region there are four loci which cause visible phenotypes but which have little or no effect on zygotic viability (maroon-like, little fly, small optic lobes and sluggish). There are 22 loci which, when mutated, are zygotic lethals and three of these, legless/runt, folded gastrulation and 13E3, have severe effects on embryonic development. In addition, three visible phenotypes have been defined only by overlapping deficiencies (melanized-like, tumorous head, and varied outspread). We have analyzed the lethal phases and maternal requirement of 58 mutations at 22 of the zygotic lethal loci by means of germline clone analysis using the dominant female sterile technique. Additionally, all lethal complementation groups, as well as a specific subset of deficiencies, have been studied histologically for defects in the development of the central and peripheral embryonic nervous systems.

THE ANATOMY AND FUNCTION OF A SEGMENT OF THE X CHROMOSOME OF DROSOPHILA MELANOGASTER

Genetics ◽  
1972 ◽  
Vol 71 (1) ◽  
pp. 139-156
Author(s):  
B H Judd ◽  
M W Shen ◽  
T C Kaufman
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Functional Group ◽  
Deletion Mapping ◽  
Mutant Type ◽  
Functional Units ◽  
Average Size ◽  
And Function

ABSTRACT An average size chromomere of the polytene X chromosome of Drosophila melanogaster contains enough DNA in each haploid equivalent strand to code for 30 genes, each 1,000 nucleotides long. We have attempted to learn about the organization of chromosomes by asking how many functional units can be localized within a chromomere. This was done by 1) recovery of mutants representative of every cistron in the 3A2-3C2 region; 2) the characterization of the function of each mutant type and grouping by complementation tests; 3) the determination of the genetic and cytological position of each cistron by recombination and deletion mapping. The data clearly show one functional group per chromomere. It is postulated that a chromomere is one cistron within which much of the DNA is regulatory in function.

scholarly journals LETHALITY PATTERNS AND MORPHOLOGY OF SELECTED LETHAL AND SEMI-LETHAL MUTATIONS IN THE ZESTE-WHITE REGION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1972 ◽  
Vol 72 (4) ◽  
pp. 615-638 ◽  
Author(s):  
M P Shannon ◽  
T C Kaufman ◽  
M W Shen ◽  
B H Judd
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
X Chromosome ◽  
Pattern Analysis ◽  
Salivary Gland Chromosome ◽  
Developmental Genetics ◽  
Morphological Attributes ◽  
White Region ◽  
Lethal Mutations ◽  
Complementation Groups

ABSTRACT Aspects of the developmental genetics of lethal and semi-lethal mutants representing 13 complementation groups (cistrons) in the 3A-3C region of the X chromosome of Drosophila melanogaster are given. Each of these cistrons is associated with a particular chromomere in the salivary gland chromosome. Mutants within each cistron have similar lethality patterns and morphological attributes, and the characteristics of a given cistron are distinct with respect to other cistrons. These results provide additional evidence that only one function is associated with each chromomere.—The results of the lethality pattern analysis are also compared with previous studies of lethal mutants of Drosophila.

scholarly journals GENETIC CHARACTERIZATION OF THE REGION BETWEEN 86F1,2 AND 87B15 ON CHROMOSOME 3 OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 98 (4) ◽  
pp. 775-789
Author(s):  
J Gausz ◽  
H Gyurkovics ◽  
G Bencze ◽  
A A M Awad ◽  
J J Holden ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Heat Shock ◽  
Genetic Characterization ◽  
Chromosome 3 ◽  
Gene Encoding ◽  
Lethal Mutations ◽  
Complementation Groups ◽  
Shock Locus ◽  
Chromosome Bands

ABSTRACT The region between 86F1,2 and 87B15 on chromosome 3 of Drosophila melanogaster, which contains about 27 polytene chromosome bands including the 87A7 heat-shock locus, has been screened for EMS-induced visible and lethal mutations. We have recovered 268 lethal mutations that fall into 25 complementation groups. Cytogenetic localization of the complementation groups by deficiency mapping is consistent with the notion that each band encodes a single genetic function. We have also screened for mutations at the 87A7 heat shock locus, using a chromosome that has only one copy of the gene encoding the 70,000 dalton heat-shock protein (hsp70). No lethal or visible mutations at 87A7 were identified from 10,719 mutagenized chromosomes, and no female-sterile mutations at 87A7 were recovered from the 1,520 chromosomes whose progeny were tested for female fertility. We found no evidence that a functional hsp70 gene is required for development under laboratory conditions.

