Clinal variation in autosomal satellite DNA clusters across a contact zone in Barker Frogs.

Contact zones between genetically divergent lineages offer a unique opportunity to explore gene flow and speciation dynamics. Because satellite DNAs (satDNAs) have high evolutionary rates, they may be useful for comparing related taxa and assessing contact zones. Here, we analyzed the distribution of chromosomal clusters of PcP190 satDNA across a contact zone between two distinct genetic lineages of a Neotropical species complex of frogs.

Sequencing of laser captured Z and W chromosomes of the tocantins paradoxical frog (Pseudis tocantins) provides insights on repeatome and chromosomal homology.

Pseudis tocantins is the only frog species of the hylid genus Pseudis that possesses highly heteromorphic sex chromosomes. Z and W chromosomes of Ps. tocantins differ in size, morphology, position of the nucleolar organizer region (NOR) and the amount and distribution of heterochromatin.

Rapid karyotypic evolution with high diploid number variation in a rare genus of bromeligenous frogs.

Bromeligenous is a leptodactylid genus closely related to and . The diploid number in all karyotyped species of these two latter genera is 24, which diverges from the modal diploid number (2 = 22) in the family. Here, we analyzed three species of and found karyotypes with 2 = 30, 2 = 32, and 2 = 36, diploid numbers that have not been reported in any other diploid leptodactylid species to date.

Comparative mapping of a new repetitive DNA sequence and chromosome region-specific probes unveiling rearrangements in an Amazonian frog complex.

The frog species exists in the Amazonian region and harbors heteromorphic Z and W chromosomes. A genetic lineage closely related to this species was recognized based on its mitochondrial DNA and RADseq-style markers, but its taxonomic status is still unclear and has been referred to as Lineage 1 of "". The heteromorphic sex chromosomes found in are not present in this lineage and which of its chromosome pairs is homologous to the sex chromosomes of remain to be elucidated as well as the role of such a karyotypic divergence in the evolution of these frogs.

Cytogenetic and genetic data support Crossodactylus aeneus Müller, 1924 as a new junior synonym of C. gaudichaudii Duméril and Bibron, 1841 (Amphibia, Anura).

The nominal anuran species Crossodactylus gaudichaudii Duméril and Bibron, 1841 and Crossodactylus aeneus Müller, 1924 are indistinguishable based on adult and larval morphology, being subject of taxonomic doubts. Here, we describe the karyotypes of C. gaudichaudii and C.

Signature of the Paleo-Course Changes in the São Francisco River as Source of Genetic Structure in Neotropical (Phyllomedusinae, Anura) Treefrog.

Historical processes that have interrupted gene flow between distinct evolutionary lineages have played a fundamental role in the evolution of the enormous diversity of species found in the Neotropical region. Numerous studies have discussed the role of geographic barriers and Pleistocene forest refugia in the diversification of the region's biodiversity. In the present study, we investigated the relative contribution of these different factors to the evolutionary history of , a Neotropical tree frog, which is amply distributed in the Brazilian Atlantic Forest and adjacent areas of the Caatinga biome.

Extensive Cryptic Diversity Within the - Species Complex (Amphibia, Anura) Revealed by Cytogenetic, Mitochondrial, and Genomic Markers.

Previous cytogenetic and phylogenetic analyses showed a high variability in the frog taxa and and suggested the presence of undescribed diversity in this species complex. Here, by 1) adding specimens from the Brazilian Amazon region, 2) employing sequence-based species delimitation approaches, and 3) including RADseq-style markers, we demonstrate that the diversity in the - species complex is even greater than previously suspected. Specimens from Viruá and Western Pará, located at the Guiana Amazonian area of endemism, were recovered as distinct from all previously identified lineages by the phylogenetic analyses based on mitochondrial DNA and RAD markers, a PCA from RAD data, and cytogenetic analysis.

Satellite DNA Mapping in (Hylidae, Pseudinae) Provides New Insights into Sex Chromosome Evolution in Paradoxical Frogs.

In the frog genus , previous works found a sex-linked heteromorphism of the PcP190 satellite DNA in the nucleolus organizer region (NOR)-bearing chromosome pairs of and , which possess a ZZ/ZW sex determination system. A pericentromeric inversion was inferred to have occurred during W chromosome evolution, moving a chromosomal cluster enriched by the PcP190 from the short arm (as observed in ) to the NOR-bearing long arm (as observed in ). However, whether such an inversion happened in or in the common ancestor of and remained unclear.

Atlantic West Ophiothrix spp. in the scope of integrative taxonomy: Confirming the existence of Ophiothrix trindadensis Tommasi, 1970.

We re-describe and confirm the validity of Ophiothrix trindadensis Tommasi, 1970 (Echinodermata: Ophiuroidea). This is a native species from Brazil, however it lacked a type series deposited in scientific collections. The recognition of O.

The mitochondrial genome of the endemic Brazilian paradoxical frog (Hylidae).

