scholarly journals RECOMBINATION AT THE BAR LOCUS IN AN INVERTED ATTACHED-X SYSTEM IN DROSOPHILA MELANOGASTER

Genetics ◽  
1973 ◽  
Vol 75 (3) ◽  
pp. 485-495
Author(s):  
Susan J Gabay ◽  
John R Laughnan
Keyword(s):  
Drosophila Melanogaster ◽  
Marker Genes ◽  
Event Analysis ◽  
Chromatid Break ◽  
Valid Test

ABSTRACT Recombination at the Bar locus in Drosophila melanogaster was investigated in an inverted attached-X system which enhanced the frequency of homozygosis for the Bar region. Females among the progeny of homozygous B mothers were searched for changes of B to BB and to B+. Marker genes were followed and exceptional half-tetrads were analyzed in regard to two hypotheses: that of exchange between obliquely synapsed members of the duplication, which is associated with exchange of outside markers, and that of intrachromosomal exchange, which does not involve recombination of markers.—Recombinant exceptions of B+ /BB genotype, carrying the outside marker combinations predicted on the hypothesis of exchange between obliquely synapsed duplication members, were encountered repeatedly. It is established that B+ and BB strands are reciprocal products of the same event.—Twelve nonrecombinant exceptional strands were isolated; ten of these were B+ and two were BB. Only one of the nonrecombinant half-tetrads offered the opportunity to test the prediction of reciprocity of the intrachromosomal event. Analysis showed the exceptional female to be of the constitution BB/B, a type not expected on the hypothesis. While it could have arisen through some kind of copy error in the repair of a chromatid break, a valid test of the hypothesis of intrachromosomal exchange must rest on the isolation and analysis of more cases of the appropriate exceptional genotype.—In several cases Bar changes were found to be associated with aberrations; all but one of these involved spontaneous, cytologically identifiable deletions.

scholarly journals Regular responses to selection 3. Interaction between located polygenes

1966 ◽  
Vol 7 (1) ◽  
pp. 96-121 ◽  
Author(s):  
S. G. Spickett ◽  
J. M. Thoday
Keyword(s):  
Drosophila Melanogaster ◽  
Linkage Group ◽  
Genetic Variance ◽  
Directional Selection ◽  
Marker Genes ◽  
Linkage Groups ◽  
Developmental Effects ◽  
Number Lines ◽  
Individual Effects ◽  
Chromosome Ii

1. This paper describes further investigations of the high sternopleural chaeta-number lines of Drosophila melanogaster established by directional selection by Thoday & Boam (Genet. Res. 2, 161). The lines are vg 4 with a mean of 35·6 and vg 6 with a mean of 39·2 chaetae per fly.2. Two locatable polygenes, 3a and 3b, distinguish the line third chromosomes from those of Oregon inbred (mean about 20·5, an ancestor of all the lines). These two genes are both located between the markers h and eyg and do not interact.3. There is one locatable polygene at 41·1 ± 1·7 centiMorgans distinguishing the line second chromosomes from those of Oregon. There is no evidence that this gene is a linked complex, and, if it be a linked complex, it is unlikely to occupy more than 2 map units of the second linkage group. It interacts strongly and positively with the gene 3a.4. These three genes account for 80% of the genetic variance of the vg 4 × Oregon F2.5. Two separate regions at 2·4 ± 0·5 and 50·5 ± 0·9 centiMorgans distinguish the vg 6 × chromosome from that of Oregon. They do not appear to interact. Together they interact strongly and positively with gene 3a.6. These five genes account for 87·5% of the chaeta-number difference between vg 6 and Oregon.7. The locatable polygenes on chromosomes II and III each have qualitatively distinguishable developmental effects.8. It is pointed out that, though the genetics of these lines may be unusually simple, the results indicate that attempts to locate specific genes and study their individual effects should be made more often by students of continuous variation. Since the location of the polygene in chromosome II was done using marker genes 45 map units apart, such studies may be practicable even in species whose linkage groups are much less well marked than those of Drosophila melanogaster.

scholarly journals Rescue from the abnormal oocyte maternal-effect lethality by ABO heterochromatin in Drosophila melanogaster.

Genetics ◽  
1991 ◽  
Vol 128 (3) ◽  
pp. 583-594 ◽  
Author(s):  
J Tomkiel ◽  
S Pimpinelli ◽  
L Sandler
Keyword(s):  
Drosophila Melanogaster ◽  
Maternal Effect ◽  
Sex Chromosome ◽  
Event Analysis ◽  
Vital Function ◽  
Early Cleavage ◽  
Maternal Genome ◽  
Loss Event ◽  
Temporal And Spatial ◽  
Fertilized Egg

