Abstract Introduction and objective: To demonstrate the value of the axial plane of the posterior complex, as a clue for the antenatal detection of synthelencephaly, a variant of holoprosencephaly. Method: All patients diagnosed with syntelencephaly evaluated since 2008 were included. In all cases, clinical, neurosonography (NSG), magnetic resonance imaging (MRI) and genetic data were recorded. Results: Four cases were diagnosed in the second trimester and in all of them a genetic study and MRI were performed. Three had extra-CNS anomalies in their evolution and two of them chromosomal anomalies, one of them incompatible with extrauterine life. Neuroimaging findings described for this condition were detected by NSG, with an excellent correlation with MRI, whether the latter was performed in the fetal or postnatal period. Conclusion: The prenatal diagnosis of holoprosencephaly variants is difficult, considering the existence of a more limited medial fusion than in the classical forms. The present study demonstrates the usefulness of the posterior complex plane for the diagnostic suspicion of synthelencephaly.

Resumen Introducción y objetivo: Demostrar el valor del plano axial del complejo posterior, como apoyo a la detección antenatal de sintelencefalia, variante de holoprosencefalia. Método: Se incluyeron todas las pacientes con diagnóstico de sintelencefalia evaluadas desde el año 2008. En todos los casos se consignaron los datos clínicos, de neurosonografía (NSG), de resonancia magnética (RM) y genética. Resultados: Cuatro casos fueron diagnosticados en el segundo trimestre y en todos se realizó estudio genético y RM. Tres tuvieron en su evolución anomalías extra-SNC y dos de ellos alteraciones cromosómicas, una de ellas incompatible con la vida extrauterina. Lo hallazgos descritos en neuroimagen para esta afección fueron detectados en la NSG, con una excelente correlación con RM, ya fuera esta última realizada en periodo fetal o posnatal. Conclusión: El diagnóstico prenatal de variantes de holoprosencefalia es difícil, considerando la existencia de una fusión medial más acotada que en las formas clásicas. El presente estudio demuestra la utilidad del plano del complejo posterior para la sospecha diagnóstica de sintelencefalia.

Resumo Padrões cromossômicos são ferramentas valiosas em abordagens evolutivas. Apesar da notável expansão dos dados citogenéticos dos peixes, eles ainda são altamente deficientes para as espécies de águas oceânicas profundas, incluindo os membros da família Gempylidae. Espécies desta família são comercialmente importantes, compostas por predadores meso e bentopelágicos, cujas informações disponíveis sobre seu estilo de vida e padrões genéticos são muito limitadas. Este estudo apresenta os primeiros dados cromossômicos de duas espécies circumglobais desta família, Ruvettus pretiosus e Promethichthys prometheus, do Arquipélago de São Pedro e São Paulo. Foram utilizadas análises convencionais, coloração cromossômica com fluorocromos base-específicos e hibridização in situ por fluorescência (FISH) para o mapeamento de diferentes classes de DNA repetitivos. Ambas as espécies possuem 2n = 48 cromossomos, mas diferem significativamente quanto à fórmula cariotípica (FN = 50 e FN = 84). Os sítios 18S DNAr/Ag-RON e 5S DNAr têm um arranjo bi-telomérico sintênico em R. pretiosus, mas uma distribuição independente em P. prometheus. Os elementos transponíveis têm dispersão semelhante em ambas as espécies, enquanto os microssatélites estão agrupados nas regiões centroméricas e terminais de alguns cromossomos. Vale ressaltar que apesar da conservação do 2n basal dos Percomorpha, uma acentuada diversificação macro e microestrutural, mediada principalmente por inversões pericêntricas, diferencia os cariótipos das espécies, apontando para uma trajetória cromossômica particular dos gempilídeos entre os peixes marinhos. evolutivas profundas Gempylidae importantes bentopelágicos limitadas prometheus Paulo convencionais baseespecíficos base específicos FISH (FISH repetitivos n 4 cromossomos 5 84. 84 . 84) S DNAr/AgRON DNArAgRON DNAr/Ag RON Ag bitelomérico bi telomérico R P Percomorpha microestrutural pericêntricas marinhos 8 AgRON DNArAg

