scholarly journals Evolutionary processes involved in the emergence and expansion of an atypical O. sativa group in Madagascar.

2020 ◽  
Author(s):  
Nourollah Ahmadi ◽  
Alain Ramanantsoanirina ◽  
João D. Santos ◽  
Julien Frouin ◽  
Tendro Radanielina
Keyword(s):  
Genetic Diversity ◽  
Gene Diversity ◽  
Indian Subcontinent ◽  
Principal Component ◽  
Feature Space ◽  
Whole Genome ◽  
Human Settlement ◽  
Evolutionary Processes ◽  
Assignment Method ◽  
Asian Rice

Abstract Understanding crops genetic diversity and the evolutionary processes that accompanied their world-wide spread is useful for designing effective breeding strategies. Madagascar Island was one of the last major Old World areas where human settlement was accompanied by the introduction of Oryza sativa. Early studies had reported the presence in the island of a rice group specific to Madagascar. Using 24K SNP, we compared diversity patterns at the whole genome and at haplotypes (30 SNP-long segments along the genome) levels, between 620 Malagasy and 1,929 Asian rice accessions. The haplotypes level analysis aimed at identifying local genotypic variations, relative to the whole genome level, using a group assignment method that relies on kernel density estimation in a Principal Component Analysis feature space. Migration bottleneck had resulted in 10–25% reduction of diversity among the Malagasy representatives of indica (G1) and japonica (G6) populations. Compared to their Asian counterpart, G1 and G6 showed slightly lower indica and japonica introgressions, suggesting the latter population had undergone less recombinations when migration to the island occurred. The origins of G1 and G6 was delineated to XI-2 indica subpopulation from the Indian subcontinent and to tropical japonica from the Malay Archipelago, respectively. The Malagasy-specific group (Gm) had a rather high gene diversity and an original haplotype pattern: much lower share of indica haplotypes, and much higher share of Aus and japonica haplotypes than G1 and indica. Its emergence and expansion are most probably due to inter-group recombination facilitated by sympatry between indica-cAus admixes and “Bulu” type landraces of G6 in the highlands of Madagascar, and to human selection for adaptation to the lowland ecosystems of the highlands. Pattern of rice genetic diversity was also tightly associated with the history of human settlement in the island. Emergence of the Gm group is associated with the latest arrivals of Austronesians, who founded the Merina kingdom in the central highlands and developed lowland rice cultivation. As an intermediary form between Aus, indica and japonica, the three pillars of O. sativa domestication, Gm represents a very valuable genetic resource in breeding for adaptation to cold tolerance in tropical highlands.

scholarly journals Evolutionary Processes Involved in the Emergence and Expansion of an Atypical O. sativa Group in Madagascar

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nourollah Ahmadi ◽  
Alain Ramanantsoanirina ◽  
João D. Santos ◽  
Julien Frouin ◽  
Tendro Radanielina
Keyword(s):  
Genetic Diversity ◽  
Gene Diversity ◽  
Indian Subcontinent ◽  
Principal Component ◽  
Feature Space ◽  
Rice Cultivation ◽  
Lowland Rice ◽  
Whole Genome ◽  
Human Settlement ◽  
Evolutionary Processes

