scholarly journals AlphaMate: a program for optimising selection, maintenance of diversity, and mate allocation in breeding programs

2018 ◽  
Author(s):  
Gregor Gorjanc ◽  
John M. Hickey

ABSTRACTSummaryAlphaMate is a flexible program that optimises selection, maintenance of genetic diversity, and mate allocation in breeding programs. It can be used in animal and cross- and self-pollinating plant populations. These populations can be subject to selective breeding or conservation management. The problem is formulated as a multi-objective optimisation of a valid mating plan that is solved with an evolutionary algorithm. A valid mating plan is defined by a combination of mating constraints (the number of matings, the maximal number of parents, the minimal/equal/maximal number of contributions per parent, or allowance for selfing) that are gender specific or generic. The optimisation can maximize genetic gain, minimize group coancestry, minimize inbreeding of individual matings, or maximize genetic gain for a given increase in group coancestry or inbreeding. Users provide a list of candidate individuals with associated gender and selection criteria information (if applicable) and coancestry matrix. Selection criteria and coancestry matrix can be based on pedigree or genome-wide markers. Additional individual or mating specific information can be included to enrich optimisation objectives. An example of rapid recurrent genomic selection in wheat demonstrates how AlphaMate can double the efficiency of converting genetic diversity into genetic gain compared to truncation selection. Another example demonstrates the use of genome editing to expand the gain-diversity frontier.AvailabilityExecutable versions of AlphaMate for Windows, Mac, and Linux platforms are available at http://www.alpha-genes.roslin.ed.ac.uk/[email protected]

Aquaculture ◽  
2017 ◽  
Vol 472 ◽  
pp. 30-37 ◽  
Author(s):  
M. Saura ◽  
B. Villanueva ◽  
J. Fernández ◽  
M.A. Toro

2021 ◽  
Author(s):  
Peter Civan ◽  
Renaud Rincent ◽  
Alice Danguy-Des-Deserts ◽  
Jean-Michel Elsen ◽  
Sophie Bouchet

AbstractThe breeding efforts of the twentieth century contributed to large increases in yield but selection may have increased vulnerability to environmental perturbations. In that context, there is a growing demand for methodology to re-introduce useful variation into cultivated germplasm. Such efforts can focus on the introduction of specific traits monitored through diagnostic molecular markers identified by QTL/association mapping or selection signature screening. A combined approach is to increase the global diversity of a crop without targeting any particular trait.A considerable portion of the genetic diversity is conserved in genebanks. However, benefits of genetic resources (GRs) in terms of favorable alleles have to be weighed against unfavorable traits being introduced along. In order to facilitate utilization of GR, core collections are being identified and progressively characterized at the phenotypic and genomic levels. High-throughput genotyping and sequencing technologies allow to build prediction models that can estimate the genetic value of an entire genotyped collection. In a pre-breeding program, predictions can accelerate recurrent selection using rapid cycles in greenhouses by skipping some phenotyping steps. In a breeding program, reduced phenotyping characterization allows to increase the number of tested parents and crosses (and global genetic variance) for a fixed budget. Finally, the whole cross design can be optimized using progeny variance predictions to maximize short-term genetic gain or long-term genetic gain by constraining a minimum level of diversity in the germplasm. There is also a potential to further increase the accuracy of genomic predictions by taking into account genotype by environment interactions, integrating additional layers of omics and environmental information.Here, we aim to review some relevant concepts in population genomics together with recent advances in quantitative genetics in order to discuss how the combination of both disciplines can facilitate the use of genetic diversity in plant (pre) breeding programs.


2019 ◽  
Author(s):  
Antoine Allier ◽  
Christina Lehermeier ◽  
Alain Charcosset ◽  
Laurence Moreau ◽  
Simon Teyssèdre

AbstractThe implementation of genomic selection in recurrent breeding programs raised several concerns, especially that a higher inbreeding rate could compromise the long term genetic gain. An optimized mating strategy that maximizes the performance in progeny and maintains diversity for long term genetic gain on current and yet unknown future targets is essential. The optimal cross selection approach aims at identifying the optimal set of crosses maximizing the expected genetic value in the progeny under a constraint on diversity in the progeny. Usually, optimal cross selection does not account for within family selection, i.e. the fact that only a selected fraction of each family serves as candidate parents of the next generation. In this study, we consider within family variance accounting for linkage disequilibrium between quantitative trait loci to predict the expected mean performance and the expected genetic diversity in the selected progeny of a set of crosses. These predictions rely on the method called usefulness criterion parental contribution (UCPC). We compared UCPC based optimal cross selection and optimal cross selection in a long term simulated recurrent genomic selection breeding program considering overlapping generations. UCPC based optimal cross selection proved to be more efficient to convert the genetic diversity into short and long term genetic gains than optimal cross selection. We also showed that using the UCPC based optimal cross selection, the long term genetic gain can be increased with only limited reduction of the short term commercial genetic gain.