Abstract Chromosomal patterns are valuable tools in evolutionary approaches. Despite the remarkable expansion of fish cytogenetic data, they are still highly deficient concerning deep oceanic species, including the Gempylidae snake mackerels. The snake mackerels are important commercial species composed by meso- and bento-pelagic predators with very limited information available about their lifestyle and genetics patterns. This study presents the first chromosomal data of two circumglobal species of this family, Ruvettus pretiosus and Promethichthys prometheus, from the São Pedro and São Paulo Archipelago. Conventional analyses, chromosomal staining with base-specific fluorochromes, and fluorescence in situ hybridization (FISH) for mapping of repetitive DNA classes were used. Both species have 2n = 48 chromosomes, but they highly differ regarding the karyotype formula (FN = 50 and FN = 84). The 18S rDNA/Ag-NOR and the 5S rDNA sites have a syntenic bi-telomeric array in R. pretiosus, but an independent distribution in P. prometheus. The transposable elements are dispersed, while the microsatellites are also clustered in the centromeric and terminal regions of some chromosomes. It is noteworthy that despite the 2n conservation, a marked macro and microstructural diversifications, mainly mediated by pericentric inversions, differentiates the karyotypes of the species, pointing to a particular chromosomal trajectory of the gempylids among marine fish. approaches meso bentopelagic bento pelagic family prometheus Archipelago analyses basespecific base specific fluorochromes FISH (FISH used n 4 chromosomes 5 84. 84 . 84) S rDNA/AgNOR rDNAAgNOR rDNA/Ag NOR Ag bitelomeric bi telomeric R P dispersed conservation diversifications inversions 8 AgNOR rDNAAg

Abstract Centromochlinae is a widely diverse subfamily with more than 50 species and several taxonomic conflicts due to morphological similarity between Tatia and Centromochlus species. However, cytogenetic studies on this group have been limited to only four species so far. Therefore, here we present the karyotype of Centromochlus schultzi from the Xingu River in Brazil using classic cytogenetic techniques, physical mapping of the 5S and 18S rDNAs, and telomeric sequences (TTAGGG)n. The species had 58 chromosomes, simple NORs and 18S rDNA sites. Heterochromatic regions were detected on the terminal position of most chromosomes, including pericentromeric and centromeric blocks that correspond to interstitial telomeric sites. The 5S rDNA had multiple sites, including a synteny with the 18S rDNA in the pair 24st, which is an ancestral feature for Doradidae, sister group of Auchenipteridae, but appears to be a homoplastic trait in this species. So far, C. schultzi is only the second species within Centromochlus to be karyotyped, but it has already presented characteristics with great potential to assist in future discussions on taxonomic issues in the subfamily Centromochlinae, including the first synteny between rDNAs in Auchenipteridae and also the presence of heterochromatic ITSs that could represent remnants of ancient chromosomal fusions. 5 However far Therefore techniques S TTAGGGn. TTAGGGn TTAGGG n. n (TTAGGG)n chromosomes sites 24st st Doradidae C karyotyped fusions

