scholarly journals Studies on metatherian sex chromosomes. XII. Sex-linked inheritance and probable paternal X-inactivation of a-galactosidase A in Australian marsupials.

1983 ◽  
Vol 36 (6) ◽  
pp. 511 ◽  
Author(s):  
DW Cooper ◽  
PA Woolley ◽  
GM Maynes ◽  
FS Sherman ◽  
WE Poole
Keyword(s):  
Genetic Variation ◽  
Electrophoretic Mobility ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Phylogenetic Relationships ◽  
X Inactivation ◽  
Mobility Data

An investigation of genetic variation in the electrophoretic mobility of the enzyme a-galactosidase A (EC 3.2.1.22) has been carried out for 33 species of Australian metatherian (marsupial) mammals. The results are compatible with the enzyme being sex-linked in macropodids (kangaroos and wallabies) and probably in dasyurids (marsupial 'mice', etc.), as it is in eutherian (placental) mammals. The results also suggest that the mode of dosage compensation for this locus is the same as for other sexlinked loci in kangaroos, i.e. paternal X inactivation, rather than the random X inactivation system of eutherian mammals. The bearing of the enzyme mobility data on phylogenetic relationships among macropodid species is discussed.

Comparative mitochondrial genome analysis of Pythium insidiosum and related oomycete species provides new insights into genetic variation and phylogenetic relationships

Gene ◽  
2016 ◽  
Vol 575 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Sithichoke Tangphatsornruang ◽  
Panthita Ruang-areerate ◽  
Duangjai Sangsrakru ◽  
Thidarat Rujirawat ◽  
Tassanee Lohnoo ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Mitochondrial Genome ◽  
Genome Analysis ◽  
Phylogenetic Relationships ◽  
Pythium Insidiosum

scholarly journals Sex-Linked and Maternal Effects in the Diallel Cross

1966 ◽  
Vol 19 (6) ◽  
pp. 1061 ◽  
Author(s):  
EJ Eisen ◽  
BB Bohren ◽  
HE Mckean
Keyword(s):  
Genetic Variation ◽  
Maternal Effects ◽  
Sex Chromosomes ◽  
Statistical Models ◽  
Diallel Cross ◽  
Inbred Lines ◽  
Diallel Crosses ◽  
Combining Abilities

The diallel cross has been used frequently in plant experiments to partition the genetic variation into general and specific combining abilities of inbred lines. The statistical models developed for analysis of diallel crosses in plants have been used in a number of studies of diallel crosses in mammals and poultry, without due consideration to the presence and effect of the sex chromosomes.

scholarly journals Evolution of dosage compensation does not depend on genomic background

2020 ◽  
Author(s):  
Michail Rovatsos ◽  
Lukáš Kratochvíl
Keyword(s):  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Genomic Region ◽  
Gene Copy ◽  
Gene Dose ◽  
Copy Numbers ◽  
Compensation Mechanisms ◽  
Gene Copy Numbers ◽  
Softshell Turtles

AbstractOrganisms evolved various mechanisms to cope with the differences in the gene copy numbers between sexes caused by degeneration of Y and W sex chromosomes. Complete dosage compensation or at least expression balance between sexes was reported predominantly in XX/XY, but rarely in ZZ/ZW systems. However, this often-reported pattern is based on comparisons of lineages where sex chromosomes evolved from non-homologous genomic regions, potentially differing in sensitivity to differences in gene copy numbers. Here we document that two reptilian lineages (XX/XY iguanas and ZZ/ZW softshell turtles), which independently co-opted the same ancestral genomic region for the function of sex chromosomes, evolved different gene dose regulatory mechanisms. The independent co-option of the same genomic region for the role of sex chromosome as in the iguanas and the softshell turtles offers a great opportunity for testing evolutionary scenarios on the sex chromosome evolution under the explicit control for the genomic background and for gene identity. We showed that the parallel loss of functional genes from the Y chromosome of the green anole and the W chromosome of the Florida softshell turtle led to different dosage compensation mechanisms. Our approach controlling for genetic background thus does not support that the variability in the regulation of the gene dose differences is a consequence of ancestral autosomal gene content.

scholarly journals Contingency in the convergent evolution of a regulatory network: Dosage compensation in Drosophila

2018 ◽  
Author(s):  
Doris Bachtrog ◽  
Chris Ellison
Keyword(s):  
Transposable Element ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Binding Sites ◽  
Evolutionary Biology ◽  
De Novo ◽  
Binding Motif ◽  
Sequence Motif ◽  
X Chromosomes ◽  
Msl Complex

