The Hypermethylated Regions in Avian Chromosomes

2017 ◽  
Vol 151 (4) ◽  
pp. 216-227 ◽  
Author(s):  
Michael Schmid ◽  
Claus Steinlein
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Bird Species ◽  
Evolutionary Process ◽  
General Rule ◽  
Centromeric Heterochromatin ◽  
Comparative Cytogenetics ◽  
Species Specific ◽  
Chromosome Segments ◽  
Chromosome Regions

Chromosomal locations and amounts of 5-methylcytosine-rich chromosome regions were detected in the karyotypes of 13 bird species by indirect immunofluorescence using a monoclonal anti-5-methylcytosine antibody. These species belong to 7 orders and 10 families of modern (Neognathae) and primitive (Palaeognathae) birds and are characterized by macro- and microchromosomes as well as ZW sex chromosomes. In all 13 species, the hypermethylated chromosome segments are confined to constitutive heterochromatin. The chromosomal locations of hypermethylated DNA regions in the karyotypes are constant and species-specific. There is no general rule with regard to the distribution of these hypermethylated chromosome regions in the genomes of birds. In most instances, hypermethylated segments are located in the centromeric regions of chromosomes, but in the sex chromosomes, these can also be found in telomeric and interstitial postitions. In most of the species studied, the centromeric heterochromatin in many, if not all, of the microchromosomes is hypermethylated. However, in one species, the only detectable hypermethylated heterochromatic regions are located in one pair of macroautosomes and in the Z sex chromosome, but none of the microchromosomes contains visible quantities of 5-methylcytosine. The analysis of 5-methylcytosine-rich chromosome regions can be very helpful for the comparative cytogenetics of closely related species or subspecies. It also reflects the dynamic evolutionary process operating in the highly repetitive DNA of eukaryotic chromosomes.

scholarly journals Hypermethylated Chromosome Regions in Nine Fish Species with Heteromorphic Sex Chromosomes

2015 ◽  
Vol 147 (2-3) ◽  
pp. 169-178 ◽  
Author(s):  
Michael Schmid ◽  
Claus Steinlein ◽  
Cassia F. Yano ◽  
Marcelo B. Cioffi
Keyword(s):  
Sex Chromosomes ◽  
Constitutive Heterochromatin ◽  
Banding Technique ◽  
Comparative Cytogenetics ◽  
Closely Related Species ◽  
Valuable Data ◽  
C Banding ◽  
Heteromorphic Sex Chromosomes ◽  
Species Specific ◽  
Chromosome Regions

Sites and amounts of 5-methylcytosine (5-MeC)-rich chromosome regions were detected in the karyotypes of 9 Brazilian species of Characiformes fishes by indirect immunofluorescence using a monoclonal anti-5-MeC antibody. These species, belonging to the genera Leporinus, Triportheus and Hoplias, are characterized by highly differentiated and heteromorphic ZW and XY sex chromosomes. In all species, the hypermethylated regions are confined to constitutive heterochromatin. The number and chromosome locations of hypermethylated heterochromatic regions in the karyotypes are constant and species-specific. Generally, heterochromatic regions that are darkly stained by the C-banding technique are distinctly hypermethylated, but several of the brightly fluorescing hypermethylated regions merely exhibit moderate or faint C-banding. The ZW and XY sex chromosomes of all 9 analyzed species also show species-specific heterochromatin hypermethylation patterns. The analysis of 5-MeC-rich chromosome regions contributes valuable data for comparative cytogenetics of closely related species and highlights the dynamic process of differentiation operating in the repetitive DNA fraction of sex chromosomes.

scholarly journals Meiotic Behavior of Achiasmate Sex Chromosomes in the African Pygmy Mouse Mus mattheyi Offers New Insights into the Evolution of Sex Chromosome Pairing and Segregation in Mammals

