On sex determination in the Turkish desert woodlouse Hemilepistus elongatus (Crustacea, Isopoda, Oniscidea): searching for sex chromosomes and for sex-specific differences in simple DNA repeats

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 818-821 ◽  
Author(s):  
G. Röder ◽  
K. E. Linsenmair ◽  
I. Nanda ◽  
M. Schmid
Keyword(s):  
Chromosome Number ◽  
Sex Determination ◽  
Sex Chromosomes ◽  
Genomic Dna ◽  
Constitutive Heterochromatin ◽  
Dna Repeats ◽  
Male And Female ◽  
General Morphology ◽  
C Banding ◽  
Heteromorphic Sex Chromosomes

The karyotype of male and female Hemilepistus elongatus was investigated by means of C-banding. The diploid chromosome number in both sexes is 2n = 50. By scrutinizing general morphology and localization of the constitutive heterochromatin, no heteromorphic sex chromosomes were found. All chromosome pairs in males are well paired during diakinesis. Hybridization of genomic DNA with (GACA)4 and (GATA)4 oligonucleotides revealed no sex-specific patterns. Key words : karyotype, C-banding, sex determination, simple DNA-repeats, Isopoda.

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 The Diversity and Evolution of Sex Chromosomes in Frogs

Genes ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 483
Author(s):  
Wen-Juan Ma ◽  
Paris Veltsos
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Chromosome Evolution ◽  
Sex Chromosome ◽  
Comparative Genomic ◽  
Ancestral State ◽  
Heteromorphic Sex Chromosomes ◽  
Genomic Studies ◽  
Evolutionary Trajectories ◽  
Heterogametic Sex

Frogs are ideal organisms for studying sex chromosome evolution because of their diversity in sex chromosome differentiation and sex-determination systems. We review 222 anuran frogs, spanning ~220 Myr of divergence, with characterized sex chromosomes, and discuss their evolution, phylogenetic distribution and transitions between homomorphic and heteromorphic states, as well as between sex-determination systems. Most (~75%) anurans have homomorphic sex chromosomes, with XY systems being three times more common than ZW systems. Most remaining anurans (~25%) have heteromorphic sex chromosomes, with XY and ZW systems almost equally represented. There are Y-autosome fusions in 11 species, and no W-/Z-/X-autosome fusions are known. The phylogeny represents at least 19 transitions between sex-determination systems and at least 16 cases of independent evolution of heteromorphic sex chromosomes from homomorphy, the likely ancestral state. Five lineages mostly have heteromorphic sex chromosomes, which might have evolved due to demographic and sexual selection attributes of those lineages. Males do not recombine over most of their genome, regardless of which is the heterogametic sex. Nevertheless, telomere-restricted recombination between ZW chromosomes has evolved at least once. More comparative genomic studies are needed to understand the evolutionary trajectories of sex chromosomes among frog lineages, especially in the ZW systems.

CHROMOSOMES AND DNA OF MICROTUS II. CONFIRMATION OF DELETION OF CONSTITUTIVE HETEROCHROMATIN IN M. AGRESTIS CELLS IN VITRO

1977 ◽  
Vol 19 (3) ◽  
pp. 537-541 ◽  
Author(s):  
J. E. K. Cooper
Keyword(s):  
Somatic Cell ◽  
Cell Line ◽  
Cell Lines ◽  
X Chromosome ◽  
Sex Chromosomes ◽  
Constitutive Heterochromatin ◽  
The Other ◽  
Microtus Agrestis ◽  
C Banding

The distribution of constitutive heterochromatin has been examined by C-banding in two somatic cell lines, grown in vitro, from a female Microtus agrestis. One line retains one intact X chromosome together with the short arm of the other X chromosome, while the other cell line retains only the short arm of one X chromosome. Thus, each cell line has lost substantial amounts of heterochromatin from the sex chromosomes, but this material has been deleted from the cells, and not translocated to other chromosomes. Nonetheless, both cell lines continue to propagate well in vitro.

scholarly journals Do male and female heterogamety really differ in expression regulation? Lack of global dosage balance in pygopodid geckos