RESUMO Este estudo tem como objetivo realizar uma análise citogenética em quatro espécies de felinos sul-americanos: a onça-pintada (Panthera onca), a suçuarana (Puma concolor), o gato-do-mato-pequeno (Leopardus wiedii) e o gato doméstico (Felis catus). Descobriu-se que a onça-pintada e a suçuarana diferem principalmente em seu número fundamental de cromossomos. Além disso, notou-se uma diferença morfológica em um par de cromossomos entre a onça-pintada e o gato doméstico. Isso nos sugere que, ao longo da evolução, houve uma inversão pericêntrica em um par de cromossomos do grupo B4, que passou a fazer parte do grupo A na onça-pintada. Quando se analisou a suçuarana, observou-se a presença de um quarto par de cromossomos no grupo E, juntamente com uma deleção no grupo F. Isso sugere que, ao longo de sua evolução, a suçuarana também passou por uma inversão pericêntrica. A principal diferença entre o gato-do-mato-pequeno e o gato doméstico reside na ausência de cromossomos no grupo F devido à fusão de dois pares de cromossomos telocêntricos. Além disso, notou-se a presença de um par adicional de cromossomos no grupo C no gato-do-mato-pequeno. Outro aspecto interessante do estudo foi a localização das regiões organizadoras nucleolares (NOR) nos cromossomos. Descobriu-se que, tanto na onça-pintada quanto na suçuarana, as NORs estão localizadas no braço curto do par de cromossomos E1. Para elucidar a origem de outros pares de cromossomos, foram empregadas técnicas de bandamento cromossômico, o que permitiu entender melhor a evolução do par C3 no gênero Leopardus e do par E4 no gênero Puma. sulamericanos sul americanos sul-americanos onçapintada onça pintada Panthera onca, onca , onca) Puma concolor, concolor concolor) gatodomatopequeno mato pequeno wiedii Felis catus. catus . catus) Descobriuse Descobriu disso notouse notou B4 B onçapintada. pintada. observouse observou E telocêntricos gatodomatopequeno. pequeno. NOR (NOR E1 cromossômico

ABSTRACT This study aims to conduct a cytogenetic analysis on four South American feline species: the jaguar (Panthera onca), the puma (Puma concolor), the ocelot (Leopardus wiedii), and the domestic cat (Felis catus). We discovered that the jaguar and the puma mainly differ in their fundamental number of chromosomes. Furthermore, we observed a morphological difference in a pair of chromosomes between the jaguar and the domestic cat. This suggests that, over the course of evolution, there was a pericentric inversion in a pair of B4 group chromosomes, leading them to become part of the A group in the jaguar. When analyzing the puma, we noticed the presence of a fourth pair of chromosomes in the E group, along with a deletion in the F group. Additionally, we observed the presence of an additional pair of chromosomes in the C group in the ocelot. Another interesting aspect of the study was the location of nucleolar organizer regions (NORs) on the chromosomes. To elucidate the origin of other chromosome pairs, we employed chromosomal banding techniques, allowing us to better understand the evolution of the C3 pair in the Leopardus genus and the E4 pair in the Puma genus. species Panthera onca, onca , onca) concolor, concolor concolor) wiedii, wiedii wiedii) Felis catus. catus . catus) Furthermore B Additionally NORs (NORs pairs techniques

Resumo O gênero Tetranematichthys possui apenas três espécies, e nenhuma delas tinha sido submetida a análises citogenéticas. Assim, este estudo traz pela primeira vez a análise de Tetranematichthyswallacei, coletado no Igarapé Apaú, bacia do rio Guamá, cidade de Castanhal, estado do Pará, Brasil. O número diploide de 52 cromossomos (32m+18sm+2st, NF = 104) foi encontrado em ambos os sexos, com heterocromatina predominantemente terminal e algumas intersticiais. A sequência telomérica foi observada exclusivamente em regiões terminais. Os sítios de 18S rDNA foram encontrados no par 17sm de todos os exemplares e em apenas um dos homólogos do par 7 em três exemplares. Os sítios de 5S rDNA foram encontrados nos pares 8m e 10m. Tetranematichthyswallacei possui algumas características que dignas de quanto à sua posição filogenética atual, incluindo uma provável redução no número diploide. Além disso, T.wallacei compartilha com Tympanopleuraatronasus o 18S rDNA alocado no braço longo de um grande cromossomo sm (primeiro par), mas não compartilha com Ageneiosus o primeiro par m grande com evidências de fusão, como observado em Ageneiosus inermis. Os dados cromossômicos gerados para T. wallacei, juntamente com os dados dos outros dois táxons de Ageneiosini estudados anteriormente, reforçam propostas de estudos baseados em morfologia que sugerem que a tribo representa o clado mais diferenciado dentro da família. espécies citogenéticas Assim Apaú Guamá Castanhal Pará Brasil 5 32m+18sm+2st, 32m18sm2st msmst 32m 18sm 2st st (32m+18sm+2st 104 sexos intersticiais terminais S 10m atual disso Twallacei T wallacei par, , par) fusão inermis anteriormente família 32m+18sm+2st 10 1

