151
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Browett S, McHugo G, Richardson IW, Magee DA, Park SDE, Fahey AG, Kearney JF, Correia CN, Randhawa IAS, MacHugh DE. Genomic Characterisation of the Indigenous Irish Kerry Cattle Breed. Front Genet 2018. [PMID: 29520297 PMCID: PMC5827531 DOI: 10.3389/fgene.2018.00051] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Kerry cattle are an endangered landrace heritage breed of cultural importance to Ireland. In the present study we have used genome-wide SNP array data to evaluate genomic diversity within the Kerry population and between Kerry cattle and other European breeds. Patterns of genetic differentiation and gene flow among breeds using phylogenetic trees with ancestry graphs highlighted historical gene flow from the British Shorthorn breed into the ancestral population of modern Kerry cattle. Principal component analysis (PCA) and genetic clustering emphasised the genetic distinctiveness of Kerry cattle relative to comparator British and European cattle breeds. Modelling of genetic effective population size (Ne) revealed a demographic trend of diminishing Ne over time and that recent estimated Ne values for the Kerry breed may be less than the threshold for sustainable genetic conservation. In addition, analysis of genome-wide autozygosity (FROH) showed that genomic inbreeding has increased significantly during the 20 years between 1992 and 2012. Finally, signatures of selection revealed genomic regions subject to natural and artificial selection as Kerry cattle adapted to the climate, physical geography and agro-ecology of southwest Ireland.
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Affiliation(s)
- Sam Browett
- Ecosystems and Environment Research Centre, School of Environment and Life Sciences, University of Salford, Salford, United Kingdom
| | - Gillian McHugo
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | | | - David A Magee
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | | | - Alan G Fahey
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | | | - Carolina N Correia
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland
| | - Imtiaz A S Randhawa
- Sydney School of Veterinary Science, The University of Sydney, Camden, NSW, Australia
| | - David E MacHugh
- Animal Genomics Laboratory, UCD School of Agriculture and Food Science, University College Dublin, Dublin, Ireland.,UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin, Ireland
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152
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Ceballos FC, Hazelhurst S, Ramsay M. Assessing runs of Homozygosity: a comparison of SNP Array and whole genome sequence low coverage data. BMC Genomics 2018; 19:106. [PMID: 29378520 PMCID: PMC5789638 DOI: 10.1186/s12864-018-4489-0] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 01/19/2018] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND Runs of Homozygosity (ROH) are genomic regions where identical haplotypes are inherited from each parent. Since their first detection due to technological advances in the late 1990s, ROHs have been shedding light on human population history and deciphering the genetic basis of monogenic and complex traits and diseases. ROH studies have predominantly exploited SNP array data, but are gradually moving to whole genome sequence (WGS) data as it becomes available. WGS data, covering more genetic variability, can add value to ROH studies, but require additional considerations during analysis. RESULTS Using SNP array and low coverage WGS data from 1885 individuals from 20 world populations, our aims were to compare ROH from the two datasets and to establish software conditions to get comparable results, thus providing guidelines for combining disparate datasets in joint ROH analyses. By allowing heterozygous SNPs per window, using the PLINK homozygosity function and non-parametric analysis, we were able to obtain non-significant differences in number ROH, mean ROH size and total sum of ROH between data sets using the different technologies for almost all populations. CONCLUSIONS By allowing 3 heterozygous SNPs per ROH when dealing with WGS low coverage data, it is possible to establish meaningful comparisons between data using SNP array and WGS low coverage technologies.
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Affiliation(s)
- Francisco C Ceballos
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Scott Hazelhurst
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- School of Electrical & Information Engineering, University of the Witwatersrand, Johannesburg, South Africa
| | - Michèle Ramsay
- Sydney Brenner Institute for Molecular Bioscience, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Division of Human Genetics, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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153
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Genomic diversity and population structure of three autochthonous Greek sheep breeds assessed with genome-wide DNA arrays. Mol Genet Genomics 2018; 293:753-768. [PMID: 29372305 DOI: 10.1007/s00438-018-1421-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 01/17/2018] [Indexed: 12/13/2022]
Abstract
In the present study, genome-wide genotyping was applied to characterize the genetic diversity and population structure of three autochthonous Greek breeds: Boutsko, Karagouniko and Chios. Dairy sheep are among the most significant livestock species in Greece numbering approximately 9 million animals which are characterized by large phenotypic variation and reared under various farming systems. A total of 96 animals were genotyped with the Illumina's OvineSNP50K microarray beadchip, to study the population structure of the breeds and develop a specialized panel of single-nucleotide polymorphisms (SNPs), which could distinguish one breed from the others. Quality control on the dataset resulted in 46,125 SNPs, which were used to evaluate the genetic structure of the breeds. Population structure was assessed through principal component analysis (PCA) and admixture analysis, whereas inbreeding was estimated based on runs of homozygosity (ROHs) coefficients, genomic relationship matrix inbreeding coefficients (FGRM) and patterns of linkage disequilibrium (LD). Associations between SNPs and breeds were analyzed with different inheritance models, to identify SNPs that distinguish among the breeds. Results showed high levels of genetic heterogeneity in the three breeds. Genetic distances among breeds were modest, despite their different ancestries. Chios and Karagouniko breeds were more genetically related to each other compared to Boutsko. Analysis revealed 3802 candidate SNPs that can be used to identify two-breed crosses and purebred animals. The present study provides, for the first time, data on the genetic background of three Greek indigenous dairy sheep breeds as well as a specialized marker panel that can be applied for traceability purposes as well as targeted genetic improvement schemes and conservation programs.
