Objetivos: Analisar por meio da técnica de sequenciamento direto a presença de alterações moleculares nos genes SHH, SIX3, ZIC2 e TGIF1 em indivíduos com diagnóstico clínico de HPE. Analisar por meio da técnica de CGH-array a presença de alterações moleculares em indivíduos com diagnóstico clínico de HPE previamente submetidos à análise por sequenciamento direto. Local: Laboratório de Genética e Citogenética Humana HRAC/USP, Bauru-SP. Casuística e metodologia: Foram selecionados 50 indivíduos, de ambos os sexos com idades entre 03 meses a 50 anos com diagnóstico clínico para HPE. Todos foram analisados por meio da técnica de sequenciamento direto para os genes SHH e TGIF1 completamente e para os genes ZIC2 e SIX3 parcialmente. Dentre os indivíduos que não apresentaram alterações na técnica de sequenciamento oito indivíduos com fenótipo mais grave foram selecionados para a análise por CGH-array. Resultados e discussão: Foram analisados 50 indivíduos por meio da técnica de sequenciamento direto dos gene SHH e TGIF1, foram encontradas duas variantes patogênicas na análise do gene SHH, no caso 1 a variante p.24G>P foi identificada, e no caso 2 foi identificada a variante c.1031del C. No gene TGIF1 foram encontrados cinco polimorfismos já descritos na literatura. Foi identificada uma nova variante silenciosa no éxon 1 do gene ZIC2 p.Q46Q (c. 431 G>A) e um polimorfismo já descrito na literatura em dois indivíduos no gene SIX3. A análise por CGH-array revelou a presença de uma microdeleção no caso 37, de 1,5Mb no cromossomo 17p12 entre as posições genômicas 14,052,279-15,102,307. A mesma deleção foi encontrada na mãe, sendo que esta região nunca foi associada a HPE. Conclusão: A técnica de sequenciamento direto é uma ferramenta muito importante no diagnóstico molecular da HPE, a padronização do sequenciamento direto para os genes ZIC2 e SIX3 poderá auxiliar em diagnósticos mais precisos em estudos futuros dentro do HRAC/USP. O emprego de novas técnicas como CGH-array pode indicar novas relações entre regiões cromossômicas e os múltiplos fatores envolvidos na formação da HPE. / Objective: Analyze through direct sequencing technique the presence of molecular changes on the genes SHH, SIX3, ZIC2 and TGIF1 on individuals with clinical diagnosis of HPE. Analyze through array-CGH technique the presence of molecular changes on individuals with clinical diagnosis of HPE previously submitted to the direct sequencing analyzes. Local: Genetics and Human Cytogenetics Laboratory, HRAC/USP, Bauru-SP. Methods: Were selected 50 individuals from both genders with ages between 03 months and 50 years clinically diagnosed with HPE. Everyone was analyzed through the direct sequencing technique for the genes SHH and TGIF1 completely and for the genes ZIC2 and SIX3 partially. From those individuals which did not have shown changes on the direct sequencing technique, eight individuals with more severe phenotype were selected to the analysis through array-CGH. Results an Discussion: Were analyzed 50 individuals through the technique of direct sequencing of the genes SHH and TGIF1, were found two pathogenic variants in the analysis of SHH gene, in the case 1, the variant p.G24P was identified, and in the case 2 was identified the variant c.1031delC. On the TGIF1 gene were found five polymorphisms already described on the literature. Was identified a new silent variant on the exon 1 of the ZIC2 gene p. Q46Q(c.431G>A) and a polymorphism already described in the literature in two individuals on the gene SIX3. The analysis through array-CGH revealed the presence of one microdeletion in the case 37, of 1,5 Mb on the region 17p12 between the genomic positions 14,052,279-15,102,307. The same deletion was detected in the mother, though this region was never associated to the HPE. Conclusion: The direct sequencing technique is a very important tool for the molecular diagnosis of the HPE, and the direct sequencing standardization for the genes ZIC2 and SIX3 might help in more precise diagnostics on HRAC/USP future studies. The employ of new techniques such as array-CGH may indicate new relations between chromosomal regions and the multiple hit involved in the development of HPE.