Abstract The genus Tetranematichthys has only three species, and none of them have undergone cytogenetic analyses. Therefore, this study brings for the first time the analysis of Tetranematichthys wallacei, collected from the Igarapé Apaú, Guamá River basin, municipality of Castanhal, Pará State, Brazil. The diploid number found was 52 chromosomes (32m+18sm+2st, NF = 104), in both sexes, with predominantly terminal and some interstitial heterochromatin. Telomeric sequences were observed exclusively in terminal regions. The 18S rDNA sites were found on pair 17sm of all specimens and in only one of the homologous of pair 7 in three specimens. The 5S rDNA sites were found in pairs 8m and 10m. Tetranematichthys wallacei exhibits characteristics worthy of attention regarding its current phylogenetic position, including a probable diploid number reduction. Additionally, it shares with Tympanopleura atronasus the 18S rDNA allocated in the long arm of a large sm chromosome (first pair) but does not share with Ageneiosus the large first m pair with evidence of fusion, as observed in Ageneiosus inermis. The chromosomal data generated for T. wallacei, along with the data from the other two previously studied Ageneiosini taxa, reinforces proposals from morphology-based studies suggesting that the tribe represents the most distinct clade within the family. species analyses Therefore Apaú basin Castanhal State Brazil 5 32m+18sm+2st, 32m18sm2st msmst 32m 18sm 2st st (32m+18sm+2st 104, 104 , 104) sexes heterochromatin regions S 10m position reduction Additionally fusion inermis T taxa morphologybased morphology based family 32m+18sm+2st 10 1

Abstract The genus Stylosanthes has economic importance in semi-arid regions and requires studies that reveal complex relationships between species involving different ploidies. The aim of this study was to cytogenetically investigate accessions of Stylosanthes identified as S. scabra, in order to properly identify the number, morphology, and pattern of distribution of heterochromatin, analyzing the karyological variability of these species. Accessions with 2n=40 and 2n=20 were identified, exhibiting semi-reticulate interphase nuclei, symmetric karyotype, varied morphology, with differences in average chromosomal size, and genome length. The analysis with the fluorochromes chromomycin (CMA) and 4’,6-diamidino-2-phenylindole (DAPI) allowed the visualization of two CMA+ blocks in the subterminal region of the short arm in all accessions, and DAPI+/CMA- bands in S. scabra accessions. This suggests that not only chromosomal rearrangements, but also changes in the composition of heterochromatin, may have occurred during the speciation of this genus, and that S. scabra may be undergoing chromosomal evolution based on the observed karyological differences. In addition to the ploidy level, the distribution pattern of CMA+ heterochromatin reinforces the separation between S. scabra and S. seabrana. Thus, this genus represents an interesting group of plants for further studies on the content and quantity of repetitive and non-repetitive DNA sequences. semiarid semi arid ploidies S number morphology 2n40 n 2n 40 2n=4 2n20 20 2n=2 semireticulate reticulate nuclei karyotype size length CMA (CMA 4,6diamidino2phenylindole 46diamidino2phenylindole diamidinophenylindole 4 ,6 diamidino 2 phenylindole 6 DAPI (DAPI DAPI+/CMA DAPICMA rearrangements level seabrana Thus nonrepetitive non sequences 2n4 2n= 2n2 6diamidino2phenylindole ,

