scholarly journals Chromosome Numbers in Gymnosperms - An Update

2020 ◽  
Vol 69 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Shubhi Rastogi ◽  
Deepak Ohri
Keyword(s):  
Data Base ◽  
Sex Chromosomes ◽  
Chromosome Numbers ◽  
Present Report ◽  
B Chromosomes ◽  
Cytological Data ◽  
The Family ◽  
Heteromorphic Sex Chromosomes

AbstractThe present report is based on a cytological data base on 614 (56.0 %) of the total 1104 recognized species and 82 (90.0 %) of the 88 recognized genera of gymnosperms. Family Cycadaceae and many genera of Zamiaceae show intrageneric uniformity of somatic numbers, the genus Zamia is represented by a range of number from 2n=16-28. Ginkgo, Welwitschia and Gentum show 2n=24, 2n=42, and 2n=44 respectively. Ephedra shows a range of polyploidy from 2x-8x based on n=7. The family Pinaceae as a whole shows 2n=24except for Pseudolarix and Pseudotsuga with 2n=44 and 2n=26 respectively. Araucariaceae constantly shows 2n=26 while Podocarpaceae has a range of 2n=18-38. Sciadopityaceae and Cupressaceae are represented by 2n=20 and 2n=22 respectively. Taxaceae shows variable numbers of 2n=24, 36 and 22. Polyploidy is exceptional being represented by 8.0 % of the taxa studied. B-chromosomes have been studied in 31 taxa while heteromorphic sex chromosomes have been reported in some dioecious taxa.

A SYNOPSIS OF CYTOLOGICAL STUDIES IN GESNERIACEAE

2003 ◽  
Vol 60 (3) ◽  
pp. 425-447 ◽  
Author(s):  
M. MÖLLER ◽  
M. KIEHN
Keyword(s):  
Chromosome Numbers ◽  
New World ◽  
Web Search ◽  
Current Knowledge ◽  
Molecular Data ◽  
Generic Level ◽  
Old World ◽  
Basic Chromosome ◽  
Cytological Data ◽  
The Family

Our knowledge of cytological data published on members of the family Gesneriaceae is summarized and critically evaluated in the light of current taxonomic treatments and phylogenetic hypotheses. There are about 1000 published chromosome counts, covering 56% of the genera but only 18% of the species. In particular the New World tribes Beslerieae and Napeantheae and the Old World tribe Didymocarpeae are underexplored at generic level. In Gesneriaceae chromosome data are a valuable source of taxonomic characters. From our current knowledge of the phylogenetic relationships in the family we know that basic chromosome numbers in the New World subfamily Gesnerioideae appear to be rather conserved, but that a more complex pattern of genome evolution seems to be present among the Old World tribes. Both polyploidy and dysploid changes have played a significant role in the evolution of the family. However, the number of species for which both cytological and molecular data are available is at present too low to reach firm conclusions on ancestral basic chromosome numbers, particularly for the Old World group. To facilitate wider access to cytological data on the Gesneriaceae, a website has been developed (http://www.rbge.org.uk/rbge/web/search/index.jsp), which is introduced in this paper.

Karyotypic studies of some Australian Scincidae (Reptilia)

1973 ◽  
Vol 21 (1) ◽  
pp. 21 ◽  
Author(s):  
M King
Keyword(s):  
Sex Chromosomes ◽  
Chromosome Numbers ◽  
Species Differences ◽  
Chromosomal Evolution ◽  
Mitotic Chromosomes ◽  
Heteromorphic Sex Chromosomes

The mitotic chromosomes of nine species from five genera of the saurian family Scincidae are presented. Chromosome numbers and karyotypic morphology support the taxonomic subdivision of these lizards into the subfamilies Lygosominae (2n=30) and Scincinae (2n=32). A model for the chromosomal evolution of these species is postulated. Variability in chromosomal morphology is minimal though certain intergeneric and species differences were detected. Heteromorphic sex chromosomes were not observed.

The Chromosomes of 4 Genera of Possums From the Family Petauridae (Marsupialia, Diprotodonta)

1990 ◽  
Vol 38 (1) ◽  
pp. 33 ◽  
Author(s):  
JD Murray ◽  
SC Donnellan ◽  
GM Mckay ◽  
RH Rofe ◽  
PR Baverstock ◽  
...  
Keyword(s):  
Chromosome Number ◽  
Sex Chromosomes ◽  
Chromosome Numbers ◽  
Chromosomal Rearrangement ◽  
Diploid Chromosome Number ◽  
The Family ◽  
Relationship Of ◽  
The Relationship ◽  
Petaurus Australis