Objetivos: Analisar por meio da técnica de sequenciamento direto a presença de alterações moleculares nos genes SHH, SIX3, ZIC2 e TGIF1 em indivíduos com diagnóstico clínico de HPE. Analisar por meio da técnica de CGH-array a presença de alterações moleculares em indivíduos com diagnóstico clínico de HPE previamente submetidos à análise por sequenciamento direto. Local: Laboratório de Genética e Citogenética Humana HRAC/USP, Bauru-SP. Casuística e metodologia: Foram selecionados 50 indivíduos, de ambos os sexos com idades entre 03 meses a 50 anos com diagnóstico clínico para HPE. Todos foram analisados por meio da técnica de sequenciamento direto para os genes SHH e TGIF1 completamente e para os genes ZIC2 e SIX3 parcialmente. Dentre os indivíduos que não apresentaram alterações na técnica de sequenciamento oito indivíduos com fenótipo mais grave foram selecionados para a análise por CGH-array. Resultados e discussão: Foram analisados 50 indivíduos por meio da técnica de sequenciamento direto dos gene SHH e TGIF1, foram encontradas duas variantes patogênicas na análise do gene SHH, no caso 1 a variante p.24G>P foi identificada, e no caso 2 foi identificada a variante c.1031del C. No gene TGIF1 foram encontrados cinco polimorfismos já descritos na literatura. Foi identificada uma nova variante silenciosa no éxon 1 do gene ZIC2 p.Q46Q (c. 431 G>A) e um polimorfismo já descrito na literatura em dois indivíduos no gene SIX3. A análise por CGH-array revelou a presença de uma microdeleção no caso 37, de 1,5Mb no cromossomo 17p12 entre as posições genômicas 14,052,279-15,102,307. A mesma deleção foi encontrada na mãe, sendo que esta região nunca foi associada a HPE. Conclusão: A técnica de sequenciamento direto é uma ferramenta muito importante no diagnóstico molecular da HPE, a padronização do sequenciamento direto para os genes ZIC2 e SIX3 poderá auxiliar em diagnósticos mais precisos em estudos futuros dentro do HRAC/USP. O emprego de novas técnicas como CGH-array pode indicar novas relações entre regiões cromossômicas e os múltiplos fatores envolvidos na formação da HPE. / Objective: Analyze through direct sequencing technique the presence of molecular changes on the genes SHH, SIX3, ZIC2 and TGIF1 on individuals with clinical diagnosis of HPE. Analyze through array-CGH technique the presence of molecular changes on individuals with clinical diagnosis of HPE previously submitted to the direct sequencing analyzes. Local: Genetics and Human Cytogenetics Laboratory, HRAC/USP, Bauru-SP. Methods: Were selected 50 individuals from both genders with ages between 03 months and 50 years clinically diagnosed with HPE. Everyone was analyzed through the direct sequencing technique for the genes SHH and TGIF1 completely and for the genes ZIC2 and SIX3 partially. From those individuals which did not have shown changes on the direct sequencing technique, eight individuals with more severe phenotype were selected to the analysis through array-CGH. Results an Discussion: Were analyzed 50 individuals through the technique of direct sequencing of the genes SHH and TGIF1, were found two pathogenic variants in the analysis of SHH gene, in the case 1, the variant p.G24P was identified, and in the case 2 was identified the variant c.1031delC. On the TGIF1 gene were found five polymorphisms already described on the literature. Was identified a new silent variant on the exon 1 of the ZIC2 gene p. Q46Q(c.431G>A) and a polymorphism already described in the literature in two individuals on the gene SIX3. The analysis through array-CGH revealed the presence of one microdeletion in the case 37, of 1,5 Mb on the region 17p12 between the genomic positions 14,052,279-15,102,307. The same deletion was detected in the mother, though this region was never associated to the HPE. Conclusion: The direct sequencing technique is a very important tool for the molecular diagnosis of the HPE, and the direct sequencing standardization for the genes ZIC2 and SIX3 might help in more precise diagnostics on HRAC/USP future studies. The employ of new techniques such as array-CGH may indicate new relations between chromosomal regions and the multiple hit involved in the development of HPE.

Ranunculus trichophyllus agg. (thread-leaved water crowfoot) represents a taxonomically challenging group of aquatic plants in which the presence of several significantly different genotypes and the genome size variation have been recently revealed. The results of previous studies suggest that cryptic taxa occur in this group, being so far overlooked due to considerable morphological reduction and extensivephenotypic plasticity. In this thesis, the variation and genetic relationships of four morphologically similar homophyllous water-crowfoot species was critically assessed in the area of Central Europe, using a combination of modern biosystematic methods (flow cytometry, direct DNA sequencing, morphometric analyses), specially focusing on the complex of R. trichophyllus.. The genome size analysis via flow cytometry was confirmed as a suitable method for determining the studied species; further, several hybrid combinations were revealed using this approach. However, recent interspecific hybridization is rather infrequent in the interest group. The results of DNA analyses indicate an importance of hybridization events in the evolution of sect. Batrachium: all the polyploid taxa studied are probably of allopolyploid origin. Two cryptic taxa within the traditionally recognized species R. trichophyllus have...