In this work, we present for the first time the mitochondrial genome of a paradoxical frog (). This genome is 15.56 kb, excluding the control region, and is similar in gene content to other hylid mitogenomes.

Comparative cytogenetics of tree frogs of the (Laurenti, 1768) group: conserved karyotypes and interstitial telomeric sequences.

The diploid number 2n = 30 is a presumed synapomorphy of Fitzinger, 1843, although a noticeable variation in the number of biarmed/telocentric chromosomes is observed in this genus. Such a variation suggests that several chromosomal rearrangements took place after the evolutionary origin of the hypothetical ancestral 30-chromosome karyotype; however, the inferred rearrangements remain unknown. Distinct numbers of telocentric chromosomes are found in the two most cytogenetically studied species groups of .

Chromosomal analysis of Physalaemus kroyeri and Physalaemus cicada (Anura, Leptodactylidae).

All the species of Physalaemus Fitzinger, 1826 karyotyped up until now have been classified as 2n = 22. The species of the Physalaemus cuvieri group analyzed by C-banding present a block of heterochromatin in the interstitial region of the short arm of pair 5. Physalaemus cicada Bokermann, 1966 has been considered to be a member of the Physalaemus cuvieri species group, although its interspecific phylogenetic relationships remain unknown.

Unraveling the Sex Chromosome Heteromorphism of the Paradoxical Frog Pseudis tocantins.

The paradoxical frog Pseudis tocantins is the only species in the Hylidae family with known heteromorphic Z and W sex chromosomes. The Z chromosome is metacentric and presents an interstitial nucleolar organizer region (NOR) on the long arm that is adjacent to a pericentromeric heterochromatic band. In contrast, the submetacentric W chromosome carries a pericentromeric NOR on the long arm, which is adjacent to a clearly evident heterochromatic band that is larger than the band found on the Z chromosome and justify the size difference observed between these chromosomes.

First insights on the retroelement Rex1 in the cytogenetics of frogs.

Background: While some transposable elements (TEs) have been found in the sequenced genomes of frog species, detailed studies of these elements have been lacking. In this work, we investigated the occurrence of the Rex1 element, which is widespread in fish, in anurans of the genus Physalaemus. We isolated and characterized the reverse transcriptase (RT)-coding sequences of Rex1 elements of five species of this genus.

Long-time evolution and highly dynamic satellite DNA in leptodactylid and hylodid frogs.

Background: Satellite DNA sequences are the most abundant components of heterochromatin and are repeated in tandem hundreds to thousands of times in the genome. However, the number of repeats of a specific satellite family can vary even between the genomes of related species or populations. The PcP190 satellite DNA family was identified in the genome of the leptodactylid frog Physalaemus cuvieri, which showed to be derived most likely from the 5S rDNA in an ancestral species.

Comparative cytogenetics of Physalaemus albifrons and Physalaemus cuvieri species groups (Anura, Leptodactylidae).

Recently, Physalaemus albifrons (Spix, 1824) was relocated from the Physalaemus cuvieri group to the same group as Physalaemus biligonigerus (Cope, 1861), Physalaemus marmoratus (Reinhardt & Lütken, 1862) and Physalaemus santafecinus Barrio, 1965. To contribute to the analysis of this proposition, we studied the karyotypes of Physalaemus albifrons, Physalaemus santafecinus and three species of the Physalaemus cuvieri group. The karyotype of Physalaemus santafecinus was found to be very similar to those of Physalaemus biligonigerus and Physalaemus marmoratus, which were previously described.

Comparative cytogenetic analysis of some species of the Dendropsophus microcephalus group (Anura, Hylidae) in the light of phylogenetic inferences.

Background: Dendropsophus is a monophyletic anuran genus with a diploid number of 30 chromosomes as an important synapomorphy. However, the internal phylogenetic relationships of this genus are poorly understood. Interestingly, an intriguing interspecific variation in the telocentric chromosome number has been useful in species identification.

Molecular organization and chromosomal localization of 5S rDNA in Amazonian Engystomops (Anura, Leiuperidae).

Background: For anurans, knowledge of 5S rDNA is scarce. For Engystomops species, chromosomal homeologies are difficult to recognize due to the high level of inter- and intraspecific cytogenetic variation. In an attempt to better compare the karyotypes of the Amazonian species Engystomops freibergi and Engystomops petersi, and to extend the knowledge of 5S rDNA organization in anurans, the 5S rDNA sequences of Amazonian Engystomops species were isolated, characterized, and mapped.

Heteromorphic Z and W sex chromosomes in Physalaemus ephippifer (Steindachner, 1864) (Anura, Leiuperidae).

Heteromorphisms between sex chromosomes are rarely found in anurans and sex chromosome differentiation is considered to be a set of recent recurrent events in the evolutionary history of this group. This paper describes for the first time heteromorphic sex chromosomes Z and W in the leiuperid genus Physalaemus. They were found in P.