AbstractUnderstanding crops genetic diversity and the evolutionary processes that accompanied their worldwide spread is useful for designing effective breeding strategies. Madagascar Island was one of the last major Old World areas where human settlement brought the introduction of Oryza sativa. Early studies in the island had reported the presence of a rice group specific to Madagascar. Using 24 K SNP, we compared diversity patterns at the whole genome and at haplotype (30 SNP-long segments along the genome) levels, between 620 Malagasy and 1929 Asian rice accessions. The haplotype level analysis aimed at identifying local genotypic variations, relative to the whole genome level, using a group assignment method that relies on kernel density estimation in a Principal Component Analysis feature space. Migration bottleneck had resulted in 10–25% reduction of diversity among the Malagasy representatives of indica and japonica populations. Compared to their Asian counterpart, they showed slightly lower indica and japonica introgressions, suggesting the two populations had undergone less recombination when migration to the island occurred. The origins of the Malagasy indica and japonica groups were delineated to indica subpopulation from the Indian subcontinent and to tropical japonica from the Malay Archipelago, respectively. The Malagasy-specific group (Gm) had a rather high gene diversity and an original haplotype pattern: much lower share of indica haplotypes, and much higher share of Aus and japonica haplotypes than indica. Its emergence and expansion are most probably due to inter-group recombination facilitated by sympatry between indica-Aus admixes and “Bulu” type landraces of japonica in the central high plateaux of Madagascar, and to human selection for adaptation to the lowland rice cultivation. Pattern of rice genetic diversity was also tightly associated with the history of human settlement in the island. Emergence of the Gm group is associated with the latest arrivals of Austronesians, who founded the Merina kingdom in the high plateaux and developed lowland rice cultivation. As an intermediary form between Aus, indica and japonica, the three pillars of O. sativa domestication, Gm represents a very valuable genetic resource in breeding for adaptation to cold tolerance in tropical highlands. We proposed the name Rojo for this new rice group.

scholarly journals Evaluation of the genetic diversity of six Chinese indigenous chickens

2020 ◽  
Vol 33 (10) ◽  
pp. 1566-1572
Author(s):  
Yuzhu Sha ◽  
Caixia Gao ◽  
Meimei Liu ◽  
Shengguo Zhao
Keyword(s):  
Genetic Diversity ◽  
Genetic Resources ◽  
Indian Subcontinent ◽  
Coastal Region ◽  
Principal Component ◽  
Sharp Decrease ◽  
Haplotype Sharing ◽  
Indigenous Chickens ◽  
D Loop ◽  
Commercial Chickens

Objective: The extensive breeding of commercial chickens has led to a sharp decrease in the resources of many indigenous chickens, especially the indigenous chickens in the southeastern coastal region, which are on the verge of extinction, and the indigenous chickens in the northwestern region of China, which are also at risk. However, there are few reports on the evaluation of genetic diversity and conservation of genetic resources of indigenous chickens in remote areas in the Northwest of China.Methods: In the present study, the genetic diversity and phylogenetic relationship of six indigenous chickens from different regions were studied based on variation in mitochondrial DNA control region (D-loop), and the degree of introgression from commercial breeds into these chickens was determined by the amount of haplotype sharing between indigenous and commercial breeds.Results: Twenty-five polymorphic sites and 25 haplotypes were detected in 206 individuals. Principal component analysis showed that the Jingning chicken had the highest genetic diversity among the six indigenous chickens. According to the degree of introgression, the six indigenous breeds may be involved in haplotype sharing with commercial breeds, and the introgression from commercial chickens into the Haidong chicken is the most serious.Conclusion: The genetic uniqueness of indigenous chickens has been eroded, so it is necessary to consider the protection of their genetic resources. Phylogenetic analysis suggests that the six indigenous chickens have two major matrilineal origins: one from Yunnan or its surrounding areas in China and the other from the Indian subcontinent.

scholarly journals Development and Application of Novel Indel Markers in Flax (Linum Usitatissimum L.) Through Whole-genome Re-sequencing

2021 ◽  
Author(s):  
Hui Jiang ◽  
Gen Pan ◽  
Touming Liu ◽  
Li Chang ◽  
Siqi Huang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Principal Component ◽  
Snp Markers ◽  
Diversity Analysis ◽  
Whole Genome ◽  
Chromosome 2 ◽  
Sequencing Data ◽  
Single Nucleotide ◽  
Genetic Diversity Analysis ◽  
Indel Markers