Genes ◽  
2021 ◽  
Vol 12 (9) ◽  
pp. 1434
Author(s):  
Ana Gil-Fernández ◽  
Marta Ribagorda ◽  
Marta Martín-Ruiz ◽  
Pablo López-Jiménez ◽  
Tamara Laguna ◽  
...  
Keyword(s):  
Dna Repair ◽  
Y Chromosome ◽  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Mammalian Species ◽  
Evolutionary Process ◽  
Small Region ◽  
Pseudoautosomal Region ◽  
Evolution Of Sex ◽  
African Pygmy Mouse

X and Y chromosomes in mammals are different in size and gene content due to an evolutionary process of differentiation and degeneration of the Y chromosome. Nevertheless, these chromosomes usually share a small region of homology, the pseudoautosomal region (PAR), which allows them to perform a partial synapsis and undergo reciprocal recombination during meiosis, which ensures their segregation. However, in some mammalian species the PAR has been lost, which challenges the pairing and segregation of sex chromosomes in meiosis. The African pygmy mouse Mus mattheyi shows completely differentiated sex chromosomes, representing an uncommon evolutionary situation among mouse species. We have performed a detailed analysis of the location of proteins involved in synaptonemal complex assembly (SYCP3), recombination (RPA, RAD51 and MLH1) and sex chromosome inactivation (γH2AX) in this species. We found that neither synapsis nor chiasmata are found between sex chromosomes and their pairing is notably delayed compared to autosomes. Interestingly, the Y chromosome only incorporates RPA and RAD51 in a reduced fraction of spermatocytes, indicating a particular DNA repair dynamic on this chromosome. The analysis of segregation revealed that sex chromosomes are associated until metaphase-I just by a chromatin contact. Unexpectedly, both sex chromosomes remain labelled with γH2AX during first meiotic division. This chromatin contact is probably enough to maintain sex chromosome association up to anaphase-I and, therefore, could be relevant to ensure their reductional segregation. The results presented suggest that the regulation of both DNA repair and epigenetic modifications in the sex chromosomes can have a great impact on the divergence of sex chromosomes and their proper transmission, widening our understanding on the relationship between meiosis and the evolution of sex chromosomes in mammals.

scholarly journals The Effects of the Sex Chromosomes on the Inheritance of Species Specific Traits of the Shape of the Copulatory Organ in Drosophila virilis and Drosophila lummei

2020 ◽  
Author(s):  
Alex M Kulikov ◽  
Svetlana Yu Sorokina ◽  
Anton I Melnikov ◽  
Nick G Gornostaev ◽  
Dmitriy G Seleznev ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Copulatory Organ ◽  
Male Parent ◽  
Drosophila Virilis ◽  
Interspecific Crosses ◽  
Male Mating ◽  
Epistatic Interactions ◽  
Epigenetic Effects ◽  
Species Specific

Abstract Background. It is well known that the shape of the male copulatory system is strongly associated with mating behavior in Drosophila. The shape of the male genitalia is also known as the most rapidly evolving structure among all morphological characters. However, only a part of the male copulating system, namely epandrium, has actually been used as the only model to study the genetic basis of species-specific differences in the shape of the copulatory system in D. simulans and D. mauritiana. Almost nothing is known about the effects of both sex chromosomes on the shape of the male mating organ. Results. Seven factors were isolated that describe variation of different parts of the male mating organ. The shape of the male mating organ depends on the combination of the sex chromosome status, the autosome status, and the male parent identity as an epigenetic factor. The effect of the male parent identity is possibly mediated through the epigenetic marking of chromosomes in interspecific hybrids during gametogenesis and a subsequent effect of the resulting signatures on the ontogeny of offspring. Epistatic interactions of the sex chromosomes and autosomes and epigenetic effects of the male parent origin from interspecific crosses influence the expression of species-specific traits in the shape of the male copulatory system. Conclusions. Epistatic interactions of the sex chromosomes and autosomes and epigenetic effects of the male parent origin from interspecific crosses influence the expression of species-specific traits in the shape of the male copulatory system. It can be assumed that sexual selection for specific genes associated with male traits implemented in the courtship ritual prevents the well-known effect of demasculinization of the X chromosome.

scholarly journals Evolutionary Variability of W-Linked Repetitive Content in Lacertid Lizards

Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 531
Author(s):  
Grzegorz Suwala ◽  
Marie Altmanová ◽  
Sofia Mazzoleni ◽  
Emmanouela Karameta ◽  
Panayiotis Pafilis ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Phylogenetic Signal ◽  
Z Chromosome ◽  
Specific Gene ◽  
W Chromosome ◽  
Squamate Reptiles ◽  
Lacertid Lizards ◽  
Species Specific

Lacertid lizards are a widely radiated group of squamate reptiles with long-term stable ZZ/ZW sex chromosomes. Despite their family-wide homology of Z-specific gene content, previous cytogenetic studies revealed significant variability in the size, morphology, and heterochromatin distribution of their W chromosome. However, there is little evidence about the accumulation and distribution of repetitive content on lacertid chromosomes, especially on their W chromosome. In order to expand our knowledge of the evolution of sex chromosome repetitive content, we examined the topology of telomeric and microsatellite motifs that tend to often accumulate on the sex chromosomes of reptiles in the karyotypes of 15 species of lacertids by fluorescence in situ hybridization (FISH). The topology of the above-mentioned motifs was compared to the pattern of heterochromatin distribution, as revealed by C-banding. Our results show that the topologies of the examined motifs on the W chromosome do not seem to follow a strong phylogenetic signal, indicating independent and species-specific accumulations. In addition, the degeneration of the W chromosome can also affect the Z chromosome and potentially also other parts of the genome. Our study provides solid evidence that the repetitive content of the degenerated sex chromosomes is one of the most evolutionary dynamic parts of the genome.

scholarly journals Chromosomal Mapping of Repetitive DNAs in Myiopsitta monachus and Amazona aestiva (Psittaciformes, Psittacidae) with Emphasis on the Sex Chromosomes

2017 ◽  
Vol 151 (3) ◽  
pp. 151-160 ◽  
Author(s):  
Ivanete de Oliveira Furo ◽  
Rafael Kretschmer ◽  
Michelly S. dos Santos ◽  
Carlos A. de Lima Carvalho ◽  
Ricardo J. Gunski ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Evolutionary Process ◽  
Distal Region ◽  
Chromosomal Mapping ◽  
W Chromosome ◽  
Repetitive Dnas ◽  
Myiopsitta Monachus ◽  
First Time ◽  
Whole Chromosome Painting

Here, for the first time, we describe the karyotype of Myiopsitta monachus (Psittacidae, Arini). We found 2n = 48, corresponding to the lowest diploid number observed in Neotropical Psittaciformes so far, with an uncommonly large W chromosome homomorphic to the Z. In order to better understand the evolution of the sex chromosomes in this species, we applied several molecular cytogenetic approaches, including C-banding, FISH mapping of repetitive DNAs (several microsatellite repeats), and whole-chromosome painting on metaphases of M. monachus. For comparison, another species belonging to the same tribe but with a smaller W chromosome (A. aestiva) was also analyzed. The results show that the constitutive heterochromatin has a very diverse distribution pattern in these species revealing heterochromatic blocks in the centromeric region of all chromosomes and in most of the length of the W chromosome in A. aestiva, while in M. monachus they were found in interstitial and telomeric regions. Concerning the microsatellites, only the sequence (CG)n produced signals on the W chromosome of A. aestiva, in the distal region of both arms. However, in M. monachus, (CAA)n, (CAG)n, and (CG)n probes were accumulated on the W chromosome, and, in addition, the sequence (CAG)n also hybridized to heterochromatic regions in macrochromosomes, as well as in microchromosomes. Based on these results, we suggest that the increase in length of the W chromosome in M. monachus is due to the amplification of repetitive elements, which highlights their significant role in the evolutionary process of sex chromosome differentiation.

