Genetic Content of the Neo-Sex Chromosomes in Ctenonotus and Norops (Squamata, Dactyloidae) and Degeneration of the Y Chromosome as Revealed by High-Throughput Sequencing of Individual Chromosomes

2019 ◽  
Vol 157 (1-2) ◽  
pp. 115-122 ◽  
Author(s):  
Artem P. Lisachov ◽  
Alexey I. Makunin ◽  
Massimo Giovannotti ◽  
Jorge C. Pereira ◽  
Anna S. Druzhkova ◽  
...  
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
High Throughput ◽  
Sex Chromosomes ◽  
High Throughput Sequencing ◽  
Anolis Carolinensis ◽  
Pseudoautosomal Region ◽  
Central Component ◽  
Similar System ◽  
Divergence Estimates

Pleurodont lizards are characterized by an ancient system of sex chromosomes. Along with stability of the central component of the system (homologous to the X chromosome of Anolis carolinensis [Dactyloidae], ACAX), in some genera the ancestral sex chromosomes are fused with microautosomes, forming neo-sex chromosomes. The genus Ctenonotus (Dactyloidae) is characterized by multiple X1X1X2X2/X1X2Y sex chromosomes. According to cytogenetic data, the large neo-Y chromosome is formed by fusion of the ancestral Y chromosome with 2 microautosomes (homologous to ACA10 or ACA11 and ACA12), the X1 chromosome is formed by fusion of the ancestral X chromosome with the autosome homologous to ACA10 or ACA11, and the X2 chromosome is homologous to autosome ACA12. To determine more precisely the content and evolution of the Ctenonotus sex chromosomes, we sequenced flow-sorted chromosomes (both sex chromosomes and microautosomes as control) of 2 species with a similar system: C. pogus and C. sabanus. Our results indicate that the translocated part of the X1 is homologous to ACA11, X2 is homologous to ACA12, and the Y contains segments homologous to both ACA11 and ACA12. Molecular divergence estimates suggest that the ancestral X-derived part has completely degenerated in the Y of Ctenonotus, similar to the degeneration of the Norops sagrei Y chromosome (Dactyloidae). The newly added regions show loss of DNA content, but without degeneration of the conserved regions. We hypothesize that the translocation of autosomal blocks onto sex chromosomes facilitated rapid degeneration of the pseudoautosomal region on the ancestral Y.

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 Guppy Y Chromosome Integrity Maintained by Incomplete Recombination Suppression

2020 ◽  
Vol 12 (6) ◽  
pp. 965-977 ◽  
Author(s):  
Iulia Darolti ◽  
Alison E Wright ◽  
Judith E Mank
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Poecilia Reticulata ◽  
Sex Chromosome ◽  
Rna Seq ◽  
Recombination Suppression ◽  
Sex Chromosome System ◽  
Chromosome Integrity ◽  
Heterogametic Sex

Abstract The loss of recombination triggers divergence between the sex chromosomes and promotes degeneration of the sex-limited chromosome. Several livebearers within the genus Poecilia share a male-heterogametic sex chromosome system that is roughly 20 Myr old, with extreme variation in the degree of Y chromosome divergence. In Poecilia picta, the Y is highly degenerate and associated with complete X chromosome dosage compensation. In contrast, although recombination is restricted across almost the entire length of the sex chromosomes in Poecilia reticulata and Poecilia wingei, divergence between the X chromosome and the Y chromosome is very low. This clade therefore offers a unique opportunity to study the forces that accelerate or hinder sex chromosome divergence. We used RNA-seq data from multiple families of both P. reticulata and P. wingei, the species with low levels of sex chromosome divergence, to differentiate X and Y coding sequences based on sex-limited SNP inheritance. Phylogenetic tree analyses reveal that occasional recombination has persisted between the sex chromosomes for much of their length, as X- and Y-linked sequences cluster by species instead of by gametolog. This incomplete recombination suppression maintains the extensive homomorphy observed in these systems. In addition, we see differences between the previously identified strata in the phylogenetic clustering of X–Y orthologs, with those that cluster by chromosome located in the older stratum, the region previously associated with the sex-determining locus. However, recombination arrest appears to have expanded throughout the sex chromosomes more gradually instead of through a stepwise process associated with inversions.