RESUMO: Physalis peruviana L. (fisális) apresenta grande potencial econômico devido ao sabor diferenciado de seus frutos. A produtividade dos pomares brasileiros é baixa em função do número limitado de variedades ou cultivares disponíveis. O principal entrave na seleção de genótipos superiores é a falta de informação sobre a variabilidade genética dentro e entre as populações de fisális e, possivelmente, a base genética limitada das mesmas, que pode ser explicada pelos processos evolutivos, de domesticação e de seleção das populações naturais ou artificiais. A fisális cultivada atualmente no Brasil é tetraploide e tal poliploidia pode ter levado ao isolamento reprodutivo da espécie, o qual impede a ocorrência de hibridação intraespecífica. As populações cultivadas provêm de um pool genético comum e, além disso, sofreram um longo processo de domesticação e seleção realizadas empiricamente pelos agricultores. Porém, na Colômbia e em outros países andinos existem populações silvestres que exibem diversidade genética que, embora sejam fundamentais para a conservação da espécie, apresentam baixo potencial para o desenvolvimento de genótipos com características agronômicas superiores. A fim de criar e ampliar a variabilidade genética de fisális, os melhoristas tem empregado várias estratégias incluindo a indução de mutação, a duplicação cromossômica e a hibridação inter e intraespecífica. Além disso, a produção de linhagens duplo-haploides a partir da cultura de anterasin vitro vem demonstrando bons resultados para a seleção de híbridos. Os genótipos mutantes e/ou híbridos obtidos através dos métodos citados em associação com os de seleção genômica ampla podem gerar cultivares com características agronômicas superiores.

ABSTRACT: Physalisperuviana L. (physalis) has significant economic potential by virtue of the unique flavor of its fruit. However, the productivity of Brazilian plantations is low because of the limited number of varieties or cultivars available. The main obstacle in the selection of superior genotypes is the lack of information about genetic variability within- and between- populations and limited genetic basis that has likely resulted from evolutionary, domestication and selection processes of the natural or artificial populations. Physalis currently cultivated in Brazil is tetraploid, and such polyploidy may have led to the reproductive isolation of the species, preventing the occurrence of intraspecific hybridization. Moreover, cultivated populations derive from a common gene pool and have undergone a long process of domestication and selection carried out empirically by farmers. In Colombia and other Andean countries there are wild populations that exhibit genetic diversity which; although, fundamental for the conservation of the species, have low potential for the development of genotypes with superior agronomic traits. In order to create and expand the genetic variability of physalis, breeders have employed various strategies including induction of mutation, chromosome duplication, and interspecific and intraspecific hybridization. Furthermore, the production of double haploid lines from in vitro anther cultures has shown good results in the selection of hybrids. The mutant genotypes and/or hybrids obtained using these methods in association with those of wide genomic selection can generate cultivars with superior agronomic traits.

Abstract O-methyltransferases (OMTs) are a group of enzymes involved in several fundamental biological processes in plants, including lignin biosynthesis, pigmentation, and aroma production. Despite the intensive investigation of the role of OMTs in plant secondary metabolism, the evolution and diversification of this gene family in Solanaceae remain poorly understood. Here, we conducted a genome-wide survey of OMT genes in six Solanaceae species, reconstructing gene phylogenetic trees, predicting the potential involvement in biological processes, and investigating the exon/intron structure and chromosomal location. We identified 57 caffeoyl-CoA OMTs (CCoAOMTs) and 196 caffeic acid OMTs (COMTs) in the studied species. We observed a conserved gene block on chromosome 2 that consisted of tandem duplicated copies of OMT genes. Our results suggest that the expansion of the OMT gene family in Solanaceae was driven by whole genome duplication, segmental duplication, and tandem duplication, with multiple genes being retained by neofunctionalization and subfunctionalization. This study represents an essential first step in unraveling the evolutionary history of OMTs in Solanaceae. Our findings deepen our understanding of the crucial role of OMTs in several biological processes and highlight their significance as potential biotechnological targets.