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154
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Mastrangelo S, Ciani E, Sardina MT, Sottile G, Pilla F, Portolano B. Runs of homozygosity reveal genome-wide autozygosity in Italian sheep breeds. Anim Genet 2018; 49:71-81. [PMID: 29333609 DOI: 10.1111/age.12634] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/20/2017] [Indexed: 02/03/2023]
Abstract
The availability of dense single nucleotide polymorphism (SNP) assays allows for the determination of autozygous segments based on runs of consecutive homozygous genotypes (ROH). The aim of the present study was to investigate the occurrence and distribution of ROH in 21 Italian sheep breeds using medium-density SNP genotypes in order to characterize autozygosity and identify genomic regions that frequently appeared in ROH within individuals, namely ROH islands. After filtering, the final number of animals and SNPs retained for analyses were 502 and 46 277 respectively. A total of 12 302 ROH were identified. The mean number of ROH per breed ranged from 10.58 (Comisana) to 44.54 (Valle del Belice). The average length of ROH across breeds was 4.55 Mb and ranged from 3.85 Mb (Biellese) to 5.51 Mb (Leccese). Valle del Belice showed the highest value of inbreeding on the basis of ROH (FROH = 0.099), whereas Comisana showed the lowest (FROH = 0.016), and high standard deviation values revealed high variability in autozygosity levels within each breed. Differences also existed in the length of ROH. Analysis of the distribution of ROH according to their size showed that, for all breeds, the majority of the detected ROH were <10 Mb in length, with a few long ROH >25 Mb. The levels of ROH that we estimated here reflect the inbreeding history of the investigated sheep breeds. These results also highlight that ancient and recent inbreeding have had an impact on the genome of the Italian sheep breeds and suggest that several animals have experienced recent autozygosity events. Comisana and Bergamasca appeared as the less consanguineous breeds, whereas Barbaresca, Leccese and Valle del Belice showed ROH patterns typically produced by recent inbreeding. Moreover, within the genomic regions most commonly associated with ROH, several candidate genes were detected.
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Affiliation(s)
- S Mastrangelo
- Dipartimento Scienze Agrarie, Alimentari e Forestali, University of Palermo, 90128, Palermo, Italy
| | - E Ciani
- Dipartimento di Bioscienze, Biotecnologie e Biofarmaceutica University of Bari, 70124, Bari, Italy
| | - M T Sardina
- Dipartimento Scienze Agrarie, Alimentari e Forestali, University of Palermo, 90128, Palermo, Italy
| | - G Sottile
- Dipartimento Scienze Economiche, Aziendali e Statistiche, University of Palermo, 90128, Palermo, Italy
| | - F Pilla
- Dipartimento Agricoltura, Ambiente e Alimenti, University of Molise, 86100, Campobasso, Italy
| | - B Portolano
- Dipartimento Scienze Agrarie, Alimentari e Forestali, University of Palermo, 90128, Palermo, Italy
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155
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Peripolli E, Stafuzza NB, Munari DP, Lima ALF, Irgang R, Machado MA, Panetto JCDC, Ventura RV, Baldi F, da Silva MVGB. Assessment of runs of homozygosity islands and estimates of genomic inbreeding in Gyr (Bos indicus) dairy cattle. BMC Genomics 2018; 19:34. [PMID: 29316879 PMCID: PMC5759835 DOI: 10.1186/s12864-017-4365-3] [Citation(s) in RCA: 90] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 12/04/2017] [Indexed: 11/10/2022] Open
Abstract
Background Runs of homozygosity (ROH) are continuous homozygous segments of the DNA sequence. They have been applied to quantify individual autozygosity and used as a potential inbreeding measure in livestock species. The aim of the present study was (i) to investigate genome-wide autozygosity to identify and characterize ROH patterns in Gyr dairy cattle genome; (ii) identify ROH islands for gene content and enrichment in segments shared by more than 50% of the samples, and (iii) compare estimates of molecular inbreeding calculated from ROH (FROH), genomic relationship matrix approach (FGRM) and based on the observed versus expected number of homozygous genotypes (FHOM), and from pedigree-based coefficient (FPED). Results ROH were identified in all animals, with an average number of 55.12 ± 10.37 segments and a mean length of 3.17 Mb. Short segments (ROH1–2 Mb) were abundant through the genomes, which accounted for 60% of all segments identified, even though the proportion of the genome covered by them was relatively small. The findings obtained in this study suggest that on average 7.01% (175.28 Mb) of the genome of this population is autozygous. Overlapping ROH were evident across the genomes and 14 regions were identified with ROH frequencies exceeding 50% of the whole population. Genes associated with lactation (TRAPPC9), milk yield and composition (IRS2 and ANG), and heat adaptation (HSF1, HSPB1, and HSPE1), were identified. Inbreeding coefficients were estimated through the application of