5-Methylcytosine-Rich Heterochromatin in Reptiles

2019 ◽  
Vol 157 (1-2) ◽  
pp. 53-64 ◽  
Author(s):  
Michael Schmid ◽  
Claus Steinlein ◽  
Alina M. Reiter ◽  
Michail Rovatsos ◽  
Marie Altmanová ◽  
...  
Keyword(s):  
Indirect Immunofluorescence ◽  
Sex Chromosomes ◽  
Dna Sequences ◽  
Experimental Approach ◽  
Constitutive Heterochromatin ◽  
Banding Patterns ◽  
Turtle Species ◽  
C Banding ◽  
Species Specific ◽  
Chromosome Regions

An experimental approach using monoclonal anti-5-methylcytosine antibodies and indirect immunofluorescence was elaborated for detecting 5-methylcytosine-rich chromosome regions in reptilian chromosomes. This technique was applied to conventionally prepared mitotic metaphases of 2 turtle species and 12 squamate species from 8 families. The hypermethylation patterns were compared with C-banding patterns obtained by conventional banding techniques. The hypermethylated DNA sequences are species-specific and are located in constitutive heterochromatin. They are highly reproducible and often found in centromeric, pericentromeric, and interstitial positions of the chromosomes. Heterochromatic regions in differentiated sex chromosomes are particularly hypermethylated.

scholarly journals The Role of the Sex Chromosomes in the Inheritance of Species Specific Traits of the Shape of the Copulatory Organ in Drosophila

2017 ◽  
Author(s):  
Alex M. Kulikov ◽  
Svetlana Yu. Sorokina ◽  
Anton I. Melnikov ◽  
Nick G. Gornostaev ◽  
Dmitriy G. Seleznev ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Parental Species ◽  
Copulatory Organ ◽  
Interspecific Crosses ◽  
Epigenetic Factors ◽  
Factors Associated ◽  
Species Specific ◽  
Paternal Genotype

The sex chromosomes of the parental species, D. virilis and D. lummei were tested for the effect on trait dominance in the shape of the copulatory system in the interspecific crosses. The origin of the sex chromosome and the paternal genotype were found to affect the trait dominance in D. lummei × D. virilis progeny and backcross males heterozygous for the autosomes. A correlated variability analysis showed that the two sex chromosomes exert unidirectional effects, shifting dominance towards the conspecific phenotype. The effect of the X chromosome is to a great extent determined by epigenetic factors associated with the paternal genotype.

scholarly journals Genomic Differences Between the Sexes in a Fish Species Seen Through Satellite DNAs

2021 ◽  
Vol 12 ◽  
Author(s):  
Carolina Crepaldi ◽  
Emiliano Martí ◽  
Évelin Mariani Gonçalves ◽  
Dardo Andrea Martí ◽  
Patricia Pasquali Parise-Maltempi
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Satellite Dnas ◽  
Closely Related Species ◽  
Neotropical Fishes ◽  
Heteromorphic Sex Chromosomes ◽  
Sex Chromosome System ◽  
Species Specific ◽  
Female Genome ◽  
Shed Light

Neotropical fishes have highly diversified karyotypic and genomic characteristics and present many diverse sex chromosome systems, with various degrees of sex chromosome differentiation. Knowledge on their sex-specific composition and evolution, however, is still limited. Satellite DNAs (satDNAs) are tandemly repeated sequences with pervasive genomic distribution and distinctive evolutionary pathways, and investigating satDNA content might shed light into how genome architecture is organized in fishes and in their sex chromosomes. The present study investigated the satellitome of Megaleporinus elongatus, a freshwater fish with a proposed Z1Z1Z2Z2/Z1W1Z2W2 multiple sex chromosome system that encompasses a highly heterochromatic and differentiated W1 chromosome. The species satellitome comprises of 140 different satDNA families, including previously isolated sequences and new families found in this study. This diversity is remarkable considering the relatively low proportion that satDNAs generally account for the M. elongatus genome (around only 5%). Differences between the sexes in regards of satDNA content were also evidenced, as these sequences are 14% more abundant in the female genome. The occurrence of sex-biased signatures of satDNA evolution in the species is tightly linked to satellite enrichment associated with W1 in females. Although both sexes share practically all satDNAs, the overall massive amplification of only a few of them accompanied the W1 differentiation. We also investigated the expansion and diversification of the two most abundant satDNAs of M. elongatus, MelSat01-36 and MelSat02-26, both highly amplified sequences in W1 and, in MelSat02-26’s case, also harbored by Z2 and W2 chromosomes. We compared their occurrences in M. elongatus and the sister species M. macrocephalus (with a standard ZW sex chromosome system) and concluded that both satDNAs have led to the formation of highly amplified arrays in both species; however, they formed species-specific organization on female-restricted sex chromosomes. Our results show how satDNA composition is highly diversified in M. elongatus, in which their accumulation is significantly contributing to W1 differentiation and not satDNA diversity per se. Also, the evolutionary behavior of these repeats may be associated with genome plasticity and satDNA variability between the sexes and between closely related species, influencing how seemingly homeologous heteromorphic sex chromosomes undergo independent satDNA evolution.