Abstract The tribe Serrasalmini is a diverse group with paraphyletic genera and taxonomic uncertainties. Several studies have been carried out in this group of fish in order to understand this problem, including the cytogenetic approach. In this study, three species of a clade of Serrasalmini were characterized cytogenetically - Pristobrycon striolatus, Catoprion absconditus and Pygopristis denticulatus. The three species presented diploid number (2n) equal to 62 chromosomes, of one and two arms, with karyotypic formulas and species-specific fundamental numbers. Heterochromatin is centromeric and terminal (bi-telomeric) in most chromosomes, with a conspicuous interstitial block at pair 1 (m) in all three species. The nucleolar organizer regions were multiple and C-band positive, and their location was confirmed via 18S ribosomal DNA mapping; however, with additional sites. The 5S rDNA was located in interstitial region of long arm of pair 1 (m), in the three species (homeologous). Moreover, we observed synteny between 18S and 5S in the species C. absconditus and P. denticulatus, which, according to fiber-FISH, are interspersed. Thus, the maintenance of 2n (62) evidences the diversification of chromosomal formulas within the clade by non-Robertsonian rearrangements and reflects the paraphyly of the related species.

Abstract Rodentia has a high species number and chromosomal variability. The South American genus Akodon is one of the most speciose muroids, with more than 40 species included in several species groups. Here, we characterize cytogenetically specimens of Akodon from central-western Argentina. Subsequently, we reviewed and analyzed the cytogenetic data for this genus, build a phylogeny and mapped chromosome changes to interpret its evolution. Specimens of A. dolores from central-western Argentina have 2n=42-44/FNa=44 (46, 48) due to a Robertsonian rearrangement. Our data expand the distribution range known for this polymorphism and confirm its geographic structure. Other specimens had 2n=40/FNa=40, representing populations of A. oenos, A. polopi, and A. spegazzinii. All karyotypes have a low amount of heterochromatin, concentrated in centromeres and sex chromosomes, as in other rodents. The complement with 2n=40/FNa=40 is the most frequent in Akodon and is shared by most species in some groups. Chromosome numbers are very diverse. The FNa shows less variability; FNa=42 was recovered as ancestral, excluding A. mimus, which was connected at the base of the Akodon tree and has FNa=44. This indicates a complex chromosome evolution in Akodon, and suggests that reductions and increases in the 2n and FNa evolved independently in some lineages.

Abstract Deuterodon is a genus of the subfamily Stethaprioninae, a group of Neotropical fish known as tetras. Deuterodon hastatus represents a species complex, which is supported by cytogenetic and molecular data. In this study, we show the results of comparative evolutionary analyses of the ATP synthase subunit 6 gene in four Deuterodon species, in addition to ribosomal markers (18S rDNA and 5S rDNA), of a new population of the D. hastatus species complex from the Angra dos Reis/RJ region. The study population comprised a new cytotype, which we refer to as cytotype D, in D. hastatus, with 2n = 50 = 6M+8SM+8ST+28A. We obtained three different clades of D. hastatus in our phylogeny, one of them composed only by specimens of cytotype D. By using molecular clock dating, we observed that the radiation of Deuterodon from southeastern Brazil seemed to be associated with neotectonic events that occurred during the Miocene-Pliocene and Pliocene-Pleistocene transitions, marked by the capture of headwater streams and marine transgressions. The results obtained reinforce the idea that D. hastatus is a species complex, and at least three evolutionary significant units were identified in this group.