2021 ◽  
Vol 376 (1833) ◽  
pp. 20200102 ◽  
Author(s):  
Michail Rovatsos ◽  
Tony Gamble ◽  
Stuart V. Nielsen ◽  
Arthur Georges ◽  
Tariq Ezaz ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosomes ◽  
Gene Dosage ◽  
Regulatory Mechanisms ◽  
Gene Copy ◽  
Male And Female ◽  
Gene Dose ◽  
Female Heterogamety ◽  
Dosage Balance ◽  
Male Heterogamety

Differentiation of sex chromosomes is thought to have evolved with cessation of recombination and subsequent loss of genes from the degenerated partner (Y and W) of sex chromosomes, which in turn leads to imbalance of gene dosage between sexes. Based on work with traditional model species, theory suggests that unequal gene copy numbers lead to the evolution of mechanisms to counter this imbalance. Dosage compensation, or at least achieving dosage balance in expression of sex-linked genes between sexes, has largely been documented in lineages with male heterogamety (XX/XY sex determination), while ZZ/ZW systems are assumed to be usually associated with the lack of chromosome-wide gene dose regulatory mechanisms. Here, we document that although the pygopodid geckos evolved male heterogamety with a degenerated Y chromosome 32–72 Ma, one species in particular, Burton's legless lizard ( Lialis burtonis ), does not possess dosage balance in the expression of genes in its X-specific region. We summarize studies on gene dose regulatory mechanisms in animals and conclude that there is in them no significant dichotomy between male and female heterogamety. We speculate that gene dose regulatory mechanisms are likely to be related to the general mechanisms of sex determination instead of type of heterogamety. This article is part of the theme issue ‘Challenging the paradigm in sex chromosome evolution: empirical and theoretical insights with a focus on vertebrates (Part II)’.

scholarly journals RAPD-based analysis of differences between male and female genotypes of Asparagus officinalis

2012 ◽  
Vol 39 (No. 1) ◽  
pp. 33-37 ◽  
Author(s):  
Y. Ii ◽  
A. Uragami ◽  
Y. Uno ◽  
M. Kanechi ◽  
N. Inagaki
Keyword(s):  
Molecular Markers ◽  
Sex Determination ◽  
Genomic Dna ◽  
Asparagus Officinalis ◽  
Breeding Line ◽  
Male And Female ◽  
Future Studies ◽  
Random Primers

Asparagus (Asparagus officinalis L.) plants are dioecious. All-male cultivars are desired because of their higher yields. To increase the proportion of male individuals planted in the field and expedite the breeding of all-male cultivars in asparagus, development of generally applicable molecular markers to distinguish male and female individuals is required. Bulked genomic DNA samples from ten male (XY) and ten female (XX) plants was screened with 10-bp random primers. Of the 188 primers tested, the primer T35R54 produced a 1600-bp fragment observed only in male individuals. The specificity of this T35R54-1600 marker was verified using DNA from one supermale (YY) and one female (XX) breeding line and their four F<sub>1</sub> progenies (XY). The T35R54-1600 marker fragment was observed in both supermale and all-male lines. The sequence of the T35R54 primer (5'-TTCACGGTGG-3') was absent among the sequences of primers or amplified fragments from previous studies. Therefore, this marker could be useful as a sex-related marker in future studies to increase the reliability of sex determination in asparagus.

scholarly journals Karyotype and genome size determination of Jarilla chocola, an additional sister clade of Carica papaya

Plant Omics ◽  
2021 ◽  
pp. 50-56
Author(s):  
Dessireé Patricia Zerpa-Catanho ◽  
Tahira Jatt ◽  
Ray Ming
Keyword(s):  
Chromosome Number ◽  
Genome Size ◽  
Sex Chromosomes ◽  
Dna Content ◽  
Carica Papaya ◽  
Haploid Genome ◽  
Diploid Genome ◽  
Significant Difference ◽  
Heteromorphic Sex Chromosomes