FROH, FGRM, FHOM, and FPED approaches. FPED estimates ranged from 0.00 to 0.327 and FROH from 0.001 to 0.201. Low to moderate correlations were observed between FPED-FROH and FGRM-FROH, with values ranging from −0.11 to 0.51. Low to high correlations were observed between FROH-FHOM and moderate between FPED-FHOM and FGRM-FHOM. Correlations between FROH from different lengths and FPED gradually increased with ROH length. Conclusions Genes inside ROH islands suggest a strong selection for dairy traits and enrichment for Gyr cattle environmental adaptation. Furthermore, low FPED-FROH correlations for small segments indicate that FPED estimates are not the most suitable method to capture ancient inbreeding. The existence of a moderate correlation between larger ROH indicates that FROH can be used as an alternative to inbreeding estimates in the absence of pedigree records. Electronic supplementary material The online version of this article (10.1186/s12864-017-4365-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Elisa Peripolli
- Faculdade de Ciências Agrárias e Veterinárias, Departamento de Zootecnia, UNESP Univ Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, 14884-900, Brazil
| | - Nedenia Bonvino Stafuzza
- Faculdade de Ciências Agrárias e Veterinárias, Departamento de Ciências Exatas, UNESP Univ Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, 14884-900, Brazil
| | - Danísio Prado Munari
- Faculdade de Ciências Agrárias e Veterinárias, Departamento de Ciências Exatas, UNESP Univ Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, 14884-900, Brazil.,Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ), Lago Sul, 71605-001, Brazil
| | - André Luís Ferreira Lima
- Centro de Ciências Agrárias, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, 88034-000, Brazil
| | - Renato Irgang
- Centro de Ciências Agrárias, Departamento de Zootecnia e Desenvolvimento Rural, Universidade Federal de Santa Catarina, Florianópolis, 88034-000, Brazil
| | - Marco Antonio Machado
- Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ), Lago Sul, 71605-001, Brazil.,Embrapa Gado de Leite, Juiz de Fora, 36038-330, Brazil
| | | | - Ricardo Vieira Ventura
- Faculdade de Zootecnia e Engenharia de Alimentos, Universidade de São Paulo, Pirassununga, 13635-900, Brazil.,Beef Improvement Opportunities, Elora, ON, N0B 1S0, Canada.,University of Guelph, Centre for Genetic Improvement of Livestock, ABScBG, Guelph, N1G 2W1, Canada
| | - Fernando Baldi
- Faculdade de Ciências Agrárias e Veterinárias, Departamento de Zootecnia, UNESP Univ Estadual Paulista Júlio de Mesquita Filho, Jaboticabal, 14884-900, Brazil.,Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ), Lago Sul, 71605-001, Brazil
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156
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Genome-wide identification of runs of homozygosity islands and associated genes in local dairy cattle breeds. Animal 2018; 12:2480-2488. [DOI: 10.1017/s1751731118000629] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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157
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Blant A, Kwong M, Szpiech ZA, Pemberton TJ. Weighted likelihood inference of genomic autozygosity patterns in dense genotype data. BMC Genomics 2017; 18:928. [PMID: 29191164 PMCID: PMC5709839 DOI: 10.1186/s12864-017-4312-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 11/16/2017] [Indexed: 12/14/2022] Open
Abstract
Background Genomic regions of autozygosity (ROA) arise when an individual is homozygous for haplotypes inherited identical-by-descent from ancestors shared by both parents. Over the past decade, they have gained importance for understanding evolutionary history and the genetic basis of complex diseases and traits. However, methods to infer ROA in dense genotype data have not evolved in step with advances in genome technology that now enable us to rapidly create large high-resolution genotype datasets, limiting our ability to investigate their constituent ROA patterns. Methods We report a weighted likelihood approach for inferring ROA in dense genotype data that accounts for autocorrelation among genotyped positions and the possibilities of unobserved mutation and recombination events, and variability in the confidence of individual genotype calls in whole genome sequence (WGS) data. Results Forward-time genetic simulations under two demographic scenarios that reflect situations where inbreeding and its effect on fitness are of interest suggest this approach is better powered than existing state-of-the-art methods to infer ROA at marker densities consistent with WGS and popular microarray genotyping platforms used in human and non-human studies. Moreover, we present evidence that suggests this approach is able to distinguish ROA arising via consanguinity from ROA arising via endogamy. Using subsets of The 1000 Genomes Project Phase 3 data we show that, relative to WGS, intermediate and long ROA are captured robustly with popular microarray platforms, while detection of short ROA is more variable and improves with marker density. Worldwide ROA patterns inferred from WGS data are found to accord well with those previously reported on the basis of microarray genotype data. Finally, we highlight the potential of this approach to detect genomic regions enriched for autozygosity signals in one group relative to another based upon comparisons of per-individual autozygosity likelihoods instead of inferred ROA frequencies. Conclusions This weighted likelihood ROA inference approach can assist population- and disease-geneticists working with a wide variety of data types and species to explore ROA patterns and to identify genomic regions with differential ROA signals among groups, thereby advancing our understanding of evolutionary history and the role of recessive variation in phenotypic variation and disease. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-4312-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alexandra Blant
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada
| | - Michelle Kwong
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada
| | - Zachary A Szpiech
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA, USA
| | - Trevor J Pemberton
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada.
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158
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Mastrangelo S, Tolone M, Sardina MT, Sottile G, Sutera AM, Di Gerlando R, Portolano B. Genome-wide scan for runs of homozygosity identifies potential candidate genes associated with local adaptation in Valle del Belice sheep. Genet Sel Evol 2017; 49:84. [PMID: 29137622 PMCID: PMC5684758 DOI: 10.1186/s12711-017-0360-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 11/07/2017] [Indexed: 11/23/2022] Open
Abstract
Background Because very large numbers of single nucleotide polymorphisms (SNPs) are now available throughout the genome, they are particularly suitable for the detection of genomic regions where a reduction in heterozygosity has occurred and they offer new opportunities to improve the accuracy of inbreeding (\documentclass[12pt]{minimal}
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\begin{document}$$F$$\end{document}F) estimates. Runs of homozygosity (ROH) are contiguous lengths of homozygous segments of the genome where the two haplotypes inherited from the parents are identical. Here, we investigated the occurrence and distribution of ROH using a medium-dense SNP panel to characterize autozygosity in 516 Valle del Belice sheep and to identify the genomic regions with high ROH frequencies. Results We identified 11,629 ROH and all individuals displayed at least one ROH longer than 1 Mb. The mean value of \documentclass[12pt]{minimal}
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\begin{document}$$F$$\end{document}F estimated from ROH longer than1 Mb was 0.084 ± 0.061. ROH that were shorter than 10 Mb predominated. The highest and lowest coverages of Ovis aries chromosomes (OAR) by ROH were on OAR24 and OAR1, respectively. The number of ROH per chromosome length displayed a specific pattern, with higher values for the first three chromosomes. Both number of ROH and length of the genome covered by ROH varied considerably between animals. Two hundred and thirty-nine SNPs were considered as candidate markers that may be under directional selection and we identified 107 potential candidate genes. Six genomic regions located on six chromosomes, corresponding to ROH islands, are presented as hotspots of autozygosity, which frequently coincided with regions of medium recombination rate. According to the KEGG database, most of these genes were involved in multiple signaling and signal transduction pathways in a wide variety of cellular and biochemical processes. A genome scan revealed the presence of ROH islands in genomic regions that harbor candidate genes for selection in response to environmental stress and which underlie local adaptation. Conclusions These results suggest that natural selection has, at least partially, a role in shaping the genome of Valle del Belice sheep and that ROH in the ovine genome may help to detect genomic regions involved in the determinism of traits under selection. Electronic supplementary material The online version of this article (10.1186/s12711-017-0360-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Salvatore Mastrangelo
- Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, 90128, Palermo, Italy.
| | - Marco Tolone
- Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, 90128, Palermo, Italy
| | - Maria T Sardina
- Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, 90128, Palermo, Italy
| | - Gianluca Sottile
- Dipartimento di Scienze Economiche, Aziendali e Statistiche, Università degli Studi di Palermo, 90128, Palermo, Italy
| | - Anna M Sutera
- Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, 90128, Palermo, Italy
| | - Rosalia Di Gerlando
- Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, 90128, Palermo, Italy
| | - Baldassare Portolano
- Dipartimento Scienze Agrarie, Alimentari e Forestali, Università degli Studi di Palermo, 90128, Palermo, Italy
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