Search results for "Homozygosity"
showing 10 items of 42 documents
Gametic and somatic embryogenesis through in vitro anther culture of different Citrus genotypes
2015
Abstract: In vitro tissue culture represents a useful technique for advancing Citrus breeding and propagation. Among in vitro regeneration systems, anther culture is commonly used to produce haploids and doubled haploids for a fast-track producing homozygous lines, in comparison with the traditional self-pollination approach, which involves several generations of selfing. In addition, anthers culture can produce somatic embryos that can also be used for clonal propagation. In this study, two thermal shocks were applied to the anthers of six Citrus genotypes (two clementine and four sweet oranges), just after they were put in culture. The response obtained was different depending on the geno…
Microspore embryogenesis induced through in vitro anther culture of almond (Prunus dulcis Mill.)
2016
Anther culture is one of the most widely used methods to induce gametic embryogenesis. The aim of this investigation was to induce microspore embryogenesis in almond (Prunus dulcis Mill.), through this technique. Anthers were cultured at the vacuolated developmental stage, and seven cultivars, two culture media and two temperature treatments were assessed. Although evidence of the microspore induction was observed in all the genotypes and treatments tested (symmetrical nucleus division and multinucleated structures), calli were produced merely by anthers cultured in the medium P and the regeneration of embryos was detected only in anthers of the cultivars Filippo Ceo, Lauranne and Genco, pl…
A population genomics analysis of the native Irish Galway sheep breed.
2019
SUMMARYThe Galway sheep population is the only native Irish sheep breed and represents an important livestock genetic resource, which is currently categorised as “at-risk”. In the present study, comparative population genomics analyses of Galway sheep and other sheep populations of European origin were used to investigate the microevolution and recent genetic history of the breed. These analyses support the hypothesis that British Leicester sheep were used in the formation of the Galway breed and suggest more recent gene flow from the Suffolk sheep breed. When compared to conventional and endangered breeds, the Galway breed was intermediate in effective population size, genomic inbreeding a…
Refining the genetic structure and relationships of European cattle breeds through meta-analysis of worldwide genomic SNP data, focusing on Italian c…
2020
AbstractThe availability of genotyping assays has allowed the detailed evaluation of cattle genetic diversity worldwide. However, these comprehensive studies did not include some local European populations, including autochthonous Italian cattle. In this study, we assembled a large-scale, genome-wide dataset of single nucleotide polymorphisms scored in 3,283 individuals from 205 cattle populations worldwide to assess genome-wide autozygosity and understand better the genetic relationships among these populations. We prioritized European cattle, with a special focus on Italian breeds. Moderate differences in estimates of molecular inbreeding calculated from runs of homozygosity (FROH) were o…
Genome-wide analyses reveal the regions involved in the phenotypic diversity in Sicilian pigs.
2019
Nero Siciliano (Sicilian Black, SB) is a local pig breed generally of uniform black color. In addition to this officially recognized breed, there are animals showing morphological characteristics resembling the SB but with gray hair (Sicilian Grey, SG). The SG, compared with the SB, also shows a more compact structure with greater transverse diameters, higher average daily gains and lower thickness of the back fat. In this study, using the Illumina PorcineSNP60 BeadChip, we run genome-wide analyses to identify regions that may explain the phenotypic differences between SB (n = 21) and SG (n = 27) individuals. Combining the results of the two case–control approaches (GWAS and FST), we identi…
Genome-wide scan for runs of homozygosity identifies potential candidate genes associated with local adaptation in Valle del Belice sheep
2017
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} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \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 t…
Runs of homozygosity reveal genome-wide autozygosity in Italian sheep breeds
2018
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 B…
Novel and known signals of selection for fat deposition in domestic sheep breeds from Africa and Eurasia
2018
International audience; Genomic regions subjected to selection frequently show signatures such as within-population reduced nucleotide diversity and outlier values of differentiation among differentially selected populations. In this study, we analyzed 50K SNP genotype data of 373 animals belonging to 23 sheep breeds of different geographic origins using the Rsb (extended haplotype homozygosity) and FST statistical approaches, to identify loci associated with the fat-tail phenotype. We also checked if these putative selection signatures overlapped with regions of high-homozygosity (ROH). The analyses identified novel signals and confirmed the presence of selection signature in genomic regio…
Genome-wide assessment of diversity and differentiation between original and modern Brown cattle populations
2020
Identifying genomic regions involved in the differences between breeds can provide information on genes that are under the influence of both artificial and natural selection. The aim of this study was to assess the genetic diversity and differentiation among four different Brown cattle populations (two original vs. two modern populations) and to characterize the distribution of runs of homozygosity (ROH) islands using the Illumina Bovine SNP50 BeadChip genotyping data. After quality control, 34 735 SNPs and 106 animals were retained for the analyses. Larger heterogeneity was highlighted for the original populations. Patterns of genetic differentiation, multidimensional scaling, and the neig…
Conservation status and historical relatedness of Italian cattle breeds
2018
Background In the last 50 years, the diversity of cattle breeds has experienced a severe contraction. However, in spite of the growing diffusion of cosmopolite specialized breeds, several local cattle breeds are still farmed in Italy. Genetic characterization of breeds represents an essential step to guide decisions in the management of farm animal genetic resources. The aim of this work was to provide a high-resolution representation of the genome-wide diversity and population structure of Italian local cattle breeds using a medium-density single nucleotide polymorphism (SNP) array. Results After quality control filtering, the dataset included 31,013 SNPs for 800 samples from 32 breeds. Ou…