The standard and C-banded (four species) karyotypes of six species of the family Petauridae (Gymnobelideus leadbeateri, Petaurus australis, P. breviceps, P. norfolcensis, Dactylopsila trivirgata and Dactylonax palpator) are described. The G-banded karyotype of P. norfolcensis is also described. Gymnobelideus and Petaurus have diploid chromosome number of 22. All three species of Petaurus have a similar karyotype, consisting of biarmed autosomes and very small sex chromosomes, which differs from Gymnobelideus by a minimum of one chromosomal rearrangement of each autosome. Dactylopsila and Dactylonax have similar karyotypes with diploid chromosome numbers of 18. The relationship of these two genera to Petaurus is still uncertain but all members of this family differ from Pseudocheiridae in the small size of the 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.

scholarly journals Localization of Male-Specifically Expressed MROS Genes of Silene latifolia by PCR on Flow-Sorted Sex Chromosomes and Autosomes

Genetics ◽  
2001 ◽  
Vol 158 (3) ◽  
pp. 1269-1277
Author(s):  
Eduard Kejnovský ◽  
Jan Vrána ◽  
Sachihiro Matsunaga ◽  
Přemysl Souček ◽  
Jiří Široký ◽  
...  
Keyword(s):  
Sex Chromosomes ◽  
Silene Latifolia ◽  
Homology Search ◽  
X Chromosomes ◽  
Dioecious Plants ◽  
Flow Sorting ◽  
Heteromorphic Sex Chromosomes ◽  
Copy Gene ◽  
Melandrium Album ◽  
Pcr Products

Abstract The dioecious white campion Silene latifolia (syn. Melandrium album) has heteromorphic sex chromosomes, XX in females and XY in males, that are larger than the autosomes and enable their separation by flow sorting. The group of MROS genes, the first male-specifically expressed genes in dioecious plants, was recently identified in S. latifolia. To localize the MROS genes, we used the flow-sorted X chromosomes and autosomes as a template for PCR with internal primers. Our results indicate that the MROS3 gene is located in at least two copies tandemly arranged on the X chromosome with additional copy(ies) on the autosome(s), while MROS1, MROS2, and MROS4 are exclusively autosomal. The specificity of PCR products was checked by digestion with a restriction enzyme or reamplification using nested primers. Homology search of databases has shown the presence of five MROS3 homologues in A. thaliana, four of them arranged in two tandems, each consisting of two copies. We conclude that MROS3 is a low-copy gene family, connected with the proper pollen development, which is present not only in dioecious but also in other dicot plant species.

scholarly journals New Data on Organization and Spatial Localization of B-Chromosomes in Cell Nuclei of the Yellow-Necked Mouse Apodemus flavicollis

Cells ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1819
Author(s):  
Tatyana Karamysheva ◽  
Svetlana Romanenko ◽  
Alexey Makunin ◽  
Marija Rajičić ◽  
Alexey Bogdanov ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Sex Chromosomes ◽  
Interphase Nucleus ◽  
Spatial Organization ◽  
Three Dimensional ◽  
Dna Probes ◽  
B Chromosomes ◽  
Apodemus Flavicollis ◽  
Yellow Necked Mouse

The gene composition, function and evolution of B-chromosomes (Bs) have been actively discussed in recent years. However, the additional genomic elements are still enigmatic. One of Bs mysteries is their spatial organization in the interphase nucleus. It is known that heterochromatic compartments are not randomly localized in a nucleus. The purpose of this work was to study the organization and three-dimensional spatial arrangement of Bs in the interphase nucleus. Using microdissection of Bs and autosome centromeric heterochromatic regions of the yellow-necked mouse (Apodemus flavicollis) we obtained DNA probes for further two-dimensional (2D)- and three-dimensional (3D)- fluorescence in situ hybridization (FISH) studies. Simultaneous in situ hybridization of obtained here B-specific DNA probes and autosomal C-positive pericentromeric region-specific probes further corroborated the previously stated hypothesis about the pseudoautosomal origin of the additional chromosomes of this species. Analysis of the spatial organization of the Bs demonstrated the peripheral location of B-specific chromatin within the interphase nucleus and feasible contact with the nuclear envelope (similarly to pericentromeric regions of autosomes and sex chromosomes). It is assumed that such interaction is essential for the regulation of nuclear architecture. It also points out that Bs may follow the same mechanism as sex chromosomes to avoid a meiotic checkpoint.