Jarilla chocola is an herbaceous plant species that belongs to the Jarilla genus and the Caricaceae family. No information on chromosome number or genome size has been reported for J. chocola that confirms the occurrence of dysploidy events and explore the existence of heteromorphic sex chromosomes. Therefore, the total number of chromosomes of this species was determined by karyotyping and counting the number of chromosomes observed, and the genome size of female and male plants was estimated separately by flow cytometry. Results showed that J. chocola has eight pairs of chromosomes (2n = 2x = 16), and its chromosomes are classified as metacentric for five pairs, submetacentric for two pairs and telocentric for one pair. The nuclear DNA content (1C-value) in picograms and diploid genome size was estimated separately from female and male plants using two species as the standards, Phaseolus vulgaris (1C = 0.60 pg) and Carica papaya (1C = 0.325 pg), to look for the possible existence of heteromorphic sex chromosomes. C. papaya proved to be a better standard for the determination of J. chocola DNA content and diploid genome size. No significant difference on the DNA content was observed between female (1C = 1.02 ± 0.003 pg) and male (1C = 1.02 ± 0.008 pg) plants. The estimated genome size of J. chocola per haploid genome in base pairs was calculated from the obtained C-values. Results showed an estimated genome size per haploid genome of 1018.44 ± 3.07 Mb and 1022.08 ± 7.76 Mb for female and male plants, respectively. Due to the observed chromosome number and genome size, only the occurrence of one of two previously reported dysploidy events in Jarilla could be confirmed for J. chocola and no evidence of heteromorphic sex chromosomes was found. These results provide fundamental information of the J. chocola genome and will expedite investigation of sex chromosomes and genome evolution in this species, the Jarilla genus and the Caricaceae family

scholarly journals A new species of Urostreptus (Diplopoda, Spirostreptidae): description and chromossome number

2006 ◽  
Vol 96 (2) ◽  
pp. 209-212 ◽  
Author(s):  
Pedro H. B. Pierozzi ◽  
Carmem S. Fontanetti
Keyword(s):  
New Species ◽  
Chromosome Number ◽  
Constitutive Heterochromatin ◽  
Sao Paulo ◽  
São Paulo ◽  
Meiotic Analysis ◽  
Paulo State ◽  
C Banding ◽  
São Paulo State ◽  
A New Species

This work presents the description and chromosome number of Urostreptus atrobrunneus sp. nov. The genus until now had not been registered yet in the São Paulo State, Brazil. The meiotic analysis showed that the species presents 2n=24, XY. The C-banding revealed large blocks of constitutive heterochromatin and two heteromorphic chromosomal pairs, one of them corresponding to the sexual pair.

Hatchling Sex Ratios are Independent of Temperature in Field Nests of the Long-necked Turtle, Chelodina longicollis (Testudinata : Chelidae)

1991 ◽  
Vol 18 (2) ◽  
pp. 225 ◽  
Author(s):  
M Palmer-Allen ◽  
F Beynon ◽  
a Georges
Keyword(s):  
Sex Determination ◽  
Constant Temperature ◽  
Sex Chromosomes ◽  
Sex Ratios ◽  
Seasonal Trend ◽  
Temperature Dependent ◽  
Sharp Drop ◽  
Heteromorphic Sex Chromosomes ◽  
Chelodina Longicollis ◽  
Incubation Temperatures

Eastern long-necked turtles, Chelodina longicollis, are known to lack heteromorphic sex chromosomes and to lack temperature-dependent sex determination when incubated under constant conditions. This study determined whether sex ratios of hatchlings emerging from natural nests of C. longicollis were different from that expected from constant temperature experiments. Temperatures in the eight nests monitored varied considerably each day (by 1.7-12.6�C), with eggs at the top of the nest experiencing the greatest variation (mean range 9.0�C) and eggs at the bottom experiencing least variation (mean range 5.3�C). Temperatures experienced by the top and bottom eggs differed by as much as 5.7�C at any one time. No monotonic seasonal trend was evident, but rainfall caused a sharp drop in nest temperatures. Sex ratios in hatchlings from 14 field nests of C. longicollis did not differ significantly from 1:1, a result in agreement with previous studies conducted at constant incubation temperatures in the laboratory.