Heredity ◽  
2021 ◽  
Author(s):  
Francis Denisse McLean-Rodríguez ◽  
Denise Elston Costich ◽  
Tania Carolina Camacho-Villa ◽  
Mario Enrico Pè ◽  
Matteo Dell’Acqua

AbstractGenomics-based, longitudinal comparisons between ex situ and in situ agrobiodiversity conservation strategies can contribute to a better understanding of their underlying effects. However, landrace designations, ambiguous common names, and gaps in sampling information complicate the identification of matching ex situ and in situ seed lots. Here we report a 50-year longitudinal comparison of the genetic diversity of a set of 13 accessions from the state of Morelos, Mexico, conserved ex situ since 1967 and retrieved in situ from the same donor families in 2017. We interviewed farmer families who donated in situ landraces to understand their germplasm selection criteria. Samples were genotyped by sequencing, producing 74,739 SNPs. Comparing the two sample groups, we show that ex situ and in situ genome-wide diversity was similar. In situ samples had 3.1% fewer SNPs and lower pairwise genetic distances (Fst 0.008–0.113) than ex situ samples (Fst 0.031–0.128), but displayed the same heterozygosity. Despite genome-wide similarities across samples, we could identify several loci under selection when comparing in situ and ex situ seed lots, suggesting ongoing evolution in farmer fields. Eight loci in chromosomes 3, 5, 6, and 10 showed evidence of selection in situ that could be related with farmers’ selection criteria surveyed with focus groups and interviews at the sampling site in 2017, including wider kernels and larger ear size. Our results have implications for ex situ collection resampling strategies and the in situ conservation of threatened landraces.


2021 ◽  
Author(s):  
Heidi Anderson ◽  
Stephen Davison ◽  
Katie M. Lytle ◽  
Leena Honkanen ◽  
Jamie Freyer ◽  
...  

In the largest DNA-based study of domestic cat to date, 11,036 individuals (10,419 pedigreed cats from 91 breeds and breed types and 617 non-pedigreed cats) were genotyped via commercial panel testing, elucidating the distribution and frequency of known genetic variants associated with blood type, disease and physical traits across cat breeds. Blood group determining variants, which are relevant clinically and in cat breeding, were genotyped to assess the across breed distribution of blood types A, B and AB. Extensive panel testing identified 13 disease-associated variants in 48 breeds or breed types for which the variant had not previously been observed, strengthening the argument for panel testing across populations. The study also indicates that multiple breed clubs have effectively used DNA testing to reduce disease-associated genetic variants within certain pedigreed cat populations. Appearance-associated genetic variation in all cats is also discussed. Additionally, we combined genotypic data with phenotype information and clinical documentation, actively conducted owner and veterinarian interviews, and recruited cats for clinical examination to investigate the causality of a number of tested variants across different breed backgrounds. Lastly, genome-wide informative SNP heterozygosity levels were calculated to obtain a comparable measure of the genetic diversity in different cat breeds. This study represents the first comprehensive exploration of informative Mendelian variants in felines by screening over 10,000 domestic cats. The results qualitatively contribute to the understanding of feline variant heritage and genetic diversity and demonstrate the clinical utility and importance of such information in supporting breeding programs and the research community. The work also highlights the crucial commitment of pedigreed cat breeders and registries in supporting the establishment of large genomic databases that when combined with phenotype information can advance scientific understanding and provide insights that can be applied to improve the health and welfare of cats.


2019 ◽  
Author(s):  
Mingshu Cao ◽  
Marty Faville ◽  
Jeanne Jacobs ◽  
Marcelo Carena

AbstractChloroplast and mitochondrial genomes provide unique information in studying plant populations because cytoplasmic genes exhibit a different mode of inheritance and a different rate of gene mutation compared to nuclear genes. Despite this, cytoplasmic genomic contributions to plant population performance are largely unexplored because few methods are available to characterize and evaluate cytoplasmic genome-wide variations. Here we have developed cytoplasmic markers based on genotyping-by-sequencing (GBS), which enable us to characterize thousands of samples, to survey gene variants across cytoplasmic genomes, and to monitor within-population variations of chloroplast or mitochondrial origin. Using these cytoplasmic genome-wide markers we have found that within-population differentiations are evident in ryegrass (Lolium perenne), beyond the explanation of nuclear markers. Moreover, chloroplast and mitochondrial variations exhibit different patterns, with mitochondrial markers more readily reflecting the maternal origins. Application of GBS-based cytoplasmic markers should facilitate quantifying the contribution of cytoplasmic inheritance to plant performance through selective breeding or under natural selection pressure.


Author(s):  
Mariangela Arca ◽  
Brigitte Gouesnard ◽  
Tristan Mary-Huard ◽  
Marie-Christine Le Paslier ◽  
Cyril Bauland ◽  
...  