Abstract Nephron-sparing surgery (partial nephrectomy) has provided multiple benefits, mainly in patients with small kidney lesions or concomitant diseases that affect overall kidney function in long term, also in patients with a single functional kidney, either congenital or by surgery, end-stage renal disease, bilateral renal tumors or with chromosomal diseases that affects the renal function. The case of a 52-years-old male patient is presented with a 10-cm right kidney tumor in the interpolar region, with not functional left kidney exclusion due to an obstructive process by congenital ureteropyelic stenosis. Right nephron-sparing nephrectomy was performed despite the location and size of the tumor, obtaining excellent oncological and functional results. Follow-up at twelve months of postoperative evolution showed no data of tumor activity, presenting renal function with creatinine of 1.6 mg/dl, with satisfactory evolution. Conclusions: Partial nephrectomy is the standard management for small-volume renal tumors located in the renal cortex and polar areas, or not functional contralateral kidney; but there is the dilemma, when patients appear with impaired renal function or tumors located near the renal hilum by > 5 cm of diameter, the risk of performs this procedure must be taken, the laparoscopic approach is an excellent option. with great results, and minor bleeding than open surgery.

Resumen La nefrectomia parcial ha proporcionado múltiples beneficios principalmente en pacientes con lesiones renales de pequeño tamaño o con enfermedades que puedan afectar el funcionamiento renal a largo plazo, también en pacientes con riñón único funcional, ya sea congènita o por cirugía, enfermedad renal terminal, tumores renales bilaterales o con enfermedades cromosómicas que afecten la función renal.Se presenta el caso de un paciente de 52 años con un tumor de riñón derecho de 10 cm de diámetro en región interpolar, con riñón izquierdo sin función, por proceso obstructivo de estenosis ureteropielica congènita. Se realizó nefrectomia parcial derecha a pesar de la localización y tamaño del tumor renal, obteniendo excelentes resultados oncológicos y funcionales. Con un seguimiento a doce meses de evaluación post-operatoria sin datos de actividad tumoral, presentando una función renal con creatinina 1.6 mg/dl, con evolución satisfactoria. Conclusiones: La nefrectomia parcial es el manejo ideal para tumores renales pequeños que están localizados en la corteza renal y en los extremos polares del riñón o con un riñón contralateral sin función; pero hay el dilema cuando se presentan en pacientes con función renal baja o tumores localizados cerca del hilio renal de más de 5 cm de diámetro, se debe tomar los riesgo de intentar realizar este procedimiento, el abordaje por via laparoscópica es excelente opción con excelentes resultados, con menor riesgo de complicaciones, y menor sangrado que cirugía abierta.

Abstract Contrary to predictions from classical hybrid sterility models of chromosomal speciation, some organisms display high rates of karyotype variation. Ctenomys are the current mammals with the greatest interspecific and intraspecific chromosomal variation. A large number of species have been studied cytogenetically. The diploid numbers of chromosomes range from 2n = 10 to 2n = 70. Here, we analyzed karyotype evolution in Ctenomys using comparative phylogenetic methods. We found a strong phylogenetic signal with chromosome number. This refutes the chromosomal megaevolution model, which proposes the independent accumulation of multiple chromosomal rearrangements in each closely related species. We found that Brownian motion (BM) described the observed characteristic changes more thoroughly than the Ornstein-Uhlenbeck and Early-Burst models. This suggests that the evolution of chromosome numbers occurs by a random walk along phylogenetic clades. However, our data indicate that the BM model alone does not fully characterize the chromosomal evolution of Ctenomys. speciation variation cytogenetically n 1 70 Here methods (BM OrnsteinUhlenbeck Ornstein Uhlenbeck EarlyBurst Early Burst clades However 7

