Essays on Ethnic Diversity and Development

This dissertation consists of three papers. The first paper "Ethnicity, Migration and Conflict: Evidence from Contemporary South Africa” exploits some of the institutional changes intervened in South Africa during the end of apartheid to investigate the relationship between ethnic diversity and conflict. I find within-ethnic polarization to be significantly related to the intensity of armed confrontations among black-dominated groups. My investigation thus gives strong and robust empirical support to the theoretical arguments which identify ethnic diversity as one of the determinants of civil conflict. The second chapter, "Pre-Colonial Centralization, Colonial Activities and Development in Latin America", investigates the hypothesis that pre-colonial ethnic institutions shaped contemporary regional development in Latin America. I document a strong and positive relationship between pre-colonial centralization and regional development. Results are in line with the view that highly centralized pre-colonial societies acted as a persistent force of agglomeration of economic activities and a strong predictor of colonial state capacity. The results provide a first evidence of the existence of a link between pre-colonial centralization, colonial institutional arrangements and contemporary economic development. The third paper "Bite and Divide: Malaria and Ethnic Diversity” investigates the role of malaria as a fundamental determinant of modern ethnic diversity. This paper explores the hypothesis, that a large exposure to malaria has fostered differential interactions that reduced contacts between groups and increased interactions within them Results document that malaria increases the number of ethnic groups at all levels of spatial disaggregation and time periods (exploiting historical and current ethnic diversity). Regressions' results show that endogamous marriages are more frequent in areas with higher geographic suitability to malaria. The results are in line with the view that malaria increases intra-ethnic interactions while decreasing inter-ethnic ones.

Diversity and local democracy. The case of Republic of Macedonia - implications of ethnic diversity on municipal decision making and organizational performance

This research seeks to review the level of knowledge achieved in interpreting the relationship between the ethnic diversity at the workplace in the public sector and the organizational performance; as well as seeks to contribute in understanding the implications of this relationship. The study commenced with investigating the academic research in the relevant area addressing the following research questions: (a) How are diversity management and organizational performance conceptualized? (b) What are the existing findings of research concerning diversity at the workplace in the public organizations and organizational performance? (c) What factors intervene the relationship between the diversity and organizational performance? Based on the findings from the review of the academic research, this study seeks to contribute in understanding the ethnic diversity – performance relationship and its mplications at the local level in the Macedonian context. The reform process in Macedonia as a multicultural society, where for many years, inter-ethnic relations have been one of the most sensitive political issues, affecting both the stability of the country and the progress, focused mainly on the implementation of the decentralization and inclusion of ethnic minorities in the decision making process. With the implementation of the Ohrid Framework Agreement workforce at the units of local self-government in Republic of Macedonia is becoming more balanced with respect to ethnic minorities, with more workforce participation than ever by Albanians, Turks, Roma and other minorities. As public organizations at local level become more diverse along ethnic lines, it makes sense to pay more attention to how different ethnic groups interact with one another at work. Thus it gives additional importance on the research question addressed in the study and gives significance of the research in a broader scope.

Comparing genetic and linguistic diversity in African populations with a focus on the Khoisan of southern Africa

The interaction between disciplines in the study of human population history is of primary importance, profiting from the biological and cultural characteristics of humankind. In fact, data from genetics, linguistics, archaeology and cultural anthropology can be combined to allow for a broader research perspective. This multidisciplinary approach is here applied to the study of the prehistory of sub-Saharan African populations: in this continent, where Homo sapiens originally started his evolution and diversification, the understanding of the patterns of human variation has a crucial relevance. For this dissertation, molecular data is interpreted and complemented with a major contribution from linguistics: linguistic data are compared to the genetic data and the research questions are contextualized within a linguistic perspective. In the four articles proposed, we analyze Y chromosome SNPs and STRs profiles and full mtDNA genomes on a representative number of samples to investigate key questions of African human variability. Some of these questions address i) the amount of genetic variation on a continental scale and the effects of the widespread migration of Bantu speakers, ii) the extent of ancient population structure, which has been lost in present day populations, iii) the colonization of the southern edge of the continent together with the degree of population contact/replacement, and iv) the prehistory of the diverse Khoisan ethnolinguistic groups, who were traditionally understudied despite representing one of the most ancient divergences of modern human phylogeny. Our results uncover a deep level of genetic structure within the continent and a multilayered pattern of contact between populations. These case studies represent a valuable contribution to the debate on our prehistory and open up further research threads.

