scholarly journals Genetic background impacts the timing of synaptonemal complex breakdown in Drosophila melanogaster

Chromosoma ◽  
2020 ◽  
Vol 129 (3-4) ◽  
pp. 243-254
Author(s):  
Emily R. Wesley ◽  
R. Scott Hawley ◽  
Katherine Kretovich Billmyre
Keyword(s):  
Drosophila Melanogaster ◽  
Synaptonemal Complex ◽  
Chromosome Segregation ◽  
Structural Component ◽  
Genetic Background ◽  
Important Variable ◽  
Null Mutation ◽  
Control Stock ◽  
Sensitizing Effect ◽  
Meiotic Event

AbstractExperiments performed in different genetic backgrounds occasionally exhibit failure in experimental reproducibility. This is a serious issue in Drosophila where there are no standard control stocks. Here, we illustrate the importance of controlling genetic background by showing that the timing of a major meiotic event, the breakdown of the synaptonemal complex (SC), varies in different genetic backgrounds. We assessed SC breakdown in three different control stocks and found that in one control stock, y w; svspa-pol, the SC broke down earlier than in Oregon-R and w1118 stocks. We further examined SC breakdown in these three control backgrounds with flies heterozygous for a null mutation in c(3)G, which encodes a key structural component of the SC. Flies heterozygous for c(3)G displayed differences in the timing of SC breakdown in different control backgrounds, providing evidence of a sensitizing effect of this mutation. These observations suggest that SC maintenance is associated with the dosage of c(3)G in some backgrounds. Lastly, chromosome segregation was not affected by premature SC breakdown in mid-prophase, consistent with previous findings that chromosome segregation is not dependent on full-length SC in mid-prophase. Thus, genetic background is an important variable to consider with respect to SC behavior during Drosophila meiosis.

scholarly journals THE EFFECTS OF HETEROZYGOSITY CHANGES ON VIABILITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1972 ◽  
Vol 70 (4) ◽  
pp. 595-610
Author(s):  
Ray Moree
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Background ◽  
Laboratory Strain ◽  
Theoretical Expectation ◽  
Wild Type ◽  
Small Deviations ◽  
The Third ◽  
The Difference

ABSTRACT The viability effects of chromosomes from an old and from a new laboratory strain of D. melanogaster were studied in eight factorial combinations and at two heterozygosity levels. The combinations were so constructed that heterozygosity level could be varied in the third chromosomes of the carriers of a homozygous lethal marker, in the third chromosomes of their wild-type segregants, and in the genetic backgrounds of both. Excluding the effect of the marker and the exceptional outcomes of two of the combinations, and taking into account both large and small deviations from theoretical expectation, the following summary is given as the simplest consistent explanation of the results: 1) If total heterozygosities of two segregant types tend toward equality their viabilities tend toward equality also, whether background heterozygosity is high or low; if background heterozygosities is higher the tendency toward equality is slightly greater. 2) If total heterozygosity of two segregant types are unequal the less heterozygous type has the lower viability; the difference is more pronounced when background heterozygosity is low, less when it is high. 3) Differences between segregant viabilities are correlated with differences between the total heterozygosities of the two segregants; genetic background is effective to the extent, and only to the extent, that it contributes to the magnitude of this difference. This in turn appears to underlie, at least partly, the expression of a pronounced interchromosomal epistasis. Thus in this study viability is seen to depend upon both the quantity and distribution of heterozygosity, not only among the chromosomes of an individual but among the individuals of a given combination as well.

scholarly journals Studies of esterase 6 in Drosophila melanogaster: XIV. Variation of esterase 6 levels controlled by unlinked genes in natural populations

1984 ◽  
Vol 43 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Craig S. Tepper ◽  
Anne L. Terry ◽  
James E. Holmes ◽  
Rollin C. Richmond
Keyword(s):  
Drosophila Melanogaster ◽  
Structural Gene ◽  
X Chromosome ◽  
Genetic Background ◽  
Natural Populations ◽  
Regulatory Elements ◽  
Regulatory Locus ◽  
The Third ◽  
Esterase 6 ◽  
Activity Modifiers

SUMMARYThe esterase 6 (Est-6) locus in Drosophila melanogaster is located on the third chromosome and is the structural gene for a carboxylesterase (E.C.3.1.1.1) and is polymorphic for two major electromorphs (slow and fast). Isogenic lines containing X chromosomes extracted from natural populations and substituted into a common genetic background were used to detect unlinked factors that affect the activity of the Est-6 locus. Twofold activity differences of esterase 6 (EST 6) were found among males from these derived lines, which differ only in their X chromosome. These unlinked activity modifiers identify possible regulatory elements. Immunoelectrophoresis was used to estimate quantitatively the levels of specific cross-reacting material in the derived lines. The results show that the variation in activity is due to differences in the amount of EST 6 present. The data are consistent with the hypothesis that there is at least one locus on the X chromosome that regulates the synthesis of EST 6 and that this regulatory locus may be polymorphic in natural populations.

scholarly journals ‘Exceptional sons’ from Drosophila melanogaster mothers carrying a balancer X chromosome

1990 ◽  
Vol 55 (3) ◽  
pp. 159-164 ◽  
Author(s):  
Pierre Hutter
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Early Stage ◽  
Interspecific Crosses ◽  
Hybrid Progeny ◽  
Female Hybrid ◽  
Mitotic Event ◽  
Meiotic Event ◽  
Third Instar Larvae