Abstract Flax is an important oil and fibre crop grown in Northern Europe, Canada, India, and China. The development of molecular markers has accelerated the process of flax molecular breeding and has improved yield and quality. Presently, simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers in the whole genome have been developed for flax. However, the development of flax insertion/deletion (InDel) markers has not been reported. A total of 17,110 InDel markers were identified by comparing whole-genome re-sequencing data of two accessions (87-3 and 84-3) with the flax reference genome. The length of InDels ranged from 1–277 bp, with 1–15 bp accounting for the highest rate (95.55%). The most common InDels were in the form of single nucleotide (8840), dinucleotide (3700), and trinucleotide (1349), and chromosome 2 (1505) showed the highest number of InDels among flax chromosomes, while chromosome 10 (913) presented with the lowest number. From 17,110 InDel markers, 90 primers that were evenly distributed in the flax genome were selected. Thirty-two pairs of polymorphic primers were detected in two flax accessions, and the polymorphism rate was 40.70%. Furthermore, genetic diversity analysis, population structure and principal component analyse (PCA) divided 69 flax accessions into two categories, namely oilseed flax and fibre flax using 32 pairs of polymorphic primers. Additionally, correlation analysis showed that InDel-26 and InDel-81 were associated with oil content traits, and two candidate genes (lus10031535 and lus10025284) tightly linked to InDel-26 or InDel-81, might be involved in flax lipid biosynthesis and lipid metabolism. This study is the first to develop InDel markers based on re-sequencing in flax and clustered the markers into two well-separated groups for oil and fibre. The results demonstrated that InDel markers developed herein could be used for flax germplasm identification, genetic diversity analysis, and molecular marker-assisted breeding.

scholarly journals Genetic diversity analysis of Chinese plum (Prunus salicina L.) based on whole-genome resequencing

2021 ◽  
Vol 17 (3) ◽  
Author(s):  
Xiao Wei ◽  
Fei Shen ◽  
Qiuping Zhang ◽  
Ning Liu ◽  
Yuping Zhang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Principal Component ◽  
Private Allele ◽  
Whole Genome ◽  
Nucleotide Polymorphisms ◽  
Genome Resequencing ◽  
Cultivar Group ◽  
Prunus Salicina ◽  
Whole Genome Resequencing

AbstractChinese plum (Prunus salicina L.), also known as Japanese plum, is gaining importance because of its extensive genetic diversity and nutritional attributes that are beneficial for human health. Single-nucleotide polymorphisms (SNPs) are the most abundant form of genomic polymorphisms and are widely used in population genetics research. In this study, we constructed high-quality SNPs through whole-genome resequencing of 67 Prunus accessions with a depth of ~20× to evaluate the genome-level diversity and population structure. Phylogenetic analysis, principal component analysis, and population structure profiling indicated that the 67 plum accessions could be classified into four groups corresponding to their origin location, the southern cultivar group (SCG), the northern cultivar group (NCG), the foreign cultivar group (FG), and the mixed cultivar group (MG). Some cultivars from South China clustered with the other three groups. The genetic diversity indices including private allele number, observed heterozygosity, expected heterozygosity, and the nucleotide diversity of the SCG were higher than those of the NCG. Gene flow from the SCG to FG was also detected. Based on the distribution of wild resources, we concluded that the domestication center of origin of the Chinese plum was southwestern China. This study also provided genetic variation features and the population structure of Chinese plum cultivars, laying a foundation for breeders to use diverse germplasm and allelic variants to improve Chinese plum varieties.

scholarly journals Whole-Genome Sequencing of the NARO World Rice Core Collection (WRC) as the Basis for Diversity and Association Studies

2020 ◽  
Vol 61 (5) ◽  
pp. 922-932 ◽  
Author(s):  
N Tanaka ◽  
M Shenton ◽  
Y Kawahara ◽  
M Kumagai ◽  
H Sakai ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Core Collection ◽  
Sequence Data ◽  
Association Studies ◽  
Crop Improvement ◽  
Heading Date ◽  
Principal Component ◽  
Genome Wide Association Studies ◽  
Whole Genome ◽  
Population Structure Analysis