Analysis of the sex chromosomes of the Mediterranean fruit fly by microdissected DNA probes

Genome ◽  
1998 ◽  
Vol 41 (1) ◽  
pp. 74-78 ◽  
Author(s):  
Ute Willhoeft ◽  
Jutta Mueller-Navia ◽  
Gerald Franz
Keyword(s):  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Fruit Fly ◽  
Mediterranean Fruit Fly ◽  
Oligonucleotide Primer ◽  
Mitotic Chromosomes ◽  
Degenerate Oligonucleotide ◽  
The Mediterranean

In the Mediterranean fruit fly, Ceratitis capitata, the sex-determining region maps to the long arm of the Y chromosome. DNA from this region of the Y chromosome and, for comparison, from the tip of the long arm of the X chromosome, was isolated by microdissection and amplified by degenerate oligonucleotide primer PCR (DOP-PCR). FISH of the Y-chromosomal microdissection products medY1-medY5 to mitotic chromosomes revealed hybridization signals on most of the long arm of the Y chromosome, including the male-determining region, and on the long arm of the X chromosome, as well as weaker signals on the autosomes, some of which were located in the heterochromatin next to the centromeres. The X-chromosomal microdissected probe medX1 revealed strong signals on the sex chromosomes and randomly distributed signals on the autosomes. Chromosomal in situ suppression hybridization indicates that the Y chromosome contains considerable amounts of Y-enriched and Y-specific sequences and that X-enriched sequences are present on the long arm of the X chromosome. The microdissected probes medY1, medY2, and medX1 hybridize to the sex chromosomes of two closely related species,Ceratitis rosa and Trirhithrum coffeae.

The Jumping SHOX Gene—Crossover in the Pseudoautosomal Region Resulting in Unusual Inheritance of Leri-Weill Dyschondrosteosis

2011 ◽  
Vol 96 (2) ◽  
pp. E356-E359 ◽  
Author(s):  
Sarina G. Kant ◽  
Hetty J. van der Kamp ◽  
Marjolein Kriek ◽  
Egbert Bakker ◽  
Boudewijn Bakker ◽  
...  
Keyword(s):  
Genetic Counseling ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosome ◽  
Recombination Frequency ◽  
Pseudoautosomal Region ◽  
Shox Gene ◽  
Mesomelic Dysplasia ◽  
Very High ◽  
Meiosis I

abstract Context: During meiosis I, the recombination frequency in the pseudoautosomal region on Xp and Yp (PAR1) in males is very high. As a result, mutated genes located within the PAR1 region can be transferred from the Y-chromosome to the X-chromosome and vice versa. Patients: Here we describe three families with SHOX abnormalities resulting in Leri-Weill dyschondrosteosis or Langer mesomelic dysplasia. Results: In about half of the segregations investigated, a transfer of the SHOX abnormality to the alternate sex chromosome was demonstrated. Conclusions: Patients with an abnormality of the SHOX gene should receive genetic counseling as to the likelihood that they may transmit the mutation or deletion to a son as well as to a daughter.

scholarly journals The Effect of Hybridization on Dosage Compensation in Member Species of the Anopheles gambiae Species Complex

2018 ◽  
Author(s):  
Kevin C. Deitz ◽  
Willem Takken ◽  
Michel A. Slotman
Keyword(s):  
Sex Determination ◽  
Anopheles Gambiae ◽  
Y Chromosome ◽  
X Chromosome ◽  
Dosage Compensation ◽  
Sex Chromosomes ◽  
Species Complex ◽  
F1 Hybrids ◽  
Chromosome Gene ◽  
Heterogametic Sex