C-banded karyotypes of two Silene species with heteromorphic sex chromosomes

Genome ◽  
2002 ◽  
Vol 45 (2) ◽  
pp. 243-252 ◽  
Author(s):  
Aleksandra Grabowska-Joachimiak ◽  
Andrzej Joachimiak
Keyword(s):  
Sex Chromosomes ◽  
Sex Chromosome ◽  
Silene Latifolia ◽  
Silene Dioica ◽  
Dna Amount ◽  
Metaphase Chromosomes ◽  
X Chromosomes ◽  
C Banding ◽  
Y Chromosomes ◽  
Heteromorphic Sex Chromosomes

Mitotic metaphase chromosomes of Silene latifolia (white campion) and Silene dioica (red campion) were studied and no substantial differences between the conventional karyotypes of these two species were detected. The classification of chromosomes into three distinct groups proposed for S. latifolia by Ciupercescu and colleagues was considered and discussed. Additionally, a new small satellite on the shorter arm of homobrachial chromosome 5 was found. Giemsa C-banded chromosomes of the two analysed species show many fixed and polymorphic heterochromatic bands, mainly distally and centromerically located. Our C-banding studies provided an opportunity to better characterize the sex chromosomes and some autosome types, and to detect differences between the two Silene karyotypes. It was shown that S. latifolia possesses a larger amount of polymorphic heterochromatin, especially of the centromeric type. The two Silene sex chromosomes are easily distinguishable not only by length or DNA amount differences but also by their Giemsa C-banding patterns. All Y chromosomes invariably show only one distally located band, and no other fixed or polymorphic bands on this chromosome were observed in either species. The X chromosomes possess two terminally located fixed bands, and some S. latifolia X chromosomes also have an extra-centric segment of variable length. The heterochromatin amount and distribution revealed by our Giemsa C-banding studies provide a clue to the problem of sex chromosome and karyotype evolution in these two closely related dioecious Silene species.Key words: dioecious plant, Silene dioica, Silene latifolia, karyotype, sex chromosomes, heterochromatin, C-banding.

Polymerase chain reaction identification of a female-specific genetic marker in Arceuthobium americanum (lodgepole pine dwarf mistletoe) and its implications for Arceuthobium sex determination

Botany ◽  
2011 ◽  
Vol 89 (6) ◽  
pp. 369-377 ◽  
Author(s):  
Arvin Dwarka ◽  
Cynthia M. Ross Friedman ◽  
Mairi E. MacKay ◽  
Don Nelson
Keyword(s):  
Polymerase Chain Reaction ◽  
Sex Determination ◽  
Genetic Marker ◽  
Sex Chromosomes ◽  
Local Alignment ◽  
Chain Reaction ◽  
Male And Female ◽  
Arceuthobium Americanum ◽  
Polymerase Chain ◽  
Female Specific

In North America, the most widespread and speciose mistletoe is Arceuthobium M. Bieb. (dwarf mistletoes, Viscaceae), which is a dioecious parasite of conifers. Little is known about its sex determination system, and sex chromosomes have not been identified. A genetic marker for early gender discrimination in Arceuthobium would be useful in the study of sex ratios and sex determination. Here, random amplified polymorphic DNA analysis via the polymerase chain reaction (PCR) was used to investigate genetic differences between genders in Arceuthobium americanum Nutt. ex Engelm. collected near Kamloops, British Columbia and Bélair, Manitoba. A total of 196 10-mer primers were selected for analysis of DNA from isolated male and female A. americanum somatic tissue. A ∼900 bp female-specific DNA fragment was generated with primer OPB-18 (5′-CCACAGCAGT-3′). The fragment was cloned and sequenced. Using GenBank and the basic local alignment search tool alignment software, it was determined that the first ∼300 bp of this DNA sequence shared a high degree of similarity to transposable elements (76%) and a Y-chromosome (male) fragment (75%) in Silene latifolia Poir. Sequence-characterized amplified region primers were then designed. This study has generated an efficient molecular tool to differentiate male and female A. americanum while also providing evidence indicating that A. americanum may have homomorphic, possibly protoheteromorphic, sex chromosomes.

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