scholarly journals HYPOMORPHIC LETHAL MUTATIONS AND THEIR IMPLICATIONS FOR THE INTERPRETATION OF LETHAL COMPLEMENTATION STUDIES IN DROSOPHILA

Genetics ◽  
1983 ◽  
Vol 105 (4) ◽  
pp. 957-968
Author(s):  
David Nash ◽  
Frank C Janca
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Small Region ◽  
Essential Genes ◽  
Activity Levels ◽  
Lethal Mutations ◽  
Homozygous Mutant ◽  
Complementation Groups ◽  
Interallelic Complementation ◽  
Hypomorphic Alleles

ABSTRACT In a small region of the X chromosome of Drosophila melanogaster, we have found that a third of the mutations that appear to act as lethals in segmental haploids are viable in homozygous mutant individuals. These viable mutations fall into four complementation groups. The most reasonable explanation of these mutations is that they are a subset of functionally hypomorphic alleles of essential genes: hypomorphic mutations with activity levels above a threshold required for survival, but below twice that level, should behave in this manner. We refer to these mutations as "haplo-specific lethal mutations." In studies of autosomal lethals, haplo-specific lethal mutations can be included in lethal complementation tests without being identified as such. Accidental inclusion of disguised haplo-specific lethals in autosomal complementation tests will generate spurious examples of interallelic complementation.

scholarly journals Genetic analysis of the brahma gene of Drosophila melanogaster and polytene chromosome subdivisions 72AB.

Genetics ◽  
1994 ◽  
Vol 137 (3) ◽  
pp. 803-813 ◽  
Author(s):  
B J Brizuela ◽  
L Elfring ◽  
J Ballard ◽  
J W Tamkun ◽  
J A Kennison
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Polytene Chromosome ◽  
Single Gene ◽  
Homeotic Genes ◽  
Catalytic Subunits ◽  
Gtp Binding ◽  
Dependent Protein ◽  
Complementation Groups ◽  
Interallelic Complementation

Abstract The brahma gene is required for activation of the homeotic genes of the Antennapedia and bithorax complexes in Drosophila. We have isolated and characterized 21 mutations in brahma. We show that both maternal and zygotic functions of brahma are required during embryogenesis. In addition, the severe abnormalities caused by loss of maternal brahma expression show that the homeotic genes are not the only targets for brahma activation. The complex pattern of interallelic complementation for the 21 brahma alleles suggests that brahama may act as a multimer. In addition to mutations in brahma, we have isolated mutations in four other essential genes within polytene chromosome subdivisions 72AB. Based on a compilation of similar studies that include about 24% of the genome, we estimate that about 3600 genes in Drosophila can mutate to cause recessive lethality, with fewer than 900 additional genes essential only for gametogenesis. We have identified three times more transcripts than lethal complementation groups in 72AB. One transcript in 72AB is the product of the essential arf-like gene and encodes a member of the ARF subfamily of small GTP-binding proteins. Two other transcripts are probably the products of a single gene whose protein products are similar to the catalytic subunits of cAMP-dependent protein kinases.

scholarly journals VIABILITY OF HOMOZYGOUS DEFICIENCIES IN SOMATIC CELLS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1979 ◽  
Vol 91 (3) ◽  
pp. 443-453
Author(s):  
Pedro Ripoll ◽  
A García-Bellido
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Survival ◽  
Polytene Chromosome ◽  
Somatic Cells ◽  
Mitotic Recombination ◽  
Chromosome Bands

ABSTRACT The viability of cells made homozygous for different deficiencies by induced mitotic recombination was examined. The deficiencies varied in length from two to 30 polytene chromosome bands and were distributed over the five major chromosome arms. Among a sample of 30, ten deficiencies were cell viable. Our results show that 12% of the genome is necessary for cell survival, supporting previous estimates of about 5,000 genes in the genome of Drosophila.

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