scholarly journals THE DYNAMICS OF GENETIC VARIABILITY IN THREE GENERATIONS OF MASS SELECTION FOR FAST GROWTH IN AFRICAN CATFISH, Clarias gariepinus ASSESSED BY MICROSATELLITE MARKERS

2015 ◽  
Vol 10 (2) ◽  
pp. 113
Author(s):  
Imron Imron ◽  
Bambang Iswanto ◽  
Huria Marnis ◽  
Rommy Suprapto ◽  
Narita Syawalia Ridzwan
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Genetic Differentiation ◽  
Clarias Gariepinus ◽  
Breeding Program ◽  
Fixation Index ◽  
Mass Selection ◽  
African Catfish ◽  
Three Generations ◽  
Selection For

Selective breeding aiming at improving the performance of economically important traits acts by exploiting population’s phenotypic variance. Due to the relationship between phenotype and genotype, selection on phenotype may also affect the profile of genotype. This study was aimed to monitor the impact of three generations of mass selection for fast growth in African catfish, Clarias gariepinus, on genetic variability, assessed by microsatellite. A total of 350 fish representing four populations, namely a composite base population (G-0), selected lines of the first generation (G-1) to the third generation (G-3), were sampled. The samples were screened for their genetic diversity using five microsatellite loci1 namely cga01, cga02, cga03, cga05, and cga09. Several genetic parameters including number of allele (A), allelic richness (AR), observed (Ho) and expected (He) heterozygosity, and fixation index (Fis) were evaluated. The results showed that there was a slight increase in the value of diversity indices in the G-1 relative to the G-0 and to the other two generations. Among these parameters, the number of allele seemed to be the most sensitive parameter in detecting genetic changes. All populations experienced heterozygote deficit and positive fixation index indicating the phenomena of inbreeding. Overall, selection for growth for three generations in African catfish breeding program resulted in significant genetic differentiation between populations. Further, the level of genetic differentiation seemed to accumulate along with the number of generaton in breeding program. However, selection did not result in a decline in genetic diversity within population. A relatively short period of the program, along with the use a high number of broodstock (mating pairs) to produce each generation seems to be able to maintain the stability of genetic diversity of the population.

scholarly journals RESPONSE TO SELECTION FOR BODY WEIGHT IN THE THIRD GENERATION OF MASS SELECTION OF THE AFRICAN CATFISH (Clarias gariepinus) AT RESEARCH INSTITUTE FOR FISH BREEDING SUKAMANDI

2016 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Bambang Iswanto ◽  
Imron Imron ◽  
Huria Marnis ◽  
Rommy Suprapto
Keyword(s):  
Body Weight ◽  
Second Generation ◽  
Clarias Gariepinus ◽  
Mass Selection ◽  
African Catfish ◽  
Larval Rearing ◽  
Third Generation ◽  
Response To Selection ◽  
The Third ◽  
Selection For

Genetic improvement of the African catfish (Clarias gariepinus) in Indonesia for increasing growth performance has been conducted by Research Institute for Fish Breeding at Sukamandi through mass selection. Collection and characterizations of the founder populations, building the synthetic base population, first generation and second generation through mass selection were conducted during 2010-2013. Later, in 2014 it was followed by building the third generation. The present study aimed to find out the genetic gain in the third generation in term of response to selection for body weight. Fifty-two pairs of the selected (fast growing) individuals from the second generation were mated to produce the third generation. As a comparison, five pairs of average-sized individuals were mated to produce the control population, as a second generation representative. Larval rearing, nursery and grow-out phases were respectively held for 25 days in the aquaria, 30 days in the concrete ponds and 60 days in the concrete ponds. At the end of each phase, individual samplings of body weight were undertaken. The results showed that mean body weight of the third generation was higher than that of control population at the end of larval rearing phase (0.21 ± 0.26 g versus 0.20 ± 0.15 g), nursery phase (6.12 ± 2.93 g versus 5.80 ± 3.50 g) and grow-out phase (198.67 ± 82.82 g versus 165.22 ± 71.09 g). Those results revealed that response to selection for body weight of the third generation was positive, i.e. about 20.24% (33.45 g).

scholarly journals Genetic diversity and population structure of the African catfish, Clarias gariepinus (Burchell, 1822) in Kenya: implication for conservation and aquaculture – Corrigendum