The repeatability or predictability of evolution is a central question in evolutionary biology, and most often addressed in experimental evolution studies. Here, we infer how genetically heterogeneous natural systems acquire the same molecular changes, to address how genomic background affects adaptation in natural populations. In particular, we take advantage of independently formed neo-sex chromosomes in Drosophila species that have evolved dosage compensation by co-opting the dosage compensation (MSL) complex, to study the mutational paths that have led to the acquisition of 100s of novel binding sites for the MSL complex in different species. This complex recognizes a conserved 21-bp GA-rich sequence motif that is enriched on the X chromosome, and newly formed X chromosomes recruit the MSL complex by de novo acquisition of this binding motif. We identify recently formed sex chromosomes in the Drosophila repleta and robusta species groups by genome sequencing, and generate genomic occupancy maps of the MSL complex to infer the location of novel binding sites. We find that diverse mutational paths were utilized in each species to evolve 100s of de novo binding motifs along the neo-X, including expansions of microsatellites and transposable element insertions. However, the propensity to utilize a particular mutational path differs between independently formed X chromosomes, and appears to be contingent on genomic properties of that species, such as simple repeat or transposable element density. This establishes the “genomic environment” as an important determinant in predicting the outcome of evolutionary adaptations.

scholarly journals A Simple Method to Determine Critical Coagulation Concentration from Electrophoretic Mobility

2020 ◽  
Vol 4 (2) ◽  
pp. 20 ◽  
Author(s):  
Marco Galli ◽  
Szilárd Sáringer ◽  
István Szilágyi ◽  
Gregor Trefalt
Keyword(s):  
Electrophoretic Mobility ◽  
Dlvo Theory ◽  
Computational Method ◽  
Particle Aggregation ◽  
Critical Coagulation Concentration ◽  
Simple Method ◽  
Interparticle Forces ◽  
Mobility Data ◽  
Key Parameter ◽  
Multivalent Electrolytes

Critical coagulation concentration (CCC) is a key parameter of particle dispersions, since it provides the threshold limit of electrolyte concentrations, above which the dispersions are destabilized due to rapid particle aggregation. A computational method is proposed to predict CCC values using solely electrophoretic mobility data without the need to measure aggregation rates of the particles. The model relies on the DLVO theory; contributions from repulsive double-layer forces and attractive van der Waals forces are included. Comparison between the calculated and previously reported experimental CCC data for the same particles shows that the method performs well in the presence of mono and multivalent electrolytes provided DLVO interparticle forces are dominant. The method is validated for particles of various compositions, shapes, and sizes.

scholarly journals Extreme heterogeneity in sex chromosome differentiation and dosage compensation in livebearers

2019 ◽  
Vol 116 (38) ◽  
pp. 19031-19036 ◽  
Author(s):  
Iulia Darolti ◽  
Alison E. Wright ◽  
Benjamin A. Sandkam ◽  
Jake Morris ◽  
Natasha I. Bloch ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Poecilia Reticulata ◽  
Sex Chromosome ◽  
Sequencing Data ◽  
Chromosome Differentiation ◽  
Y Chromosomes ◽  
Shared Ancestry ◽  
Suppressed Recombination

Once recombination is halted between the X and Y chromosomes, sex chromosomes begin to differentiate and transition to heteromorphism. While there is a remarkable variation across clades in the degree of sex chromosome divergence, far less is known about the variation in sex chromosome differentiation within clades. Here, we combined whole-genome and transcriptome sequencing data to characterize the structure and conservation of sex chromosome systems across Poeciliidae, the livebearing clade that includes guppies. We found that the Poecilia reticulata XY system is much older than previously thought, being shared not only with its sister species, Poecilia wingei, but also with Poecilia picta, which diverged roughly 20 million years ago. Despite the shared ancestry, we uncovered an extreme heterogeneity across these species in the proportion of the sex chromosome with suppressed recombination, and the degree of Y chromosome decay. The sex chromosomes in P. reticulata and P. wingei are largely homomorphic, with recombination in the former persisting over a substantial fraction. However, the sex chromosomes in P. picta are completely nonrecombining and strikingly heteromorphic. Remarkably, the profound degradation of the ancestral Y chromosome in P. picta is counterbalanced by the evolution of functional chromosome-wide dosage compensation in this species, which has not been previously observed in teleost fish. Our results offer important insight into the initial stages of sex chromosome evolution and dosage compensation.

scholarly journals Finding a Balance: How Diverse Dosage Compensation Strategies Modify Histone H4 to Regulate Transcription

2012 ◽  
Vol 2012 ◽  
pp. 1-12
Author(s):  
Michael B. Wells ◽  
Györgyi Csankovszki ◽  
Laura M. Custer
Keyword(s):  
Gene Expression ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Current Understanding ◽  
Histone H4 ◽  
Linked Gene ◽  
Expression Levels ◽  
Gene Expression Levels

Dosage compensation balances gene expression levels between the sex chromosomes and autosomes and sex-chromosome-linked gene expression levels between the sexes. Different dosage compensation strategies evolved in different lineages, but all involve changes in chromatin. This paper discusses our current understanding of how modifications of the histone H4 tail, particularly changes in levels of H4 lysine 16 acetylation and H4 lysine 20 methylation, can be used in different contexts to either modulate gene expression levels twofold or to completely inhibit transcription.

Dosage compensation, the origin and the afterlife of sex chromosomes

2006 ◽  
Vol 14 (4) ◽  
pp. 417-431 ◽  
Author(s):  
Jan Larsson ◽  
Victoria H. Meller
Keyword(s):  
Dosage Compensation ◽  
Sex Chromosomes
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