AbstractDosage compensation has evolved in concert with Y-chromosome degeneration in many taxa that exhibit heterogametic sex chromosomes. Dosage compensation overcomes the biological challenge of a "half dose" of X chromosome gene transcripts in the heterogametic sex. The need to equalize gene expression of a hemizygous X with that of autosomes arises from the fact that the X chromosomes retain hundreds of functional genes that are actively transcribed in both sexes and interact with genes expressed on the autosomes. Sex determination and heterogametic sex chromosomes have evolved multiple times in Diptera, and in each case the genetic control of dosage compensation is tightly linked to sex determination. In the Anopheles gambiae species complex (Culicidae), maleness is conferred by the Y-chromosome gene Yob, which despite its conserved role between species is polymorphic in its copy number between them. Previous work demonstrated that male An. gambiae s.s. males exhibit complete dosage compensation in pupal and adult stages. In the present study we have extended this analysis to three sister species in the An. gambiae complex: An. coluzzii, An. arabiensis, and An. quadriannulatus. In addition, we analyzed dosage compensation in bi-directional F1 hybrids between these species to determine if hybridization results in the mis-regulation and disruption of dosage compensation. Our results confirm that dosage compensation operates in the An. gambiae species complex through the hyper-transcription of the male X chromosome. Additionally, dosage compensation in hybrid males does not differ from parental males, indicating that hybridization does not result in the mis-regulation of dosage compensation.

Chromosomes of Onchocerca volvulus (Spirurida:Onchocercidae): A comparative study between Nigeria and Guatemala

1987 ◽  
Vol 61 (1) ◽  
pp. 43-46 ◽  
Author(s):  
H. Hirai ◽  
I. Tada ◽  
H. Takahashi ◽  
B. E. B. Nwoke ◽  
G. O. Ufomadu
Keyword(s):  
Comparative Study ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Onchocerca Volvulus

ABSTRACTChromosomes of Nigerian Onchocerca volvulus were compared with those of Guatemalan O. volvulus. Both parasites had basically the same chromosomal construct (2n=8, XY type). Autosomes consisted of a pair of large and two smaller pairs. Sex chromosomes were made up of medium sized X chromosome and very small Y chromosome. It was not possible to infer the position of the centromeres.

LATE DNA REPLICATION PATTERN IN SEX CHROMOSOMES OF MELANDRIUM

1969 ◽  
Vol 11 (1) ◽  
pp. 192-198 ◽  
Author(s):  
Hiran C. Choudhuri
Keyword(s):  
Dna Replication ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Generation Time ◽  
Replication Pattern ◽  
Interphase Nuclei ◽  
Melandrium Album ◽  
S Period ◽  
Average Generation Time

DNA replication patterns in somatic cells of female and male Meladrium album were studied with autoradiographic methods. The S-period and the average generation time have been estimated to be 5.7 and 15.5 hours respectively. The heterochromatin observed in interphase nuclei may represent the late replicating and presumably inactivated sex chromosome.One arm of one X chromosome is late replicating in females. In the Y chromosome a region near the centromere replicates late in the S-period. The DNA replication sequence in sex chromosomes of female and male cells of Melandrium album suggests that their pattern is similar to that of mammalian sex chromosomes.

BANDING PATTERNS IN MITOTIC CHROMOSOMES OF THE RABBIT (ORYCTOLAGUS CUNICULUS)

1977 ◽  
Vol 19 (4) ◽  
pp. 625-632 ◽  
Author(s):  
F. P. H. Chan ◽  
F. R. Sergovich ◽  
E. L. Shaver
Keyword(s):  
Detailed Analysis ◽  
Y Chromosome ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Banding Pattern ◽  
Oryctolagus Cuniculus ◽  
Acrocentric Chromosome ◽  
Mitotic Chromosomes ◽  
Banding Patterns ◽  
Medium Length

A detailed analysis of rabbit mitotic chromosomes stained with quinacrine and Trypsin-Giemsa methods to elucidate the Q and G bands is presented. Each of the 21 pairs of autosomes can be identified unequivocally. The sex chromosomes can also be distinguished from the autosomes. The X chromosome is a medium length submetacentric with its own distinctive banding pattern. The Y chromosome is the smallest acrocentric chromosome and fluoresces with a medium intensity.

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