Abstract Genebanks provide access to diverse materials for crop improvement. To utilize and evaluate them effectively, core collections, such as the World Rice Core Collection (WRC) in the Genebank at the National Agriculture and Food Research Organization, have been developed. Because the WRC consists of 69 accessions with a high degree of genetic diversity, it has been used for >300 projects. To allow deeper investigation of existing WRC data and to further promote research using Genebank rice accessions, we performed whole-genome resequencing of these 69 accessions, examining their sequence variation by mapping against the Oryza sativa ssp. japonica Nipponbare genome. We obtained a total of 2,805,329 single nucleotide polymorphisms (SNPs) and 357,639 insertion–deletions. Based on the principal component analysis and population structure analysis of these data, the WRC can be classified into three major groups. We applied TASUKE, a multiple genome browser to visualize the different WRC genome sequences, and classified haplotype groups of genes affecting seed characteristics and heading date. TASUKE thus provides access to WRC genotypes as a tool for reverse genetics. We examined the suitability of the compact WRC population for genome-wide association studies (GWASs). Heading date, affected by a large number of quantitative trait loci (QTLs), was not associated with known genes, but several seed-related phenotypes were associated with known genes. Thus, for QTLs of strong effect, the compact WRC performed well in GWAS. This information enables us to understand genetic diversity in 37,000 rice accessions maintained in the Genebank and to find genes associated with different phenotypes. The sequence data have been deposited in DNA Data Bank of Japan Sequence Read Archive (DRA) (Supplementary Table S1).

scholarly journals Development of GBTS and KASP Panels for Genetic Diversity, Population Structure, and Fingerprinting of a Large Collection of Broccoli (Brassica oleracea L. var. italica) in China

2021 ◽  
Vol 12 ◽  
Author(s):  
Yusen Shen ◽  
Jiansheng Wang ◽  
Ranjan K. Shaw ◽  
Huifang Yu ◽  
Xiaoguang Sheng ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Brassica Oleracea ◽  
Structure Analysis ◽  
Genetic Relatedness ◽  
Gene Diversity ◽  
Principal Component ◽  
Resolving Power ◽  
Limited Information ◽  
Large Collection

Broccoli (Brassica oleracea var. italica) is one of the most important and nutritious vegetables widely cultivated in China. In the recent four decades, several improved varieties were bred and developed by Chinese breeders. However, the efforts for improvement of broccoli are hindered by limited information of genetic diversity and genetic relatedness contained within the available germplasms. This study evaluated the genetic diversity, genetic relationship, population structure, and fingerprinting of 372 accessions of broccoli representing most of the variability of broccoli in China. Millions of SNPs were identified by whole-genome sequencing of 23 representative broccoli genotypes. Through several stringent selection criteria, a total of 1,167 SNPs were selected to characterize genetic diversity and population structure. Of these markers, 1,067 SNPs were genotyped by target sequencing (GBTS), and 100 SNPs were genotyped by kompetitive allele specific PCR (KASP) assay. The average polymorphism information content (PIC) and expected heterozygosity (gene diversity) values were 0.33 and 0.42, respectively. Diversity analysis revealed the prevalence of low to moderate genetic diversity in the broccoli accessions indicating a narrow genetic base. Phylogenetic and principal component analyses revealed that the 372 accessions could be clustered into two main groups but with weak groupings. STRUCTURE analysis also suggested the presence of two subpopulations with weak genetic structure. Analysis of molecular variance (AMOVA) identified 13% variance among populations and 87% within populations revealing very low population differentiation, which could be attributed to massive gene flow and the reproductive biology of the crop. Based on high resolving power, a set of 28 KASP markers was chosen for DNA fingerprinting of the broccoli accessions for seed authentication and varietal identification. To the best of our knowledge, this is the first comprehensive study to measure diversity and population structure of a large collection of broccoli in China and also the first application of GBTS and KASP techniques in genetic characterization of broccoli. This work broadens the understanding of diversity, phylogeny, and population structure of a large collection of broccoli, which may enhance future breeding efforts to achieve higher productivity.

scholarly journals Genetic diversity within local and introduced cultivars of wheat (Triticum aestivum L.) grown under Mediterranean environment as revealed by AFLP markers

