scholarly journals Sex‐related differences in aging rate are associated with sex chromosome system in amphibians

Evolution ◽  
2021 ◽  
Author(s):  
Hugo Cayuela ◽  
Jean‐François Lemaître ◽  
Jean‐Paul Léna ◽  
Victor Ronget ◽  
Iñigo Martínez‐Solano ◽  
...  
Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 661
Author(s):  
Ikuo Miura ◽  
Foyez Shams ◽  
Si-Min Lin ◽  
Marcelo de Bello Cioffi ◽  
Thomas Liehr ◽  
...  

Translocation between sex-chromosomes and autosomes generates multiple sex-chromosome systems. It happens unexpectedly, and therefore, the evolutionary meaning is not clear. The current study shows a multiple sex chromosome system comprising three different chromosome pairs in a Taiwanese brown frog (Odorrana swinhoana). The male-specific three translocations created a system of six sex-chromosomes, ♂X1Y1X2Y2X3Y3 -♀X1X1X2X2X3X3. It is unique in that the translocations occurred among three out of the six members of potential sex-determining chromosomes, which are known to be involved in sex-chromosome turnover in frogs, and the two out of three include orthologs of the sex-determining genes in mammals, birds and fishes. This rare case suggests sex-specific, nonrandom translocations and thus provides a new viewpoint for the evolutionary meaning of the multiple sex chromosome system.


2006 ◽  
Vol 4 (1) ◽  
pp. 93-97 ◽  
Author(s):  
Renildo Ribeiro de Oliveira ◽  
Issakar Lima Souza ◽  
Paulo Cesar Venere

The neotropical freshwater systems have a high number of catfish species (Siluriformes), and many of those are denominated "cascudos" in Brazil. Cytogenetic data about three "cascudos" species fished in the rio Araguaia are described in the present study. The Pterygoplichthys joselimaianus showed 2n=52, with 28 metacentrics (M) chromosomes, 16 submetacentrics (SM) and 8 subtelocentrics/acrocentrics (ST/A) in both sexes. Hemiancistrus spinosissimus showed 2n=52, with karyotype formulae 26M+22SM+4ST, in both sexes. Hemiancistrusspilomma also showed 2n=52, but in this species a ZZ/ZW sex chromosome system (25M+21SM+6ST in females and 24M+22SM+6ST in males) was observed. The cells from H. spinosissimus and P. joselimaianus showed one chromosome pair bearing Ag-NORs, while in the H. spilomma three chromosome pairs bearing Ag-NORs were detected. The data showed in this work reveal particular chromosomal characteristics, important for a good recognition of both Hemincistrus species, and also show the importance of the insertion of cytogenetic data on taxonomic phylogenetic studies.


2012 ◽  
Vol 35 (4) ◽  
pp. 770-776 ◽  
Author(s):  
Elisangela Bellafronte ◽  
Michelle Orane Schemberger ◽  
Roberto Ferreira Artoni ◽  
Orlando Moreira Filho ◽  
Marcelo Ricardo Vicari

2021 ◽  
Vol 15 (4) ◽  
pp. 467-505
Author(s):  
Dmitry A. Gapon ◽  
Valentina G. Kuznetsova ◽  
Anna Maryańska-Nadachowska

A new species, Rhaphidosoma paganicumsp. nov. (Heteroptera: Reduviidae: Harpactorinae: Rhaphidosomatini), is described from the Dry Zone of Myanmar. It is the fifth species of Rhaphidosoma Amyot et Serville, 1843, known from the Oriental Region, and the first record of the genus for Myanmar and Indochina. The structure of the external and internal terminalia of the male and female is described and illustrated in detail. The completely inflated endosoma is described for the first time in reduviids. The complex structure of the ductus seminis is shown; it terminates with a voluminous seminal chamber which opens with a wide secondary gonopore and may be a place where spermatophores are formed. The new species is compared with all congeners from the Oriental Region and Western Asia. It is characterised by the absence of distinct tubercles on the abdominal tergites of the male, the presence only two long tubercles and small rounded ones on the abdominal tergites VII and VI, respectively, in the female, the presence of short fore wing vestiges which are completely hidden under longer fore wing vestiges, and other characters. In addition to the morphological description, an account is given of the male karyotype and the structure of testes of Rh. paganicumsp. nov. and another species of Harpactorinae, Polididus armatissimus Stål, 1859 (tribe Harpactorini). It was found that Rh. paganicumsp. nov. has a karyotype comprising 12 pairs of autosomes and a multiple sex chromosome system (2n♂=24A+X1X2X3Y), whereas P. armatissimus has a karyotype comprising five pairs of autosomes and a simple sex chromosome system (2n♂=10A+XY). The males of these species were found to have seven and nine follicles per testis, respectively. FISH mapping of 18S ribosomal DNA (major rDNA) revealed hybridisation signals on two of the four sex chromosomes (Y and one of the Xs) in Rh. paganicumsp. nov. and on the largest pair of autosomes in P. armatissimus. The presence of the canonical “insect” (TTAGG)n telomeric repeat was detected in the chromosomes of both species. This is the first application of FISH in the tribe Raphidosomatini and in the genus Polididus Stål, 1858.