Phylogeny and genetic diversity of Italian species of hares (genus Lepus)

In this study we have analysed the genetic variability in ca. 700 samples belonging to six species of genus Lepus using maternal and biparental molecular markers (mitochondrial DNA, microsatellites, Single Nucleotide Polimorphisms). We aimed to reconstruct the phylogenetic relationships of species of hares living in Europe, and assess the occurrence of hybridization between the European hare Lepus europaeus and the Italian hare Lepus corsicanus. Results showed a deep genetic differentiation and absence of hybridization between L. corsicanus and L. europaeus, confirming that they are distinct and distantly related biological species. In contrast, we showed small genetic distances and a close phylogenetic relationship between the Italian hare and Cantabrian hare L. castroviejoi, which suggest a deeper evaluation of their taxonomic status. Populations of L. corsicanus are geographically differentiated. In particular, the peninsular and Sicilian populations of Italian hares are sharply genetically distinct, which calls for avoiding any translocation between Italy and Sicily. Information on genetic variability and population structure is being used to implement the Italian Action Plan for L. corsicanus.

Identification and genetic diversity in phytoplasmas associated with diseases of cassava and other agronomic relevant crops in south-east Asia and Latin America

Identification and genetic diversity of phytoplasmas infecting tropical plant species, selected among those most agronomically relevant in South-east Asia and Latin America were studied. Correlation between evolutionary divergence of relevant phytoplasma strains and their geographic distribution by comparison on homologous genes of phytoplasma strains detected in the same or related plant species in other geographical areas worldwide was achieved. Molecular diversity was studied on genes coding ribosomal proteins, groEL, tuf and amp besides phytoplasma 16S rRNA. Selected samples infected by phytoplasmas belonging to diverse ribosomal groups were also studied by in silico RFLP followed by phylogenetic analyses. Moreover a partial genome annotation of a ‘Ca. P. brasiliense’ strain was done towards future application for epidemiological studies. Phytoplasma presence in cassava showing frog skin (CFSD) and witches’ broom (CWB) diseases in Costa Rica - Paraguay and in Vietnam – Thailand, respectively, was evaluated. In both cases, the diseases were associated with phytoplasmas related to aster yellows, apple proliferation and “stolbur” groups, while only phytoplasma related to X-disease group in CFSD, and to hibiscus witches’ broom, elm yellows and clover proliferation groups in CWB. Variability was found among strains belonging to the same ribosomal group but having different geographic origin and associated with different disease. Additionally, a dodder transmission assay to elucidate the role of phytoplasmas in CWB disease was carried out, and resulted in typical phytoplasma symptoms in periwinkle plants associated with the presence of aster yellows-related strains. Lethal wilt disease, a severe disease of oil palm in Colombia that is spreading throughout South America was also studied. Phytoplasmas were detected in symptomatic oil palm and identified as ‘Ca. P. asteris’, ribosomal subgroup 16SrI-B, and were distinguished from other aster yellows phytoplasmas used as reference strains; in particular, from an aster yellows strain infecting corn in the same country.

Influence of plant structure, cultural pratices and environmental conditions on the development of the bacterial canker of kiwifruits

Italy has a preeminent rank in kiwifruit industry, being the first exporter and the second largest producer after China. However, in the last years kiwifruit yields and the total cultivated area considerably decreased, due to the pandemic spread of the bacterial canker caused by Pseudomonas syringae pv. actinidiae (Psa). Several climatic conditions and cultural practices affect the development of the bacterial canker. This research work focused on the impact of agricultural practices and microclimate conditions on the incidence and epidemiology of Psa in the orchard. Therefore, the effect of fertilization, irrigation, use of bio-regulators, rootstock, training system and pruning were examined. The effect of different tunnel systems was analyzed as well, to study the plant-pathogen interaction. Considering the importance of insects as vectors in other pathosystems, the role of Metcalfa pruinosa in the spread of the bacterial canker was investigated in controlled conditions. In addition, quality and storage properties of fruits from infected plants were assessed. The study of all these aspects of the agronomic practices is useful to define a strategy to limit the bacterial diffusion in the orchard. Overall, excess nitrogen fertilization, water stress, stagnant water supplies, pruning before summer and the high number of Metcalfa pruinosa increased the Psa incidence. In contrast, tunnel covers may be useful for the control of the disease, with special attention to the kind of material.