Aboveground and belowground ectomycorrhizal (ECM) communities associated with different age classes of the exotic plantation species Pinus radiata were investigated over the course of two years in the North Island of New Zealand. ECM species were identified with a combined approach of morphological and molecular (restriction fragment length polymorphism (RFLP) and DNA sequencing) analysis. ECM species richness and diversity of a nursery in Rotorua, and stands of different ages (1, 2, 8, 15 and 26 yrs of age at time of final assessment) in Kaingaroa Forest, were assessed above- and belowground; furthermore, the correlation between the above- and belowground ECM communities was assessed. It was found that the overall and stand specific species richness and diversity of ECM fungi associated with the exotic host tree in New Zealand were low compared to similar forests in the Northern Hemisphere but similar to other exotic plantations in the Southern Hemisphere. Over the course of this study, 18 ECM species were observed aboveground and 19 ECM species belowground. With the aid of molecular analysis the identities of Laccaria proxima and Inocybe sindonia were clarified. In the aboveground study, five species were found associated with P. radiata that were previously not reported with this host in New Zealand (Inocybe sindonia, Lactarius rufus, Lycoperdon gunii, Rhizopogon pseudoroseolus and Wilcoxina mikolae). Belowground, the species Psudotomentella sp., P. tristis, R. luteorubescens, Tomentella sp., Wilcoxina mikolae were found as new associates of P. radiata in New Zealand, additionally nine ECM types were found that could not be identified with molecular analysis. There was little correlation between the species fruiting and the species colonising root tips. Only seven species were found in common between the above- and belowground communities, furthermore the dominant species aboveground were not observed in the belowground ECM communities. The influence of host age on the above- and belowground ECM communities of different age classes of P. radiata plantations was investigated. The aboveground species richness increased from the nursery to the oldest age group investigated (26 yrs), while diversity increased to the 15 yr old age group and decreased slightly to the oldest stand. A clear sequence of ECM species changes was observed to be related to stand age with a growing complexity over the chronosequence. The belowground ECM communities showed a different picture and richness and diversity initially decreased from the nursery to the outplanting but increased thereafter. Belowground no change in ECM composition that was directly related to the age of the host was observed, but two distinct groups of ECM species were found – a 'young' and a 'plantation forest' group, with the respective discriminating species being Rhizopogon rubescens and Type unknown Basidiomycete/Amanita muscaria. Another aspect of the study was the fate of the nursery ECM species in the outplanting and the arrival of non-nursery species. The ECM communities of seedlings in the nursery were investigated in 2006 and these seedlings were followed up over eight assessments in the field for one year, furthermore data from the 1-, 2 and 8 yr old plantation stands was analysed. It was found that the nursery species do survive the first year of outplanting and are dominant in the first year. The first non-nursery species occurred six months after outplanting but was only in minor abundance. Nursery ECM were dominant for two years after the seedlings were planted, and were completely replaced after seven years. Rhizopogon rubescens was found to be the most persistent and dominant species in the outplanting, facilitating the successful establishment of the seedlings in the plantation forest.

The aetiological diagnosis of recessive non-syndromic hearing loss poses a challenge owing to marked heterogeneity and the lack of identifying clinical features. The finding that up to 50% of recessive non-syndromal genetic hearing loss among Caucasians was due to mutations in GJB2, the gene encoding Connexin 26 (Cx26) was a breakthrough, whose value as a diagnostic tool has been limited by the significant variation in the prevalence of deafness genes and loci among population groups. The significant association of the GJB6-D13S1830 deletion among individuals with one mutant GJB2 allele highlighted the need to explore population specific genetic mutations for NSHL. Although data from Sub-Saharan Africa is limited, reported studies found a high prevalence of R143W GJB2 mutation among Ghanaian, the 35delG mutation in 5 out of 139 Sudanese and a low prevalence of GJB2 variations among 385 Kenyan deaf children. The mutation spectrum of Waardenburg Syndrome (WS) in Africans has not been documented. During a visit to a School for the Deaf in the Limpopo Province of South Africa in 1997, it was noted that a high number of students came from Nzhelele sub-district. All had childhood onset hearing loss with no associated anomalies or disorders. The question arose as to whether there was a high-risk area for deafness in the Limpopo Province and what the aetiology of this hearing loss was.The main aim of this study was to investigate the role of GJB2, the GJB6-D13S1830 deletion, and the four common mitochondrial mutations, A1555G, A3243G, A7511C and A7445G, in the African hearing-impaired population of Limpopo province in South Africa, and to identify the mutation spectrum of the deafness genes found. The type and degree of hearing loss in this hearing impaired population would also be assessed. Secondly, this study sought to identify the mutations in a sibling pair with 2 clinical WS and to use the findings in a future study to establish the mutation spectrum of WS in the African population of the Limpopo province and of South Africa in general. The study was designed