Auto- and allopolyploidy in Centaurea sect. Acrocentron s.l. (Asteraceae, Cardueae): karyotype and chromosome banding pattern analyses

Dysploidy and polyploidy are well documented in the large genus Centaurea, especially in sect. Acrocentron and in a small group of species from the Iberian Peninsula described as sect. Chamaecyanus, closely related to Acrocentron. We have explored two interesting cases of polyploid series in both sections: the polyploid series of Centaurea toletana in sect. Chamaecyanus and the series of C. ornata group in sect. Acrocentron. We have carried out a karyological study using both classic karyotype analyses and chromosome banding with fluorochromes.

Analysis of meiotic recombination in 22q11.2, a region that frequently undergoes deletions and duplications

Background: The 22q11.2 deletion syndrome is the most frequent genomic disorder with an estimated frequency of 1/4000 live births. The majority of patients (90%) have the same deletion of 3 Mb (Typically Deleted Region, TDR) that results from aberrant recombination at meiosis between region specific low-copy repeats (LCRs). Methods: As a first step towards the characterization of recombination rates and breakpoints within the 22q11.2 region we have constructed a high resolution recombination breakpoint map based on pedigree analysis and a population-based historical recombination map based on LD analysis. Results: Our pedigree map allows the location of recombination breakpoints with a high resolution (potential recombination hotspots), and this approach has led to the identification of 5 breakpoint segments of 50 kb or less (8.6 kb the smallest), that coincide with historical hotspots. It has been suggested that aberrant recombination leading to deletion (and duplication) is caused by low rates of Allelic Homologous Recombination (AHR) within the affected region. However, recombination rate estimates for 22q11.2 region show that neither average recombination rates in the 22q11.2 region or within LCR22-2 (the LCR implicated in most deletions and duplications), are significantly below chromosome 22 averages. Furthermore, LCR22-2, the repeat most frequently implicated in rearrangements, is also the LCR22 with the highest levels of AHR. In addition, we find recombination events in the 22q11.2 region to cluster within families. Within this context, the same chromosome recombines twice in one family; first by AHR and in the next generation by NAHR resulting in an individual affected with the del22q11.2 syndrome. Conclusion: We show in the context of a first high resolution pedigree map of the 22q11.2 region that NAHR within LCR22 leading to duplications and deletions cannot be explained exclusively under a hypothesis of low AHR rates. In addition, we find that AHR recombination events cluster within families. If normal and aberrant recombination are mechanistically related, the fact that LCR22s undergo frequent AHR and that we find familial differences in recombination rates within the 22q11.2 region would have obvious health-related implications.

Hearing loss in Adult Women with Turner Syndrome

L'objectiu d'aquest estudi és definir els patrons d’hipoacúsia en dones amb Síndrome de Turner i els possibles factors que poden afavorir el desenvolupament d’hipoacúsia neurosensorial en dones adultes amb Síndrome de Turner. Es va trobar que més de la meitat de les dones amb Sindrome de Turner presenten hipoacúsia a l’audiometria, confirmat pels potencials evocats auditius de tronc; la hipoacúsia neurosensorial és el tipus de pèrdua d'audició més freqüent entre dones de mitjana edat amb síndrome de Turner i l'edat, el cariotip i la història prèvia d'otitis mitja recurrent són possibles factors de risc per l’aparició d’hipoacúsia en aquestes pacients.

Oral findings in Midline Syndrome: a case report and literature review

We describe a female patient with a midline syndrome. The patient presents agenesis of the corpus callosum, encephalocele, iris coloboma, hypertelorism, submucosal cleft palate and dental anomalies. Despite being very characteristic, her phenotypical traits do not coincide exactly with those reported to date in the literature. The karyotype and the molecular cytogenetic study do not show mutations. We identify the presence of dental anomalies in the mother and other family members, not being identified MSX1 and PAX9 mutations that could the related with their etiology. Despite the fact that dental agenesis has been related to a large number of other malformation syndromes and congenital conditions, dental anomalies have only rarely been mentioned when reporting midline syndromes. These dental phenotypical traits, present in the patient and her family, could be considered part of the midline syndrome in carriers as well as in the patients.