2019 ◽  
Vol 63 (1) ◽  
pp. 25-30
Author(s):  
Mohammed Imad Eddin Arabi ◽  
Amina Shoaib ◽  
Eyad Al-Shehadah ◽  
Mohammed Jawhar
Keyword(s):  
Genetic Diversity ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Principal Component ◽  
Triticum Aestivum L ◽  
Wheat Breeding ◽  
Aflp Markers ◽  
Group Method ◽  
Wheat Cultivars ◽  
Arithmetic Means

Information on genetic diversity among cultivars is critical in wheat improvement. In this work, heterogeneity within local and introduced cultivars of bread wheat grown in Syria was investigated using amplified fragment length polymorphism (AFLP) markers. The eight primer pairs were used to detect 177 polymorphic bands among the 21 cultivars resulting in an average of 22.13 (57.3%) polymorphic loci per primer pair. Major allelic frequency ranged from 0.50 to 0.75 with a mean 0.64, and estimated gene diversity was 0.45. Values of average polymorphic information content (PIC) for these markers were estimated to be 0.34. This low value might be attributed to the rigorous selection pressure aimed at cultivar purity and associated breeding practices. Dissimilarity values ranged from 0.32 to 0.66 with an average of 0.54, indicating that such techniques sample distinct genome regions. Three major subgroups of wheat cultivars were identified using the unweighted pair-group method with arithmetic means analysis (UPGMA), with all local cultivars falling into one cluster, which was confirmed by a principal component analysis (PCA). The narrow genetic diversity observed among Syrian wheat cultivars suggests the need of broadening the genetic base of wheat breeding materials, including local landraces.

scholarly journals Genetic Diversity and Population Structure of Didymella rabiei Affecting Chickpea in Ethiopia

2021 ◽  
Vol 7 (10) ◽  
pp. 820
Author(s):  
Gezahegne Getaneh ◽  
Tadele Tefera ◽  
Fikre Lemessa ◽  
Seid Ahmed ◽  
Tarekegn Fite ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Genetic Variation ◽  
Gene Diversity ◽  
Polymorphic Information Content ◽  
Ascochyta Blight ◽  
Geographic Origin ◽  
Principal Component ◽  
Internal Transcribed Spacer Region ◽  
Pathogen Populations

Ascochyta blight, also known as chickpea blight, which is caused by the fungal pathogen, Didymella rabiei, is an important disease affecting chickpea (Cicer arietinum L.) in many countries. We studied the genetic diversity and population structure of 96 D. rabiei isolates collected from three geographic populations in Ethiopia using simple sequence repeat (SSR) markers. We confirmed the genetic identity of 89 of the D. rabiei isolates by sequencing their rRNA internal transcribed spacer region genes. The chickpea blight pathogen isolates were genetically diverse, with a total of 51 alleles identified across 6 polymorphic SSR loci, which varied from 3 to 18 (average 8.5) alleles per SSR marker. The observed heterozygosity and expected heterozygosity ranged from 0.01 to 0.92 and 0.19 to 0.86, respectively. The mean polymorphic information content value of the D. rabiei populations was 0.58, with a mean gene diversity of 0.61 among loci. Gene flow (Nm = number of migrants) for the three populations of D. rabiei isolates ranged from 1.51 to 24.10 (average 6.2) migrants/cluster. However, the genetic variation between the D. rabiei populations was small (8%), with most of the variation occurring within populations (92%). Principal component analysis to visualize genetic variation showed that the D. rabiei isolates obtained from most of the chickpea samples formed roughly three groups on a two-dimensional coordinate plane. Similarly, the clustering of individuals into populations based on multi-locus genotypes (using Clumpak) grouped isolates into three clusters but with individual isolate admixtures. Hence, no clear geographic origin-based structuring of populations could be identified. To our knowledge, this is the first report of D. rabiei diversity in Ethiopia. Virulence studies should be conducted to develop chickpea varieties that are resistant to more aggressive pathogen populations.