A natural intergeneric hybrid of Gesneriaceae from Brazil

Phytotaxa ◽  
2021 ◽  
Vol 497 (2) ◽  
pp. 79-96
Author(s):  
ANDRÉA ONOFRE DE ARAUJO ◽  
MAURO PEIXOTO ◽  
CINTIA NEVES DE SOUZA ◽  
EDUARDO CUSTÓDIO GASPARINO ◽  
JULIANA TOLEDO FARIA ◽  
...  
Keyword(s):  
Chromosome Numbers ◽  
Pollen Morphology ◽  
Pollen Grains ◽  
Intergeneric Hybrid ◽  
Morphological Characters ◽  
Natural Hybrid ◽  
Pollen Data ◽  
Cytological Data ◽  
High Viability ◽  
Structural Abnormalities

A natural hybrid between Goyazia and Mandirola (Gloxiniinae, Gesneriaceae) from Cerrado (Brazil) is here described, supported by pollen morphology, cytological data and morphological characters. The microsporogenesis of Mandirola hirsuta and that of the hybrid were analyzed in order to evaluate the cytogenetic characteristics. The haploid chromosome numbers observed were n = 12 for M. hirsuta and n = 11, 13, 16 and 26 for the hybrid. Structural abnormalities (monads, dyads, triads and micronuclei) were observed at the final of the hybrid’s meiosis. High viability rates of the pollen were recorded for Goyazia and Mandirola (>90%) and low viability for the hybrid (34.7%). The pollen grains were acetolyzed, measured and photographed for pollen morphology analysis. Quantitative pollen data were analyzed through descriptive and multivariate statistics. The hybrid has intermediate pollen characteristics between G. petraea and M. hirsuta; it is more related to G. petraea by the measures of diameters and ectoapertures; it is more similar to M. hirsuta mainly regarding the microreticulum on the mesocolpium region. The hybrid and Mandirola share vegetative and flower size, while the colors of the hybrid are similar to Goyazia. Pollen morphology, cytological data and morphological characters brought clear evidence for the recognition of the intergeneric hybrid, which we named as Goydirola x punctata.

scholarly journals Karyotype Characterization of Nine Periwinkle Species (Gastropoda, Littorinidae)

Genes ◽  
2018 ◽  
Vol 9 (11) ◽  
pp. 517 ◽  
Author(s):  
Daniel García-Souto ◽  
Sandra Alonso-Rubido ◽  
Diana Costa ◽  
José Eirín-López ◽  
Emilio Rolán-Álvarez ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Chromosome Numbers ◽  
Gene Clusters ◽  
Chromosomal Mapping ◽  
Closely Related Species ◽  
Submetacentric Chromosome ◽  
The Family ◽  
Littorina Arcana

Periwinkles of the family Littorinidae (Children, 1834) are common members of seashore littoral communities worldwide. Although the family is composed of more than 200 species belonging to 18 genera, chromosome numbers have been described in only eleven of them. A molecular cytogenetic analysis of nine periwinkle species, the rough periwinkles Littorina arcana, L. saxatilis, and L. compressa, the flat periwinkles L. obtusata and L. fabalis, the common periwinkle L. littorea, the mangrove periwinkle Littoraria angulifera, the beaded periwinkle Cenchritis muricatus, and the small periwinkle Melarhaphe neritoides was performed. All species showed diploid chromosome numbers of 2n = 34, and karyotypes were mostly composed of metacentric and submetacentric chromosome pairs. None of the periwinkle species showed chromosomal differences between male and female specimens. The chromosomal mapping of major and minor rDNA and H3 histone gene clusters by fluorescent in situ hybridization demonstrated that the patterns of distribution of these DNA sequences were conserved among closely related species and differed among less related ones. All signals occupied separated loci on different chromosome pairs without any evidence of co-localization in any of the species.

Genetic and cytogenetic analysis of the fruit fly Rhagoletis cerasi (Diptera: Tephritidae)

Genome ◽  
2008 ◽  
Vol 51 (7) ◽  
pp. 479-491 ◽  
Author(s):  
Ilias Kounatidis ◽  
Nikolaos Papadopoulos ◽  
Kostas Bourtzis ◽  
Penelope Mavragani-Tsipidou
Keyword(s):  
Salivary Gland ◽  
Sex Chromosomes ◽  
Cytogenetic Analysis ◽  
Polytene Chromosomes ◽  
Fruit Fly ◽  
Pest Species ◽  
Heteromorphic Sex Chromosomes ◽  
Weak Points ◽  
Heterogametic Sex ◽  
Rhagoletis Cerasi

The European cherry fruit fly, Rhagoletis cerasi , is a major agricultural pest for which biological, genetic, and cytogenetic information is limited. We report here a cytogenetic analysis of 4 natural Greek populations of R. cerasi, all of them infected with the endosymbiotic bacterium Wolbachia pipientis . The mitotic karyotype and detailed photographic maps of the salivary gland polytene chromosomes of this pest species are presented here. The mitotic metaphase complement consists of 6 pairs of chromosomes, including one pair of heteromorphic sex chromosomes, with the male being the heterogametic sex. The analysis of the salivary gland polytene complement has shown a total of 5 long chromosomes (10 polytene arms) that correspond to the 5 autosomes of the mitotic nuclei and a heterochromatic mass corresponding to the sex chromosomes. The most prominent landmarks of each polytene chromosome, the “weak points”, and the unusual asynapsis of homologous pairs of polytene chromosomes at certain regions of the polytene elements are also presented and discussed.

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