Abstract The euchromatic maternal-effect mutation abnormal oocyte (abo), of Drosophila melanogaster interacts with regions of heterochromatin known as ABO, which reside on the X, Y and second chromosomes. Here, we show that survival of progeny from abo females depends in part upon the maternal dosage of ABO heterochromatin. A comparison was made of the recovery of genotypically identical progeny from abo mothers bearing sex chromosomes of various ABO contents. The results show that the recovery of daughters was decreased if mothers were ABO-/ABO-. However, no decrease was observed if mothers were ABO+/ABO-. In addition, the survival of daughters was greater when they received an ABO-X chromosome from an ABO-/ABO+ mother rather than the father. We suggest that these results reflect a complementation or interaction between the ABO-deficient X and the ABO heterochromatin in the maternal genome. This proposed interaction could occur early in oogenesis in the mother or prior to completion of meiosis I in the fertilized egg. To determine if zygotic dosage of ABO heterochromatin might also be important at very early stages of embryogenesis, we examined the timing of zygotic rescue by paternally donated ABO heterochromatin using a second mutation, paternal loss (pal). Homozygous pal males produce progeny which lose paternally derived chromosomes during the early zygotic divisions. Zygotes that have lost a paternal sex chromosome in a fraction of their nuclei will be mosaic for the amount of ABO heterochromatin. By monitoring the recovery of pal-induced mosaics from abo and abo+ females, we could determine the temporal and spatial requirements for ABO function. Results show that the survival of progeny from the abo maternal-effect lethality was increased if ABO heterochromatin was present prior to the pal-induced loss event. Analysis of mosaic patterns did not reveal a specific lethal focus. We conclude from these results that ABO heterochromatin serves its vital function prior to completion of the early cleavage divisions in progeny of abo mothers.

Author response for "Location and arrangement of campaniform sensilla in Drosophila melanogaster"

2020 ◽  
Author(s):  
Gesa F. Dinges ◽  
Alexander S. Chockley ◽  
Till Bockemühl ◽  
Kei Ito ◽  
Alexander Blanke ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Author Response ◽  
Campaniform Sensilla

Live Confocal Analysis of Fertilization and Early Development

2001 ◽  
Vol 7 (S2) ◽  
pp. 1012-1013
Author(s):  
Uyen Tram ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Embryonic Development ◽  
Real Time ◽  
Early Development ◽  
Fluorescent Probes ◽  
Primary Defect ◽  
Fluorescent Analysis ◽  
Dynamic Event ◽  
Enormous Amount ◽  
Fluorescent Studies

Embryonic development is a dynamic event and is best studied in live animals in real time. Much of our knowledge of the early events of embryogenesis, however, comes from immunofluourescent analysis of fixed embryos. While these studies provide an enormous amount of information about the organization of different structures during development, they can give only a static glimpse of a very dynamic event. More recently real-time fluorescent studies of living embryos have become much more routine and have given new insights to how different structures and organelles (chromosomes, centrosomes, cytoskeleton, etc.) are coordinately regulated. This is in large part due to the development of commercially available fluorescent probes, GFP technology, and newly developed sensitive fluorescent microscopes. For example, live confocal fluorescent analysis proved essential in determining the primary defect in mutations that disrupt early nuclear divisions in Drosophila melanogaster. For organisms in which GPF transgenics is not available, fluorescent probes that label DNA, microtubules, and actin are available for microinjection.

Apoptosis and development

2003 ◽  
Vol 39 ◽  
pp. 11-24 ◽  
Author(s):  
Justin V McCarthy
Keyword(s):  
Drosophila Melanogaster ◽  
Mammalian Cells ◽  
Cell Number ◽  
Model Organisms ◽  
Biological Processes ◽  
Nematode Caenorhabditis Elegans ◽  
Apoptotic Pathway ◽  
Genetic Pathways ◽  
Evolutionarily Conserved ◽  
Multicellular Organisms

Apoptosis is an evolutionarily conserved process used by multicellular organisms to developmentally regulate cell number or to eliminate cells that are potentially detrimental to the organism. The large diversity of regulators of apoptosis in mammalian cells and their numerous interactions complicate the analysis of their individual functions, particularly in development. The remarkable conservation of apoptotic mechanisms across species has allowed the genetic pathways of apoptosis determined in lower species, such as the nematode Caenorhabditis elegans and the fruitfly Drosophila melanogaster, to act as models for understanding the biology of apoptosis in mammalian cells. Though many components of the apoptotic pathway are conserved between species, the use of additional model organisms has revealed several important differences and supports the use of model organisms in deciphering complex biological processes such as apoptosis.

Insights into amyloid disease from fly models

2014 ◽  
Vol 56 ◽  
pp. 69-83 ◽  
Author(s):  
Ko-Fan Chen ◽  
Damian C. Crowther
Keyword(s):  
Drosophila Melanogaster ◽  
Neurodegenerative Disorders ◽  
Amyloid Β ◽  
Amyloid Β Peptide ◽  
Disease Pathogenesis ◽  
Amyloid Aggregates ◽  
Aβ Amyloid ◽  
Polypeptide Chains ◽  
Amyloid Diseases

The formation of amyloid aggregates is a feature of most, if not all, polypeptide chains. In vivo modelling of this process has been undertaken in the fruitfly Drosophila melanogaster with remarkable success. Models of both neurological and systemic amyloid diseases have been generated and have informed our understanding of disease pathogenesis in two main ways. First, the toxic amyloid species have been at least partially characterized, for example in the case of the Aβ (amyloid β-peptide) associated with Alzheimer's disease. Secondly, the genetic underpinning of model disease-linked phenotypes has been characterized for a number of neurodegenerative disorders. The current challenge is to integrate our understanding of disease-linked processes in the fly with our growing knowledge of human disease, for the benefit of patients.

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