2017 ◽  
Vol 147 (2) ◽  
Author(s):  
James E. Barasa ◽  
Sinebongo Mdyogolo ◽  
Romulus Abila ◽  
Johannes Paul Grobler ◽  
Robert A. Skilton ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Clarias Gariepinus ◽  
African Catfish

This Corrigendum does not have an abstract.

scholarly journals Analysis of Genetic Diversity in three Kazakh Sheep using 12 Microsatellites

2018 ◽  
Vol 7 (4.38) ◽  
pp. 122
Author(s):  
Kairat Dossybayev ◽  
Aizhan Mussayeva ◽  
Bakytzhan Bekmanov ◽  
Beibit Kulataev
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Mean Value ◽  
Fixation Index ◽  
Merino Sheep ◽  
Str Markers ◽  
Sheep Breeds ◽  
Str Loci ◽  
High Level ◽  
Two Populations

The genetic structure of three Kazakh sheep breeds was examined by using 12 microsatellite loci. A total of 144 alleles were detected from the 12 STR loci, with a mean value of 12.0. The highest allele diversity was found at the locus CSRD247 (16 alleles). PIC value showed that all studied STR markers are more informative and appropriate for genetic analysis of three Kazakh sheep populations. Beside of INRA006, all markers had high level of genetic variability. As Fixation index shows, the excess of the heterozygosity was observed only in loci MAF065. Obtained number of private alleles in Edilbai, Kazakh Arkhar Merino and Kazakh Fine-wool sheep were 25, 17 and 15 respectively. Genetic diversity was higher in Edilbai population than in other two populations. The genetic variability was lower in Kazakh Arkhar Merino sheep than in the Edilbai and Kazakh Fine-wool sheep breeds. The genetic distance was the largest between Edilbai and Kazakh Arkhar Merinos. Also, the moderate differentiation was observed between Edilbai and Kazakh Arkhar Merinos.   

scholarly journals Genetic diversity analysis of a Flax (Linum usitatissimum L.) global collection

2020 ◽  
Author(s):  
Ahasanul Hoque ◽  
Jason D. Fiedler ◽  
Mukhlesur Rahman
Keyword(s):  
Genetic Diversity ◽  
Linkage Disequilibrium ◽  
Genetic Differentiation ◽  
Genetic Gain ◽  
Mantel Test ◽  
Snp Markers ◽  
Breeding Program ◽  
Neighbor Joining ◽  
Breeding Lines ◽  
The North

Abstract Background A sustainable breeding program requires a minimum level of germplasm diversity to provide varied options for the selection of new breeding lines. To maximize genetic gain of the North Dakota State University (NDSU) flax breeding program, we aimed to increase the genetic diversity of its parental stocks by incorporating diverse genotypes. For this purpose, we analyzed the genetic diversity, linkage disequilibrium, and population sub-structure of 350 globally-distributed flax genotypes with 6,200 SNP markers Results All the genotypes tested clustered into seven sub-populations (P1 to P7) based on the admixture model and the output of neighbor-joining (NJ) tree analysis and principal coordinate analysis were in line with that of structure analysis. The largest sub-population separation arose from a cluster of NDSU/American genotypes with Turkish and Asian genotypes. All sub-populations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise F st comparison revealed a great degree of divergence ( F st > 0.25) between most of the combinations. A whole collection mantel test showed significant positive correlation (r = 0.30 and p < 0.01) between genetic and geographic distances, whereas it was non-significant for all sub-populations except P4 and P5 (r= 0.251, 0.349 respectively and p < 0.05). In the entire collection, the mean linkage disequilibrium was 0.03 and it decayed to its half maximum within < 21 kb distance. Conclusions To maximize genetic gain, hybridization between NDSU stock (P5) and Asian individuals (P6) are potentially the best option as genetic differentiation between them is highest ( F st > 0.50). In contrast, low genetic differentiation between P5 and P2 may enhance the accumulation of favorable alleles for oil and fiber upon crossing to develop dual purpose varieties. As each sub-population consists of many genotypes, a Neighbor-Joining tree assists to identify distantly related genotypes. These results also inform genotyping decisions for future association mapping studies to ensure the identification of a sufficient number of molecular markers to tag all linkage blocks.

scholarly journals Genetic differentiation among Parastichopus regalis populations from Western Mediterranean Sea: potential effects of its fishery and current connectivity.

