scholarly journals Comparing genomic-based estimates of relatedness for use in pedigree-based conservation management

2021 ◽  
Author(s):  
Samantha S Hauser ◽  
Stephanie J Galla ◽  
Tammy E Steeves ◽  
Emily K Latch

Researchers have long debated which genomic estimator of relatedness best captures the degree of relationship between two individuals. In the genomics era, this debate continues, with relatedness estimates being sensitive to the method used to generate genomic markers (e.g., reduced-representation sequencing, whole genome resequencing), marker quality, and levels of diversity in sampled individuals. Here, we compare six commonly used relatedness estimators (kinship genetic distance (KGD), Wang Maximum Likelihood (TrioML), Queller and Goodnight (Rxy), KING-robust, RAB, allele-sharing coancestry) across five species bred in captivity - including three birds and two mammals with varying degrees of reliable pedigree data, using reduced-representation and whole genome resequencing data. Relatedness estimates varied widely across estimators, sequencing method, and species, yet the most consistent results with known pedigree data were found using KING-robust and to a lesser extent KGD. The allele-sharing estimator was sensitive to missing data and inbreeding, attributes that make this estimator ill-suited for use in captive breeding programs. Our combined results indicate there is not a single genomic based estimator that is ideal across different species and data types. To enable researchers to evaluate the most appropriate relatedness estimator for each new data set, we provide a structured workflow that is broadly applicable to conservation breeding programs, particularly where genomic estimates of relatedness can complement and complete poorly pedigreed populations. Given a growing interest in wild pedigrees, our results and workflow are also applicable to in situ wildlife management.

Author(s):  
Daria Martchenko ◽  
Aaron Shafer

Genomic approaches to the study of population demography rely on accurate SNP calling and by-proxy the site frequency spectrum (SFS). Two main questions for the design of such studies remain poorly investigated: do reduced genomic sequencing summary statistics reflect that of whole genome, and how do sequencing strategies and derived summary statistics impact demographic inferences? To address those questions, we applied the ddRAD sequencing approach to 254 individuals and whole genome resequencing approach to 35 mountain goat (Oreamnos americanus) individuals across the species range with a known demographic history. We identified SNPs with 5 different variant callers and used ANGSD to estimate the genotype likelihoods (GLs). We tested combinations of SNP filtering by linkage disequilibrium (LD), minor allele frequency (MAF) and the genomic region. We compared the resulting suite of summary statistics reflective of the SFS and quantified the relationship to demographic inferences by estimating the contemporary effective population size (Ne), isolation-by-distance and population structure, FST, and explicit modelling of the demographic history with δaδi. Filtering had a larger effect than sequencing strategy, with the former strongly influencing summary statistics. Estimates of contemporary Ne and isolation-by-distance patterns were largely robust to the choice of sequencing, pipeline, and filtering. Despite the high variance in summary statistics, whole genome and reduced representation approaches were overall similar in supporting a glacial induced vicariance and low Ne in mountain goats. We discuss why whole genome resequencing data is preferable, and reiterate support the use of GLs, in part because it limits user-determined filters.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Luciano Calderón ◽  
Nuria Mauri ◽  
Claudio Muñoz ◽  
Pablo Carbonell-Bejerano ◽  
Laura Bree ◽  
...  

AbstractGrapevine cultivars are clonally propagated to preserve their varietal attributes. However, genetic variations accumulate due to the occurrence of somatic mutations. This process is anthropically influenced through plant transportation, clonal propagation and selection. Malbec is a cultivar that is well-appreciated for the elaboration of red wine. It originated in Southwestern France and was introduced in Argentina during the 1850s. In order to study the clonal genetic diversity of Malbec grapevines, we generated whole-genome resequencing data for four accessions with different clonal propagation records. A stringent variant calling procedure was established to identify reliable polymorphisms among the analyzed accessions. The latter procedure retrieved 941 single nucleotide variants (SNVs). A reduced set of the detected SNVs was corroborated through Sanger sequencing, and employed to custom-design a genotyping experiment. We successfully genotyped 214 Malbec accessions using 41 SNVs, and identified 14 genotypes that clustered in two genetically divergent clonal lineages. These lineages were associated with the time span of clonal propagation of the analyzed accessions in Argentina and Europe. Our results show the usefulness of this approach for the study of the scarce intra-cultivar genetic diversity in grapevines. We also provide evidence on how human actions might have driven the accumulation of different somatic mutations, ultimately shaping the Malbec genetic diversity pattern.


BMC Genomics ◽  
2011 ◽  
Vol 12 (1) ◽  
Author(s):  
Paul Stothard ◽  
Jung-Woo Choi ◽  
Urmila Basu ◽  
Jennifer M Sumner-Thomson ◽  
Yan Meng ◽  
...  

Life ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 959
Author(s):  
Alexander Igoshin ◽  
Nikolay Yudin ◽  
Ruslan Aitnazarov ◽  
Andrey A. Yurchenko ◽  
Denis M. Larkin

Despite the economic importance of creating cold resilient cattle breeds, our knowledge of the genetic basis of adaptation to cold environments in cattle is still scarce compared to information on other economically important traits. Herein, using whole-genome resequencing of animals showing contrasting phenotypes on temperature maintenance under acute cold stress combined with the existing SNP (single nucleotide polymorphism) functional annotations, we report chromosomal regions and candidate SNPs controlling body temperature in the Siberian cattle populations. The SNP ranking procedure based on regional FST calculations, functional annotations, and the allele frequency difference between cold-tolerant and cold-sensitive groups of animals pointed to multiple candidate genes. Among these, GRIA4, COX17, MAATS1, UPK1B, IFNGR1, DDX23, PPT1, THBS1, CCL5, ATF1, PLA1A, PRKAG1, and NR1I2 were previously related to thermal adaptations in cattle. Other genes, for example KMT2D and SNRPA1, are known to be related to thermogenesis in mice and cold adaptation in common carp, respectively. This work could be useful for cattle breeding strategies in countries with harsh climates, including the Russian Federation.


2021 ◽  
Author(s):  
Yifei Jiang ◽  
Huaiyong Luo ◽  
Bolun Yu ◽  
Yingbin Ding ◽  
Yanping Kang ◽  
...  

Abstract Cultivated peanut (Arachis hypogaea L.) is rich in edible oil and protein, which is widely planted around the world as an oil and cash crop. However, aflatoxin contamination seriously affects the quality safety of peanut, hindering the development of peanut industry and threatening consumers’ health. Breeding peanut varieties with resistance to Aspergillus flavus infection is important for control the aflatoxin contamination, and understanding of the genetic basis of resistance is vital to its genetic enhancement. In this study, we report the QTL mapping of resistance to A. flavus infection of a well-known resistant variety J11. A recombination inbred line (RIL) population was constructed by crossing a susceptible variety Zhonghua 16 and J11. Through whole-genome resequencing, a genetic linkage map was constructed with 2,802 recombination bins and an average inter-bin distance of 0.58 cM. Combined with phenotypic data of infection index in four consecutive years, six novel resistant QTLs were identified and they explained 5.03-10.87% phenotypic variances. The favorable alleles of five QTLs were from J11 while that of one QTL were from Zhonghua 16. The pyramiding of these favorable alleles significantly improved the resistance to A. flavus infection. These results could contribute greatly to understanding of genetic basis of A. flavus resistance and could be meaningful in further resistance improvement in peanut.


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