ABSTRACTMaize landraces preserved in genebanks have a large genetic diversity that is still poorly characterized and underexploited in modern breeding programs. Here, we genotyped DNA pools from 156 American and European landraces with a 50K SNP Illumina array to study the effect of both human selection and environmental adaptation on the genome-wide diversity of maize landraces. Genomic diversity of landraces varied strongly in different parts of the genome and with geographic origin. We detected selective footprints between landraces of different geographic origin in genes involved in the starch pathway (Su1, Waxy1), flowering time (Zcn8, Vgt3, ZmCCT9) and tolerance to abiotic and biotic stress (ZmASR, NAC and dkg genes). Landrace diversity was compared to that of (i) 327 inbred lines representing American and European diversity (“CK lines) and (ii) 103 new lines derived directly from landraces (“DH-SSD lines”). We observed limited diversity loss or selective sweep between landraces and CK lines, except in peri-centromeric regions. However, analysis of modified Roger’s distance between landraces and the CK lines showed that most landraces were not closely related to CK lines. Assignment of CK lines to landraces using supervised analysis showed that only a few landraces, such as Reid’s Yellow Dent, Lancaster Surecrop and Lacaune, strongly contributed to modern European and American breeding pools. Haplotype diversity of CK lines was more enriched by DH-SSD lines that derived from the landraces with no related lines and the lowest contribution to CK lines. Our approach opens an avenue for the identification of promising landraces for pre-breeding.SIGNIFICANCE STATEMENTSMaize landraces are a valuable source of genetic diversity for addressing the challenges of climate change and the requirements of low input agriculture as they have been long selected to be well adapted to local agro-climatic conditions and human uses. However, they are underutilized in modern breeding programs because they are poorly characterized, genetically heterogeneous and exhibit poor agronomic performance compared to elite hybrid material. In this study, we developed a high-throughput approach to identify landraces that could potentially enlarge the genetic diversity of modern breeding pools. We genotyped DNA pools from landraces using 50K array technology, which is widely used by breeders to characterize the genetic diversity of inbred lines. To identify landraces that could enrich the modern maize germplasm, we estimated their contribution to inbred lines using supervised analysis and a new measurement of genetic distance.


2019 ◽  
Vol 51 (1) ◽  
Author(s):  
Jonathan D’Ambrosio ◽  
Florence Phocas ◽  
Pierrick Haffray ◽  
Anastasia Bestin ◽  
Sophie Brard-Fudulea ◽  
...  

2021 ◽  
Author(s):  
Yongjun Li ◽  
Sukhjiwan Kaur ◽  
Luke W. Pembleton ◽  
Hossein Valipour-Kahrood ◽  
Garry M. Rosewarne ◽  
...  

Abstract Using a stochastic computer simulation, we investigated the benefit of optimization strategies in the context of genomic selection (GS) for pulse breeding programs. We simulated GS for moderately complex to highly complex traits such as disease resistance, grain weight and grain yield in multiple environments with a high level of genotype-by-environment interaction for grain yield. GS led to higher genetic gain per unit of time and higher genetic diversity loss than phenotypic selection by shortening the breeding cycle time. The genetic gain obtained from selecting the segregating parents early in the breeding cycle (at F1 or F2 stages) was substantially higher than selecting at later stages even though prediction accuracy was moderate. Increasing the number of F1 intercross (F1i) families and keeping the total number of progeny of F1i families constant, we observed a decrease in genetic gain and increase in genetic diversity. Whereas increasing the number of progeny per F1i family while keeping a constant number of F1i families increased rate of genetic gain and had higher genetic diversity loss per unit of time. Adding 50 F2 family phenotypes to the training population increased the accuracy of GEBVs and genetic gain per year and decreased the rate of genetic diversity loss. Genetic diversity could be preserved by applying a strategy that restricted both the percentage of alleles fixed and the average relationship of the group of selected parents to preserve long-term genetic improvement in the pulse breeding program.


2021 ◽  
Vol 31 ◽  
pp. 00009
Author(s):  
Markhabat Kairova ◽  
Gulnara Sitpayeva

The rarest species of relict ironwood C. caucasica Willd. is naturally occurred on the Ile-Alatau Mountains but very little is known about genetic diversity and distribution and size of its populations in Kazakhstan. In during the sampling expedition were found two additional plant populations in Dzungarian and Kyrgyz Alatau Ranges. The objective of this work was targeted towards sequencing ITS region of C. caucasica and compare the obtained nucleotide sequence with available data on NCBI GeneBank for confident species identification. The identity of C. caucasica sequence and available C. australis and C. bungeana sequences was 93.87% and less. It could be associated with absence sequences producing significant alignments with the studied ironwood sequence and important deposited sequences of GenBank lacking Latin binominals is from environmental samples. Clarifying taxonomical status species and subspecies is difficult by morphological data and molecular markers should be used to correct identifying an endangered species of C. caucasica growing in the east-southern and the south regions of Kazakhstan and providing direction to the conservation management of the plant.


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