scholarly journals The long and the short of avian W chromosomes: no evidence for gradual W shortening

2012 ◽  
Vol 8 (4) ◽  
pp. 636-638 ◽  
Author(s):  
Joanna Rutkowska ◽  
Malgorzata Lagisz ◽  
Shinichi Nakagawa
Keyword(s):  
Sex Chromosomes ◽  
Large Scale ◽  
Sex Chromosome ◽  
Bird Species ◽  
Chromosome Morphology ◽  
W Chromosome ◽  
Evolutionary Time ◽  
Coding Regions ◽  
Its Gene ◽  
Short Time

The well-established view of the evolution of sex chromosome dimorphism is of a gradual genetic and morphological degeneration of the hemizygous chromosome. Yet, no large-scale comparative analysis exists to support this view. Here, we analysed karyotypes of 200 bird species to test whether the supposed directional changes occur in bird sex chromosomes. We found no support for the view that W chromosomes gradually become smaller over evolutionary time. On the contrary, the length of the W chromosome can fluctuate over short time scales, probably involving both shortening and elongation of non-coding regions. Recent discoveries of near-identical palindromes and neo-sex chromosomes in birds may also contribute to the observed variation. Further studies are now needed to investigate how chromosome morphology relates to its gene content, and whether the changes in size were driven by selection.

scholarly journals Extreme variation in recombination rate and genetic variation along the Sylvioidea neo-sex chromosome

2020 ◽  
Author(s):  
Suvi Ponnikas ◽  
Hanna Sigeman ◽  
Max Lundberg ◽  
Bengt Hansson
Keyword(s):  
Sex Chromosomes ◽  
Recombination Rate ◽  
Sex Chromosome ◽  
Bird Species ◽  
Pseudoautosomal Region ◽  
Z Chromosome ◽  
Strong Impact ◽  
Sequence Evolution ◽  
Apparent Lack ◽  
Extreme Variation

In the majority of bird species, recombination between the sex chromosome pairs in heterogametic females (ZW) is restricted to a small pseudoautosomal region (PAR), whereas recombination is ongoing along the entire Z chromosome in the homogametic males (ZZ). Recombination has a strong impact on the sequence evolution by affecting the extent of linkage, level of genetic diversity and efficacy of selection. Species within the Sylvioidea superfamily are unique among birds in having extended Z and W chromosomes (neo-sex chromosomes) formed by a fusion between the ancestral sex chromosomes and a part of chromosome 4A. So far the recombination landscape of the Sylvioidea neo-sex chromosomes remains unknown, despite its importance for understanding sequence evolution. Here, we use linkage mapping in a multi-generation pedigree to assemble, and assess the recombination rate along the entire Z chromosome of one Sylvioidea species, the great reed warbler (Acrocephalus arundinaceus). This resulted in an 87.54 Mbp and 90.19 cM large Z including the ancestral-Z, where the small PAR (0.89 Mbp) is located, and the added-Z. A striking result was an extreme variation in recombination rate along the Z in male great reed warblers with high rates at both telomeric ends, but an apparent lack of recombination over a substantial central section, covering 77% of the chromosome. This region showed a drastic loss of nucleotide diversity and accumulation of repeats compared to the highly recombining regions. Nonetheless, the evolutionary rate of genes (measured by dN/dS) did not differ between these regions, suggesting that the efficacy of selection on protein-coding sequences is not reduced by lack of recombination.

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