scholarly journals Genetic Diversity and Structure Analysis of a Worldwide Collection of Faba bean (Vicia faba) Genotypes using ISSR Markers

2021 ◽  
Vol 25 (03) ◽  
pp. 683-691
Author(s):  
Ahmed A. Qahtan
Keyword(s):  
Genetic Diversity ◽  
Vicia Faba ◽  
Faba Bean ◽  
Gene Diversity ◽  
Principal Component ◽  
Issr Markers ◽  
Discrimination Power ◽  
Software Analysis ◽  
Inter Simple Sequence Repeats ◽  
Genetic Diversity And Structure

The success of breeding programs depends on the extent of genetic variability. Inter-simple sequence repeats (ISSR) have been widely utilized in investigations, including the characterization of many plant species genetically. This research aimed to examine both the genetic diversity and relationships of 92 faba bean (Vicia faba L.) genotypes from different geographical areas using ISSR markers. Eleven ISSR primers generated a total of 189 repeatable amplified bands, of which 109 were polymorphic. Values of polymorphism information content (PIC) and gene diversity averaged 0.3484 and 0.1438 and ranged 0.089–0.715 and 0.0742–0.2065, respectively. The studied accessions of faba bean plant differentiated into four main clusters, prevalently based on geographical origin through UPGMA clustering analysis and principal component analysis (PCA), deriving four major groupings based on pedigree and origin relationships. The STRUCTURE software analysis results were significantly aligned with the PCA and showed five main clusters; each one represents one continent. AMOVA showed high variation and differentiation among nations from different continents. The discrimination power of ISSR markers obtained in this study suggests that they could be used to examine the diversity of faba bean genotypes efficiently and precisely and encourage targeted crossing strategies. © 2021 Friends Science Publishers

scholarly journals Development and Application of Novel InDel Markers in Flax (Linum usitatissimum L.) Through Whole-Genome Re-Sequencing

2021 ◽  
Author(s):  
Hui Jiang ◽  
Gen Pan ◽  
Touming Liu ◽  
Li Chang ◽  
Siqi Huang ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Principal Component ◽  
Snp Markers ◽  
Diversity Analysis ◽  
Whole Genome ◽  
Chromosome 2 ◽  
Sequencing Data ◽  
Single Nucleotide ◽  
Genetic Diversity Analysis ◽  
Indel Markers

Abstract Flax is an important oil and fibre crop grown in Northern Europe, Canada, India, and China. The development of molecular markers has accelerated the process of flax molecular breeding and has improved yield and quality. Presently, simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers in the whole genome have been developed for flax. However, the development of flax insertion/deletion (InDel) markers has not been reported. A total of 17,110 InDel markers were identified by comparing whole-genome re-sequencing data of two accessions (87 − 3 and 84 − 3) with the flax reference genome. The length of InDels ranged from 1–277 bp, with 1–15 bp accounting for the highest rate (95.55%). The most common InDels were in the form of single nucleotide (8840), dinucleotide (3700), and trinucleotide (1349), and chromosome 2 (1505) showed the highest number of InDels among flax chromosomes, while chromosome 10 (913) presented with the lowest number. From 17,110 InDel markers, 90 primers that were evenly distributed in the flax genome were selected. Thirty-two pairs of polymorphic primers were detected in two flax accessions, and the polymorphism rate was 40.70%. Furthermore, genetic diversity analysis, population structure and principal component analyse (PCA) divided 69 flax accessions into two categories, namely oilseed flax and fibre flax using 32 pairs of polymorphic primers. Additionally, correlation analysis showed that InDel-26 and InDel-81 were associated with oil content traits, and two candidate genes (lus10031535 and lus10025284) tightly linked to InDel-26 or InDel-81, might be involved in flax lipid biosynthesis and lipid metabolism. This study is the first to develop InDel markers based on re-sequencing in flax and clustered the markers into two well-separated groups for oil and fibre. The results demonstrated that InDel markers developed herein could be used for flax germplasm identification, genetic diversity analysis, and molecular marker-assisted breeding.

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