2015 ◽  
Vol 16 (3) ◽  
pp. 489 ◽  
Author(s):  
C. MAGGI ◽  
M. GONZÁLEZ-WANGÜEMERT
Keyword(s):  
Genetic Diversity ◽  
Genetic Differentiation ◽  
Haplotype Diversity ◽  
Western Mediterranean ◽  
Mediterranean Coast ◽  
Morphological Data ◽  
Coi Gene ◽  
Fixation Index ◽  
Morphological Description ◽  
Western Mediterranean Sea

Parastichopus regalis (Cuvier, 1817) is the most expensive seafood product on the catalonian market (NE Spain), with prices around 130 €/Kg (fresh weight). Despite its ecological and economic importance, biological and genetic information on this sea cucumber species is scarce. We provided the first insight on the genetic structure of P. regalis using sequences of cytochrome oxidase I (COI) and 16S genes, as well as a morphological description of its populations. Individuals were collected in six locations along the Spanish Mediterranean coast, including an area under fishery pressure (Catalonia). We found high haplotype diversity and low nucleotide diversity for both genes, with higher levels of genetic diversity observed on COI gene. Population pairwise fixation index (FST), AMOVA and correspondence analysis (CA) based on COI, revealed significant genetic differentiation among some locations. However, further analysis using nuclear markers (e.g. microsatellites) would be necessary to corroborate these results. Moreover, the genetic and morphological data may indicate fishery effects on the Catalonian population with decrease of the size and weight average and lower genetic diversity compared to locations without fishery pressure. For an appropriate management of this species, we suggest: 1) an accurate assessment of the stocks status along the Spanish coasts; 2) the study of the reproductive cycle of this target species and the establishment of a closed fishery season according to it; 3) the founding of protected areas (i.e. not take zones) to conserve healthy populations and favour the recruitment on the nearby areas.

scholarly journals Assessment of genetic variability among accessions of okra (Abelmoschus esculentus L. Moench)

2021 ◽  
Vol 24 (2) ◽  
pp. 141-147
Author(s):  
Richard Olayiwola ◽  
Rukayat Ayomikun Yusuf ◽  
Oyeboade Adebiyi Oyetunde ◽  
Olufemi Sunday Sosanya ◽  
Omolayo Johnson Ariyo
Keyword(s):  
Genetic Diversity ◽  
Genetic Variability ◽  
Central Africa ◽  
Principal Component ◽  
Breeding Program ◽  
Genetic Base ◽  
Cropping Season ◽  
Principal Component Analyses ◽  
Early Maturing ◽  
West And Central Africa

Abstract Okra yields are low in West and Central Africa and factors including narrow genetic base of available germplasm have been implicated. An assessment of genetic variability among germplasm from various sources and knowledge of trait contributions to these variations is crucial to the success of okra breeding program. Eighteen okra accessions were evaluated during the 2020 cropping season in Nigeria to assess the genotypes for genetic diversity, group the accessions into clusters and identify traits that chiefly accounted for the variations among the genotypes. Data obtained were subjected to analysis of variance (ANOVA), metroglyph and principal component analyses (PCA). ANOVA revealed significant accession mean squares for majority of the measured traits. Metroglyph analysis grouped the accessions into four clusters with members of Cluster IV generally high-yielding, early-maturing and short genotypes. NGB00353 and NGB00356 that were among genotypes with high total index scores were members of Cluster IV. The first four principal components (PCs) accounted for 80% of the total observed variation. PC1 with the highest discriminatory power was loaded with days to budding, internode length, pod yield.plot−1 and the number of pods.plant−1. The variation within and between clusters could be explored in okra breeding program.

scholarly journals Genetic diversity analysis of Dermacentor nuttalli within Inner Mongolia, China

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Zheng Gui ◽  
Lin Wu ◽  
Hao Cai ◽  
Lan Mu ◽  
Jing-Feng Yu ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
16S Rrna ◽  
Genetic Differentiation ◽  
Inner Mongolia ◽  
Haplotype Diversity ◽  
Fixation Index ◽  
Rrna Gene ◽  
Human Beings ◽  
Autonomous Region ◽  
Inner Mongolia Autonomous Region