SummaryThis study reports on exceptional males which are obtained by using Drosophila melanogaster mothers carrying the balancers In(l)FM6 or In(l)FM7 as one of their X chromosomes. The phenomenon was first observed in interspecific crosses between D. melanogaster females and males of its closest relatives which normally produce unisexual female hybrid progeny. Whereas hybrid sons from these crosses die as third instar larvae, the presence of the particular X balancers in the mother allows a low percentage of sons to survive. Similar sterile males are also observed among non- hybrid flies. Data are presented which suggest that the males thus generated could be hyperploid for part of their X chromosome as a result of a meiotic event in their mothers or else they could start life as female zygotes and change sex through a mitotic event at an early stage.

scholarly journals Insights from the reconstitution of the divergent outer kinetochore of Drosophila melanogaster

Open Biology ◽  
2016 ◽  
Vol 6 (2) ◽  
pp. 150236 ◽  
Author(s):  
Yahui Liu ◽  
Arsen Petrovic ◽  
Pascaline Rombaut ◽  
Shyamal Mosalaganti ◽  
Jenny Keller ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Chromosome Segregation ◽  
Functional Organization ◽  
Histone H3 Variant ◽  
Centromeric Protein ◽  
Spindle Microtubules ◽  
Specialized Region ◽  
Structural Methods ◽  
Mitosis And Meiosis ◽  
Shed Light

Accurate chromosome segregation during mitosis and meiosis is crucial for cellular and organismal viability. Kinetochores connect chromosomes with spindle microtubules and are essential for chromosome segregation. These large protein scaffolds emerge from the centromere, a specialized region of the chromosome enriched with the histone H3 variant CENP-A. In most eukaryotes, the kinetochore core consists of the centromere-proximal constitutive centromere-associated network (CCAN), which binds CENP-A and contains 16 subunits, and of the centromere-distal Knl1 complex, Mis12 complex, Ndc80 complex (KMN) network, which binds microtubules and contains 10 subunits. In the fruitfly, Drosophila melanogaster, the kinetochore underwent remarkable simplifications. All CCAN subunits, with the exception of centromeric protein C (CENP-C), and two KMN subunits, Dsn1 and Zwint, cannot be identified in this organism. In addition, two paralogues of the KMN subunit Nnf1 (Nnf1a and Nnf1b) are present. Finally, the Spc105R subunit, homologous to human Knl1/CASC5, underwent considerable sequence changes in comparison with other organisms. We combined biochemical reconstitution with biophysical and structural methods to investigate how these changes reflect on the organization of the Drosophila KMN network. We demonstrate that the Nnf1a and Nnf1b paralogues are subunits of distinct complexes, both of which interact directly with Spc105R and with CENP-C, for the latter of which we identify a binding site on the Mis12 subunit. Our studies shed light on the structural and functional organization of a highly divergent kinetochore particle.

scholarly journals The chromokinesin Klp3a and microtubules facilitate acentric chromosome segregation

2017 ◽  
Vol 216 (6) ◽  
pp. 1597-1608 ◽  
Author(s):  
Travis Karg ◽  
Mary Williard Elting ◽  
Hannah Vicars ◽  
Sophie Dumont ◽  
William Sullivan
Keyword(s):  
Drosophila Melanogaster ◽  
Laser Ablation ◽  
Chromosome Segregation ◽  
Equal Frequency ◽  
Chromosome Fragments ◽  
Underlying Mechanisms

Although poleward segregation of acentric chromosomes is well documented, the underlying mechanisms remain poorly understood. Here, we demonstrate that microtubules play a key role in poleward movement of acentric chromosome fragments generated in Drosophila melanogaster neuroblasts. Acentrics segregate with either telomeres leading or lagging in equal frequency and are preferentially associated with peripheral bundled microtubules. In addition, laser ablation studies demonstrate that segregating acentrics are mechanically associated with microtubules. Finally, we show that successful acentric segregation requires the chromokinesin Klp3a. Reduced Klp3a function results in disorganized interpolar microtubules and shortened spindles. Normally, acentric poleward segregation occurs at the periphery of the spindle in association with interpolar microtubules. In klp3a mutants, acentrics fail to localize and segregate along the peripheral interpolar microtubules and are abnormally positioned in the spindle interior. These studies demonstrate an unsuspected role for interpolar microtubules in driving acentric segregation.

scholarly journals Gene-environment interactions of the eye-gone mutant in Drosophila melanogaster and a comparison with eyeless

1969 ◽  
Vol 13 (3) ◽  
pp. 313-320 ◽  
Author(s):  
David M. Hunt
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Background ◽  
Eye Development ◽  
Deficient Diet ◽  
Developmental Relationship ◽  
Gene Environment ◽  
Mutant Genes

A comparison of the gene-environment interactions of the eyg mutant in two different genetic backgrounds clearly demonstrates that the properties of the genetic background play a major role in the control of the gene-environment interactions of this mutant. Similarly, modifier background is important in the determination of the sensitive stages in eye development to a cholesterol-deficient diet.The phenotypic identity of the eyeless and eye-gone mutants suggests a close underlying metabolic and developmental relationship. Possible inter-relations of these two mutant genes are discussed in the light of their gene-environment interactions in a standardized genotype.

Sign in / Sign up

Export Citation Format

Share Document