2006 ◽  
Vol 66 (1b) ◽  
pp. 205-210 ◽  
Author(s):  
G. G. Born ◽  
L. A. C. Bertollo

Specimens of Hoplias malabaricus from Lagoa Carioca, an isolated lake of the Rio Doce State Park (state of Minas Gerais, Brazil), were cytogenetically studied. The diploid number was found to be constant, i.e., 2n = 42 chromosomes, although two karyotypic forms were found: karyotype A, characterized by 22M + 20SM chromosomes, observed only in a male specimen, and karyotype B, characterized by 24M + 16SM + 2ST and 24M + 17SM + 1ST chromosomes in female and male specimens, respectively. This sex difference found in karyotype B is related to an XX/XY sex chromosome system. Another female specimen of H. malabaricus, also carrying karyotype A, had previously been found in the same lake. The available data indicate that two sympatric cytotypes of H. malabaricus exist in the Lagoa Carioca, with cytotype A occurring at a lower frequency and differing from cytotype B by undifferentiated sex chromosomes.


2021 ◽  
Vol 15 (2) ◽  
pp. 89-99
Author(s):  
Ricardo Firmino de Sousa ◽  
Paulo Cesar Venere ◽  
Karina de Cassia Faria

Dermanura Gervais, 1856 is represented by small frugivorous bats of the Stenodermatinae subfamily. The taxonomy of this group presents controversies and has been subject to changes, especially since the morphological characters evaluated have left gaps that are difficult to fill regarding good species characterization. Previous studies performed in Dermanura cinerea Gervais, 1856 found that the karyotype of this species has a diploid number of chromosomes equal to 30 and 56 autosomal arms. The objective of the present study was to describe, for the first time, the karyotypes of the species Dermanura anderseni (Osgood, 1916) and Dermanura gnoma (Handley, 1987) based on classical cytogenetic markers. For both species, the diploid number found was 2n = 30 and NFa = 56. Two pairs of chromosomes showed markings of the nucleolus organizing regions (AgNORs) in the species D. anderseni and only one pair in D. gnoma, differing from what has already been described for D. cinerea. The two species analyzed here also showed differences in the sex chromosome system, with D. gnoma showing a neo-XY type system while in D. anderseni the classic XY sexual system was observed. In both species, visualization of the constitutive heterochromatin occurred in the pericentromeric region of all chromosomes, as well as in the short arms of the subtelocentric chromosomes. The present work represents an important expansion of karyotypic information for the subfamily Stenodermatinae, bringing chromosomal features that are possible to use in the taxonomic implications of the group.


2021 ◽  
Vol 16 (1) ◽  
pp. 37-44
Author(s):  
Marcello Mezzasalma ◽  
Gaetano Odierna

The smooth snake Coronella austriaca is a widespread Palearctic colubrid species. The species has been the subject of several molecular and phylogeographic studies which highlighted the occurrence of distinct genetic lineages in different areas of the species distribution, but scarce cytogenetic data are currently available on the species. In this paper we present a molecular and karyological study performed with several banding, staining methods and NOR-FISH on samples of C. austriaca from different geographical areas (Italy and Greece) of the species distribution. The molecular and phylogenetic analysis unambiguously placed the studied samples in different clades with a clear geographical pattern. The karyotype of the two female samples studied was composed of 2n = 36 chromosomes with 16 macro- and 20 microchromosomes and a mix of plesiomorphic and derivate chromosome features. All macrochromosomes were biarmed with the exception of pair 5 that was telocentric. NORs were detected on a microchromosome pair. In both females, the pair 4 was heteromorphic (and completely heterochromatic after C-banding in the Italian female), representing the first report of a ZZ/ZW sex chromosome system with female heterogamety in C. austriaca. In addition, the W chromosome showed a different morphology between the two female studied (submetacentric and subtelocentric), highlighting the occurrence of a chromosomal diversification among distinct geographical areas of the species distribution and further supporting that the species contains different diverging evolutionary clades.


2019 ◽  
Vol 13 (1) ◽  
pp. 87-93 ◽  
Author(s):  
Bruno Cansanção Silva ◽  
Lucas Henrique Bonfim Souza ◽  
Juliana Chamorro-Rengifo ◽  
Douglas Araujo

Phaneropterinae is the largest subfamily of Tettigoniidae, distributed across the globe. There are few cytogenetic studies regarding this group, as in the case of the genus group Aniarae, which represents only two karyotyped species. The current study aims to analyze cytogenetically three species of Hyperophora Brunner von Wattenwyl, 1878 from Brazil. The male diploid number of Hyperophoraminor Brunner von Wattenwyl, 1891 and Hyperophoramajor Brunner von Wattenwyl, 1878 is 2n♂= 31, whereas Hyperophorabrasiliensis Brunner von Wattenwyl, 1878 has shown 2n♂= 29. These three species possess an X0 sex chromosome system and telo/acrocentric chromosome morphology. The only species found in the Pantanal biome, H.brasiliensis, can be chromosomally distinguished from the Cerrado biome species H.major and H.minor, due to the difference in chromosome number (2n♂= 29 and 2n♂= 31, respectively).


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