Plantas hospedantes de Rhopalosiphum maidis (Fitch) (Homoptera: Aphididae) y su papel en el ciclo biológico del pulgón en Cataluña

Se evaluó el papel de las distintas plantas hospedantes de Rhopalosiphum maidis (Fitch) en el ciclo biológico anual de los dos cariotipos más comunes en Cataluña (2n = 8 y 2n = 10 cromosomas) mediante el seguimiento de poblaciones de pulgones en cereales de invierno y verano y en gramíneas espontáneas. Asimismo se registró la densidad de R. maidis en parcelas comerciales de maíz y se determinó el periodo de colonización mediante la instalación de una trampa de succión. Las gramíneas espontáneas juegan un papel fundamental en el ciclo biológico anual de ambos cariotipos. Los pulgones de cariotipo 2n = 10 pueden vivir sobre cebada durante el otoño, invierno y primavera, y sobre gramíneas adventicias, como Setaria sp. y Echinochloa crus-galli ((L.) P. Beauv.), en verano e inicios de otoño; la superposición del ciclo de estas gramíneas permite a los pulgones con este cariotipo cerrar su ciclo anual en ellas. En el caso de los pulgones de cariotipo 2n = 8, el sorgo es el principal hospedante de verano; la cañota constituye un hospedante básico en primavera y otoño, pudiendo actuar como hospedante en inviernos extremadamente cálidos. El periodo primaveral de colonización del maíz por R. maidis se produjo principalmente en mayo y duró hasta mediados de junio. El número de alados capturados en la trampa de succión, así como el de individuos hallados sobre plantas, fue muy bajo tanto en mayo como en junio. Los resultados obtenidos sugieren que el maíz no juega un papel relevante en el ciclo de R. maidis. Se analizan algunas de las posibles causas de este fenómeno.

Ensayo de preferencia de individuos alados de Rhopalosiphum maidis (Fitch) (Homoptera: Aphididae) sobre siete gramíneas cultivadas

Se evaluó en laboratorio la preferencia de dos poblaciones leridanas de Rhopalosiphum maidis (Fitch) en la colonización de siete gramíneas cultivadas. Una de las poblaciones fue recogida sobre cañota (Sorghum halepense C. (L.) Pers.) y su cariotipo era 2n = 8. Los individuos de la otra población presentaban un cariotipo 2n = 10 y procedían de cebada. Las gramíneas testadas fueron: sorgo, maíz, trigo, trigo duro, cebada, triticale y avena. Los individuos alados de ambas poblaciones colonizaron los siete cereales aunque de distinta manera. El sorgo fue preferentemente colonizado por los pulgones con cariotipo 2n = 8 y el número de ninfas producidas en 48 horas fue mayor que en el resto de las gramíneas testadas. Los pulgones con cariotipo 2n = 10 mostraron preferencia por la cebada. Los alados de ambas poblaciones fueron incapaces de reproducirse sobre las plantas de maíz.

Chromosomal polymorphism of D. subobscura: no differences between wild males and sons of wild females

When analyzing the chromosomal polymorphism of D. subobscura natural populations it is assumed that the information provided by wild males and sons of wild females is equivalent. Thus, using both in the analysis it is possible to increase the sample size. However, it is important to verify whether there are significant differences between both groups or not. The aim of this research has been to statistically compare the results of chromosomal polymorphism of both groups. We have used data from Avala Mountain (Serbia) where D. subobscura flies were collected from the 30th May to the 5th June 2011. Avala is located 18 km south of Belgrade and the trapping place is a forest with polydominant communities of Fagetum submontanum Table 1. Number and percentage of adult flies collected in Font Groga (Barcelona, Spain) on 9th October 2013. Males and sons of wild females were crossed with virgin females of the Küsnacht strain. Third instar larvae from F1 were dissected to obtain the salivary glands and the polytene chromosomes were stained and squashed in aceto-orcein solution. No significant differences were observed for any chromosome of the karyotype: A (p-value = 0.485), J (p-value = 0.230), U (p-value =0.572), E (p-value = 0.536), and O (p-value = 0.338). Thus, it seems that the two groups can be grouped together to obtain the chromosomal polymorphism of the population.