RESUMEN Los estudios de citogenética en Primates Neotropicales (Primates: Platyrrhini) han demostrado que estos mamíferos comprenden un grupo heterogéneo a nivel cromosómico. La notable variedad de cariotipos descriptos provee evidencia significativa sobre el posible papel de los reordenamientos cromosómicos en su evolución. En el Grupo de Investigación en Biología Evolutiva (GIBE), la línea de investigación sobre el proceso de divergencia evolutiva en Platyrrhini considerando distintos aspectos de la organización del genoma se ha establecido y desarrollado de manera ininterrumpida desde hace más de 30 años. Entre los avances realizados en los últimos años se encuentra la cuantificación del tamaño del genoma en seis especies de monos caí (Cebus sp.) y dos especies de monos aulladores (Alouatta sp.) y la descripción de la composición de pares de bases en las regiones de heterocromatina constitutiva en los géneros Cebus y Ateles. Se concretaron las primeras descripciones del cariotipo y comportamiento meiótico en profase I temprana de dos especies de monos aulladores, Alouatta caraya y A. guariba clamitans. En esta última especie se identificó el primer sistema sexual de tipo pentavalente X1X2X3Y1Y2 en una especie de primate. Se caracterizó la organización de la eucromatina en términos del contenido y distribución de bases nucleotídicas AT y GC en tres especies de aulladores y en dos especies de monos caí. Estas investigaciones, entre otras, permitieron contribuir de forma original al conocimiento sobre la especiación en distintos niveles, así como sobre la arquitectura y dinámica del genoma de estos primates.

ABSTRACT Cytogenetics studies in Neotropical Primates (Primates: Platyrrhini) have shown that these mammals comprise a heterogeneous group at the chromosomal level. The remarkable variety of karyotypes described provides significant evidence on the possible role of chromosomal rearrangements in their evolution. In the Grupo de Investigación en Biología Evolutiva (GIBE), the line of research on the evolutionary divergence process in Platyrrhini considering different aspects of the organization of the genome has been established and developed uninterruptedly for more than 30 years. Among the advances made in recent years is the quantification of the genome size in six species of caí monkeys (Cebus sp.) and two species of howler monkeys (Alouatta sp.) and the description of the composition of base pairs in the constitutive heterochromatin regions in the genera Cebus and Ateles. The first descriptions were made of the karyotype and meiotic behavior in early prophase I of two species of howler monkeys, Alouatta caraya and A. guariba clamitans. In this last species, the first pentavalent-type sexual system X1X2X3Y1Y2 was identified in a primate species. The organization of euchromatin was characterized in terms of the content and distribution of AT and GC nucleotide bases in three species of howlers and in two species of caí monkeys. These, among other investigations, allowed contributing in an original way to the knowledge about speciation at different levels, as well as about the architecture and dynamics of the genome of these primates.

RESUMEN La subfamilia Bambusoideae comprende tres tribus monofiléticas, Arundinarieae, Bambuseae y Olyreae. Aquí reportamos el número gamético y el comportamiento meiótico de los cromosomas de dos especies pertenecientes a la tribu Olyreae de bambúes herbáceos, Olyra latifolia y Olyra humilis. Las introducciones se recolectaron en la provincia de Misiones, en el noreste argentino. Reportamos un nuevo número gamético para O. humilis, n=18, y confirmamos n=11 para O. latifolia. Los números cromosómicos básicos y gaméticos son importantes para comprender la evolución de la familia Poaceae, especialmente para delimitar sus clados y las relaciones existentes entre ellos, por lo que es necesario continuar produciendo este tipo de datos.

ABSTRACT The subfamily Bambusoideae comprises three monophyletic tribes, Arundinarieae, Bambuseae and Olyreae. Here we report the gametic number and the chromosomal meiotic behavior of two species belonging to the herbaceous tribe Olyreae, Olyra latifolia and Olyrahumilis. Accessions were collected in Misiones, at Northeastern Argentina. We report a new gametic number for O. humilis, n=18, and we confirmed n=11 for O. latifolia. Chromosomal features, like the basic and gametic chromosome number, are important in understanding the evolution of the Poaceae family, especially in delimiting clades and elucidate inter andintra-clades relationships, and therefore it is necessary to continue producing this type of data.