Heterochromatin characterization of sex chromosomes in Triturus marmoratus (Urodela, Salamandridae)

1992 ◽  
Vol 60 (2) ◽  
pp. 150-153 ◽  
Author(s):  
P. Herrero ◽  
J de la Torre ◽  
J. Gosálvez ◽  
A.T. Sumner
Keyword(s):  
Sex Chromosomes ◽  
Triturus Marmoratus

Characterization of sex chromosomes in three deeply diverged species of Pseudocrenilabrinae (Teleostei: Cichlidae)

Hydrobiologia ◽  
2018 ◽  
Vol 832 (1) ◽  
pp. 397-408 ◽  
Author(s):  
William J. Gammerdinger ◽  
Matthew A. Conte ◽  
Benjamin A. Sandkam ◽  
David J. Penman ◽  
Thomas D. Kocher
Keyword(s):  
Sex Chromosomes

scholarly journals Development and characterization of DNA sequence OmyP9 associated with the sex chromosomes in rainbow trout

Heredity ◽  
2001 ◽  
Vol 86 (4) ◽  
pp. 412-419 ◽  
Author(s):  
Patricia Iturra ◽  
Mark Bagley ◽  
Nora Vergara ◽  
Paula Imbert ◽  
Juan F Medrano
Keyword(s):  
Rainbow Trout ◽  
Dna Sequence ◽  
Sex Chromosomes

Chromosomal synapsis and the meiotic process in male mesquite lizards, Sceloporus grammicus complex

Genome ◽  
1992 ◽  
Vol 35 (3) ◽  
pp. 398-408 ◽  
Author(s):  
Kent M. Reed ◽  
Jack W. Sites Jr. ◽  
Ira F. Greenbaum
Keyword(s):  
Synaptonemal Complex ◽  
Sex Chromosomes ◽  
Meiotic Prophase ◽  
Morphological Characterization ◽  
Autosomal Bivalents ◽  
Meiotic Process ◽  
Low Levels ◽  
Sceloporus Grammicus ◽  
Metaphase I

Meiosis in males of the F5 cytotype of Sceloporus grammicus was examined through the analysis of synaptonemal complexes (SCs), diakinetic (metaphase I) nuclei, and secondary spermatocytes (metaphase II configurations). These data allowed the establishment of criteria for substaging of zygonema and pachynema, morphological characterization of the SC complement, and comparison of the orientation and segregation of the autosomes and sex chromosomes. The analysis of nuclei from all stages of meiotic prophase I (leptonema through diakinesis) provided a useful means of partitioning the temporal sequence of early meiotic events. Three substages of zygonema (Z1–Z3) were established, based on the extent of synapsis of the microchromosomal and macrochromosomal elements. Synaptic initiation of the autosomes and sex chromosomes was synchronous. Two patterns of macrochromosomal synapsis were observed. Whereas synapsis of the biarmed elements was biterminal (i.e., progressing from both ends of the homologs), synapsis of the acrocentric elements was uniterminal involving only the distal (noncentromeric) ends of the homologs. Unique sex-chromosomal characteristics were not observed in S. grammicus and, therefore, the substaging of pachynema was based on subjective criteria. Examination of diakinesis – metaphase I and metaphase II configurations indicated low levels of diakinetic irregularities with balanced segregation of the autosomal bivalents and the sex-chromosomal trivalent.Key words: Sceloporus grammicus, meiosis, synaptonemal complex, substaging.

Characterization of the lampbrush chromosomes of the marbled newt Triturus marmoratus (Latreille, 1800)

Chromosoma ◽  
1972 ◽  
Vol 37 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Irma Nardi ◽  
Matilde Ragghianti ◽  
Giorgio Mancino
Keyword(s):  
Lampbrush Chromosomes ◽  
Triturus Marmoratus

In situ enzymatic denaturation and random oligonucleotide priming of DNA selectively stains centromeric heterochromatin in Triturus marmoratus (Salamandridae: Caudata)

Genome ◽  
1991 ◽  
Vol 34 (5) ◽  
pp. 769-771 ◽  
Author(s):  
P. Herrero ◽  
J. L. Bella ◽  
J. de la Torre ◽  
J. Gosálvez
Keyword(s):  
Restriction Endonuclease ◽  
Centromeric Heterochromatin ◽  
Enzymatic Production ◽  
Exonuclease Iii ◽  
Selective Labelling ◽  
Random Priming ◽  
Klenow Polymerase ◽  
Triturus Marmoratus

Enzymatic production of single-stranded DNA with the HaeIII restriction endonuclease and exonuclease III has been used for chromosome labelling involving random primer extension and incorporation of biotinylated nucleotides with the Klenow polymerase on fixed chromosomes of Triturus marmoratus. Results show repetitive and selective labelling of centromeric heterochromatin, while remaining heterochromatin does not exhibit a positive response. This method of chromosome labelling permits the characterization of specific fractions of the heterochromatin and can be used for the analysis of heterochromatin heterogeneity within a given genome.Key words: Triturus marmoratus, cytogenetics, heterochromatin, restriction endonuclease DNA denaturation, random priming.

scholarly journals FindZX: an automated pipeline for detecting and visualising sex chromosomes using whole-genome sequencing data