Abstract Background Ticks (Arthropoda, Ixodida), after mosquitoes, are the second most prevalent vector of infectious diseases. They are responsible for spreading a multitude of pathogens and threatening the health and welfare of animals and human beings. However, given the history of tick-borne pathogen infections in the Inner Mongolia Autonomous Region of China, surprisingly, neither the genetic diversity nor the spatial distribution of haplotypes within ticks has been studied. Methods We characterized the haplotype distribution of Dermacentor nuttalli in four main pastoral areas of the Inner Mongolia Autonomous Region, by sampling 109 individuals (recovered from sheep) in April–August 2019. The 16S rRNA gene, cytochrome c oxidase subunit I (COI), and the internal transcribed spacer 2 region (ITS2) were amplified and sequenced from extracted DNA. Results Twenty-six haplotypes were identified using 16S rRNA sequences, 57 haplotypes were identified with COI sequences, and 75 haplotypes were identified with ITS2 sequences. Among the three genes, total haplotype diversity was greater than 0.7, while total nucleotide diversity was greater than 0.06. Neutrality tests revealed a significantly negative Tajima’s D result, while Fu's Fs was not significantly positive. Fixation index values (FST) indicated that the degree of genetic differentiation among some sampled populations was small, while for others it was moderate. Analysis of molecular variance (AMOVA) revealed that the variation within populations was greater than that among populations. The mismatch analysis of D. nuttalli exhibited double peaks. Conclusion The genetic diversity of D. nuttalli populations in our region can likely adapt to different geographical environments, thereby leading to genetic diversity, and creating genetic differentiation among different populations. However, genetic differentiation is cryptic and does not form a pedigree geographical structure.

scholarly journals Genetic diversity analysis of a Flax (Linum usitatissimum L.) global collection

2020 ◽  
Author(s):  
Ahasanul Hoque ◽  
Jason D. Fiedler ◽  
Mukhlesur Rahman
Keyword(s):  
Genetic Diversity ◽  
Linkage Disequilibrium ◽  
Genetic Differentiation ◽  
Genetic Gain ◽  
Mantel Test ◽  
Breeding Program ◽  
Neighbor Joining ◽  
Breeding Lines ◽  
The North ◽  
Linum Usitatissimum L

Abstract Background A sustainable breeding program requires a minimum level of germplasm diversity to provide varied options for the selection of new breeding lines. To maximize genetic gain of the North Dakota State University (NDSU) flax breeding program, we aimed to increase the genetic diversity of its parental stocks by incorporating diverse genotypes. For this purpose, we analyzed the genetic diversity, linkage disequilibrium, and population sub-structure of 350 globally-distributed flax genotypes with 6,200 SNP markersResults All the genotypes tested clustered into seven sub-populations (P1 to P7) based on the admixture model and the output of neighbor-joining (NJ) tree analysis and principal coordinate analysis were in line with that of structure analysis. The largest sub-population separation arose from a cluster of NDSU/American genotypes with Turkish and Asian genotypes. All sub-populations showed moderate genetic diversity (average H = 0.22 and I = 0.34). The pairwise F st comparison revealed a great degree of divergence ( F st > 0.25) between most of the combinations. A whole collection mantel test showed significant positive correlation (r = 0.30 and p < 0.01) between genetic and geographic distances, whereas it was non-significant for all sub-populations except P4 and P5 (r= 0.251, 0.349 respectively and p < 0.05). In the entire collection, the mean linkage disequilibrium was 0.03 and it decayed to its half maximum within < 21 kb distance.Conclusions To maximize genetic gain, hybridization between NDSU stock (P5) and Asian individuals (P6) are potentially the best option as genetic differentiation between them is highest ( F st > 0.50). In contrast, low genetic differentiation between P5 and P2 may enhance the accumulation of favorable alleles for oil and fiber upon crossing to develop dual purpose varieties. As each sub-population consists of many genotypes, a Neighbor-Joining tree assists to identify distantly related genotypes. These results also inform genotyping decisions for future association mapping studies to ensure the identification of a sufficient number of molecular markers to tag all linkage blocks.

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