Exploring mediterranean durum wheat wild relatives and elite diversity panel for future breeding

Durum wheat (Triticum durum) is an important crop that has been used for millennia for human consumption, and modern breeding can take advantage of the wide variability useful for the adaptation to new challenges. Novel beneficial alleles can be found in wild relatives and landraces thus enhancing crop adaptation to many biotic and abiotic stresses. This dissertation considers the source of variability from both before and after wheat domestication, that caused a loss of potentially useful alleles. Chapter 1. is the thesis introduction, which outlines the importance of wheat in the world, providing an historical overview of the domestication, the evolution mechanisms that led to the current forms of durum wheat and the use of wild relatives as a source of germplasm for future breeding programs is crucial. Moreover, the emergence of Z. tritici has been considered as the main pathogen of wheat since it contains extremely high levels of genetic variability and is thus difficult to control. Chapter 2. Considers the contribution of the phenotypic diversity of 242 accessions of Aegilops tauschii from the Open Wild Wheat Consortium, involved in wheat domestication, provided with whole-genome resequencing. The accessions were phenotyped both in the field and in controlled conditions and A k-mer-based GWAS was performed to identify genomic regions involved in useful traits. Chapter 3. Describes the genetic basis of resistance to Z. tritici in a durum wheat elite diversity panel representative of the germplasm bred in Mediterranean. Quantitative trait loci (QTL) analysis results revealed several loci involved in the STB response that were found in several chromosome regions with a high infection rate. The genomic regions associated with STB resistance identified in this study could be of interest for marker assisted selection (MAS) in durum wheat breeding programs.

Essays in the Economics of the Family and Cultural Transmission

My research aims at identifying the role cultural-ethnic traits play in marriage choices and at uncovering the implications of marital sorting on consequent intra-household decisions. From different perspectives, this thesis focuses on intermarriages, within the Italian marriage market. In the first chapter, I explore the role of ethnic endogamy on marital instability. I document the existence of a positive differential in marital instability of interethnic marriages compared to homogeneous ones and I demonstrate that genetic and ethnolinguistic measures of cultural diversity are informative about the incidence of marital dissolution. The second chapter investigates a novel channel, which explains the differential in household stability and investments across family types: cultural socialization of children. I propose a marital matching model along cultural-ethnic lines, to study the process of family formation and intra-household decision making in a context where ethnic differences between spouses potentially matter both in terms of preferences and technologies for household production. The observed intermarriage, fertility, separation and socialization rates are in line with theoretical predictions and they are consistent with strong preferences of parents toward cultural socialization of children to their own ethnic identity. In the third chapter, I propose and estimate a marital matching model along ethnic lines. I argue that gains to intermarriage depend on both cultural preferences and legal status motives. Taking advantage of the exogenous EU enlargements to East European countries in 2004 and 2007, I show that gains to intermarriage of East European migrants significantly decrease in response to the acquisition of the legal status. The final chapter aims to understand whether judicial decisions respond to the ethnic identity of spouses and what incentives those judgments are guided, by looking at separation and divorce sentences. Studying the legal custody assignment of children, I document a significant differential interacting mothers’ ethnicities with the family type.

Relationships between plant diversity and environmental heterogeneity in rupicolous grasslands on gypsum. The case study of Alysso-Sedion albi (Habitat 6110).

Plant communities on weathered rock and outcrops are characterized by high values in species richness (Dengler 2006) and often persist on small and fragmented surfaces. Yet very few studies have examined the relationships between heterogeneity and plant diversity at small scales, in particular in poor-nutrient and low productive environment (Shmida and Wilson 1985, Lundholm 2003). In order to assess these relationships both in space and time in relationship, two different approaches were employed in the present study, in two gypsum outcrops of Northern Apennine. Diachronic and synchronic samplings from April 2012 to March 2013 were performed. A 50x50 cm plot was used in both samplings such as the sampling unit base. The diachronic survey aims to investigate seasonal patterning of plant diversity by the use of images analysis techniques integrated with field data and considering also seasonal climatic trend, the substrate quality and its variation in time. The purpose of the further, synchronic sampling was to describe plant diversity pattern as a function of the environmental heterogeneity meaning in substrate typologies, soil depth and topographic features. Results showed that responses of diversity pattern depend both on the resources availability, environmental heterogeneity and the manner in which the different taxonomic group access to them during the year. Species richness and Shannon diversity were positively affected by increasing in substrate heterogeneity. Furthermore a good turnover in seasonal species occurrence was detected. This vegetation may be described by the coexistence of three groups of species which created a gradient from early colonization stages, characterized by greater slope and predominance of bare rock, gradually to situation of more developed soil.