2021 ◽  
Author(s):  
Hanna Sigeman ◽  
Bella Sinclair ◽  
Bengt Hansson
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Whole Genome Sequencing Data ◽  
Sequencing Data ◽  
A Genome ◽  
Genomic Studies ◽  
Taxonomic Groups ◽  
User Friendly ◽  
Genomic Patterns

Sex chromosomes have evolved numerous times, as revealed by recent genomic studies. However, large gaps in our knowledge of sex chromosome diversity across the tree of life remain. Filling these gaps, through the study of novel species, is crucial for improved understanding of why and how sex chromosomes evolve. Characterization of sex chromosomes in already well-studied organisms is also important to avoid misinterpretations of population genomic patterns caused by undetected sex chromosome variation. Here we present findZX, an automated Snakemake-based computational pipeline for detecting and visualizing sex chromosomes through differences in genome coverage and heterozygosity between males and females. FindZX is user-friendly and scalable to suit different computational platforms and works with any number of male and female samples. An option to perform a genome coordinate lift-over to a reference genome of another species allows users to inspect sex- linked regions over larger contiguous chromosome regions, while also providing important between- species synteny information. To demonstrate its effectiveness, we applied findZX to publicly available genomic data from species belonging to widely different taxonomic groups (mammals, birds, reptiles, fish, and insects), with sex chromosome systems of different ages, sizes, and levels of differentiation. We also demonstrate that the lift-over method is robust over large phylogenetic distances (>80 million years of evolution).

scholarly journals MEIOSIS IN MALE DROSOPHILA MELANOGASTER I. ISOLATION AND CHARACTERIZATION OF MEIOTIC MUTANTS AFFECTING SECOND CHROMOSOME DISJUNCTION

Genetics ◽  
1974 ◽  
Vol 78 (4) ◽  
pp. 1127-1142
Author(s):  
Richard C Gethmann
Keyword(s):  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Chromosome Loss ◽  
Meiotic Mutants ◽  
Isolation And Characterization ◽  
Males And Females ◽  
Chromosome Nondisjunction ◽  
Chromosome Disjunction

ABSTRACT Two second chromosome, EMS-induced, meiotic mutants which cause an increase in second chromosome nondisjunction are described. The first mutant is recessive and causes an increase in second chromosome nondisjunction in both males and females. It causes no increase in nondisjunction of the sex chromosomes in either sex, nor of the third chromosome in females. No haplo-4-progeny were recovered from either sex. Thus, it appears that this mutant, which is localized to the second chromosome, affects only second chromosome disjunction and acts in both sexes.—The other mutant affects chromosome disjunction in males and has no effect in females. Nondisjunction occurs at the first meiotic division. Sex chromosome disjunction in the presence of this mutant is similar to that of sc4sc8, with an excess of X and nullo-XY sperm relative to Y and XY sperm. In some lines, there is an excess of nullo-2 sperm relative to diplo-2 sperm, which appears to be regulated, in part, by the Y chromosome. A normal Y chromosome causes an increase in nullo-2 sperm, where BsY does not. There is also a high correlation between second and sex chromosome nondisjunction. Nearly half of the second chromosome exceptions are also nondisjunctional for the sex chromosomes. Among the double exceptions, there is an excess of XY nullo-2 and nullo-XY diplo-2 gametes. Meiotic drive, chromosome loss and nonhomologous pairing are considered as possible explanations for the double exceptions.

scholarly journals Characterization of a sex-determining region and its genomic context via statistical estimates of haplotype frequencies in daughters and sons sequenced in pools

2020 ◽  
Author(s):  
Richard Cordaux ◽  
Mohamed Amine Chebbi ◽  
Isabelle Giraud ◽  
David Pleydell ◽  
Jean Peccoud
Keyword(s):  
Sex Chromosomes ◽  
Strong Evidence ◽  
Bayesian Method ◽  
Genomic Region ◽  
Genomic Context ◽  
Statistical Estimates ◽  
Haplotype Frequencies ◽  
Show Evidence ◽  
Female Specific

AbstractSex chromosomes are generally derived from a pair of autosomes that have acquired a locus controlling sex. Sex chromosomes usually evolve reduced recombination around this locus and undergo a long process of molecular divergence. Although sex chromosomes have been intensively studied in several model taxa, the actual loci controlling sex are difficult to identify in highly diverged sex chromosomes, hence they are known in relatively few species. Taxa with evolutionarily young sex chromosomes can help fill this gap in knowledge. Here we aimed at pinpointing the sex-determining region (SDR) of Armadillidium vulgare, a terrestrial isopod with female heterogamety (ZW females and ZZ males) and which presumably presents evolutionarily young sex chromosomes. To locate the SDR, we assessed SNP allele frequencies in F1 daughters and sons sequenced in pools (pool-seq) in several families. We developed a Bayesian method that uses the SNP genotypes of individually sequenced parents and poolseq data from F1 siblings to estimate the genetic distance between a given genomic region (contig) and the SDR. This allowed us to assign more than 43 Megabases of contigs to sex chromosomes. By taking advantage of the several F1 families, we delineated a very short genomic region (~65 kilobases) that did not show evidence for recombination with the SDR. In this region, the comparison of sequencing depths between sexes outlined female-specific genes that may be involved in sex determination. Overall, our results provide strong evidence for an extremely low divergence of sex chromosomes in A. vulgare.

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