as a two phase study, in which phase 1 was used for hypothesis formulation and phase 2 was for hypothesis testing. While phase 1 was a descriptive retrospective case study, phase 2 was a combination of sample survey and prospective descriptive case study. In phase 1, demographic data of 361 students in two schools of the deaf in the Limpopo province was analyzed for evidence of areas of high risk populations for deafness in the province. In phase 2, a group of 182 individuals with genetic non-syndromic hearing loss (NSHL) and two siblings with clinical WS from two schools for the Deaf in the Limpopo Province of South Africa were investigated. A thorough clinical examination, audiological evaluation and urinalysis were done. Mutational screening was carried out in all 184 subjects using genomic DNA using single-strand conformation polymorphism (SSCP), multiplex polymerase chain reaction (PCR), and direct sequencing for GJB2, and Restriction Fragment-Length Polymorphism (PCR–RFLP) analysis for GJB6, and SSCP, hetero-duplex analysis, and direct sequencing of the first 8 exons of PAX3 and all of MITF for Waarenburg syndrome. Data analysis was by geographical mapping, frequency tables, tests of association with calculation of odds ratios, and binary logistic regression analysis using STATA and GIS mapping systems. The results indicate that there seem to be areas of genuine populations at risk for hearing loss in the Limpopo province of South Africa, namely Mutale and parts of Makhado and Thulamela municipalities. In Thulamela (NP343) wards 11-15, 26-30 and 31-35, and in Mutale (NP 344) wards 6-10, together accounted for 67 (18%) of participants in phase 1, and 33 (18%) of the participants in phase 2 of the study. Mutale municipality in the Vhembe 3 district gave with a projected prevalence of at least 13.14 deaf children per 100,000 African population attending the local school for the deaf. The observed hearing loss is a genetic, non-syndromic form, which is mainly severe and severe to profound, although without any clear defining configuration or shape. It is a stable, non-progressive and prelingual form of hearing loss, implying that this may be a recessive form of deafness. No identifiable environmental confounding factors or associations were identified. The deafness is not linked the common known auditory gene mutations in GJB2, the GJB6-D13S1830 deletion, or the common mitochondrial mutations A1555G, A3243G, A7511C and A7445G. Severe and profound levels of hearing loss were found in 22.8% and 75% of the cohort respectively, with the majority exhibiting flat (70.1%) or sloping (23.4%) audiograms that were commonly symmetrical (81.5%). However, as indicated, there was no clear pattern in the audiological findings overall. None of the 184 hearing impaired individuals exhibited any of the reported disease causing mutations of GJB2, including 35delG. There was, however, a high prevalence of two variants, the C>T variant at position g.3318-15 and the C>T variant at position g.3318-34, occurring in 21.4% and 46.2% of the deaf cohort respectively. The same variants were found to occur in 35% and 42.6% of a normal hearing control group (n = 63) respectively, indicating that these variations are polymorphisms. In three subjects (1.63% of the cohort), a T>A homozygous variation at position g.3318-6 was detected. Its significance in the causation of NSSNHL is yet to be determined. The GJB6-D13S1830 deletion was not detected in any of the participants. None of the four mitochondrial mutations screened for were found. 4 These results indicate that GJB2 is not a significant deafness gene in the African population of the Limpopo Province of South Africa and that significant genes for non-syndromic recessive hearing loss in this population are yet to be found. The geographical clustering of deafness found in this study, combined with the lack of identifiable common associated clinical features among the subjects of this study (excluding the WS sibling pair), suggests that these subjects have a genetic recessive non-syndromal type of hearing loss. In the context of historical and cultural evidence of consanguinity in this population, a founder effect cannot be ruled out. A rare mutation, R223X, previously identified only once out of 470 WS patients, was identified in the PAX3 gene among the WS sibling pair. A novel silent change GGG>GGT at amino acid 293, was also identified. These identical findings document, for the first time, a molecular defect in WS in an African sibling pair, and confirm WS Type I in this family, which could be found in other WS type I South Africans in the Limpopo Province of South Africa. The current study demonstrated that parents of genetically hearing impaired children in these areas are able to detect hearing loss at an early age, with over 60% suspecting their children’s hearing loss below 6 months of age. A child-centered management model encompassing all the areas relevant to childhood deafness/hearing impairment, which takes into consideration the prevailing logistical and financial constraints of the available healthcare system, is proposed. The implementation of this model requires a paradigm shift from the current fragmented model of service delivery to a cohesive patient-centered approach, based on concrete data from appropriate community based research, in which all the relevant parties communicate and share resources. 5 It would achieve the goals of early detection and intervention, as well as inclusive education for all. The relevant health and education policies are already in place and the posts funded. Equitable implementation of these policies would require appropriate community based research, as well as improved communication and consultation between the various stakeholders to ensure an efficient and affordable quality healthcare service for all hearing impaired South Africans.