adaptive selection
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2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Davide Pradovera ◽  
Fabio Nobile

AbstractIn the field of model order reduction for frequency response problems, the minimal rational interpolation (MRI) method has been shown to be quite effective. However, in some cases, numerical instabilities may arise when applying MRI to build a surrogate model over a large frequency range, spanning several orders of magnitude. We propose a strategy to overcome these instabilities, replacing an unstable global MRI surrogate with a union of stable local rational models. The partitioning of the frequency range into local frequency sub-ranges is performed automatically and adaptively, and is complemented by a (greedy) adaptive selection of the sampled frequencies over each sub-range. We verify the effectiveness of our proposed method with two numerical examples.


2021 ◽  
Author(s):  
Xuan Chen ◽  
Hong-Yan Guo ◽  
Qing-Ying Zhang ◽  
Lu Wang ◽  
Rong Guo ◽  
...  

Abstract Background: Cannabis is an important industrial crop, whose bast fiber, seed, flowers and leaves are widely used by humans,especially cannabinoids extracted from plants as medicine is a hot spot in recent years. China is one of the origins of cannabis, where it has been cultivated and utilized for more than 6000 years, with the largest planting area of industrial hemp at present. China is rich in cannabis germplasm resources covering different latitudes (23 to 51°N) and is one of the few countries with wild cannabis resources. However, the genetic structure of Chinese cannabis populations and the adaptive selection of important traits remain unclear.Results: We identified the main morphological and physiological characteristics of wild cannabis and defined the genetic structure and relationships among wild and cultivated Chinese cannabis accessions and foreign representatives. This suggested that wild resources in Xinjiang have played an important role in the process of cannabis domestication. Adaptive selection analysis revealed that cultivated cannabis has undergone selective evolution or adaptation in flowering, growth and stress tolerance, and many functional genes were identified. Flowering characteristics analysis implied that wild cannabis is native to high latitudes and possesses the typical characteristic of early flowering, while cultivated cannabis has undergone a process of adaptive evolution to adjust to natural photoperiod conditions in different latitudes through regulation of FT-like expression.Conclusion: This study clarifies the genetic structure of Chinese cannabis and provides insight into adaptive selection and breeding in cannabis.


2021 ◽  
Vol 288 (1964) ◽  
Author(s):  
Tom M. Allison ◽  
Arunas L. Radzvilavicius ◽  
Damian K. Dowling

Uniparental inheritance (UPI) of mitochondria predominates over biparental inheritance (BPI) in most eukaryotes. However, examples of BPI of mitochondria, or paternal leakage, are becoming increasingly prevalent. Most reported cases of BPI occur in hybrids of distantly related sub-populations. It is thought that BPI in these cases is maladaptive; caused by a failure of female or zygotic autophagy machinery to recognize divergent male-mitochondrial DNA ‘tags’. Yet recent theory has put forward examples in which BPI can evolve under adaptive selection, and empirical studies across numerous metazoan taxa have demonstrated outbreeding depression in hybrids attributable to disruption of population-specific mitochondrial and nuclear genotypes (mitonuclear mismatch). Based on these developments, we hypothesize that BPI may be favoured by selection in hybridizing populations when fitness is shaped by mitonuclear interactions. We test this idea using a deterministic, simulation-based population genetic model and demonstrate that BPI is favoured over strict UPI under moderate levels of gene flow typical of hybridizing populations. Our model suggests that BPI may be stable, rather than a transient phenomenon, in hybridizing populations.


Author(s):  
N. M. Gutieva

A genetic collection of the genus Pelargonium L’Herit. ex Ait., with 40 % stock represented by Pelargoniumgrandiflorum hybridium hort., is originated at the Federal Subtropical Research Centre of the Russian Academy of Sciences. The main collection varieties, including Aristo, Elegance, Candy Flowers, Hazel and Bermuda, are foreign selections attaining their best qualities under optimal soil and climatic conditions. Cultivation in humid subtropics disturbs their growth and development, at the same time as deteriorating their productivity and ornamental value. The research aimed to study the hybrid stock towards the selection of hardiest, most ornamental and long-flowering forms corresponding to a specified variety model. The variety model developed for Russian subtropic agroclimate incorporated a main set of economically valuable and adaptively significant traits. Over 30 varietal crossbreedings have been conducted to select for promising recombinants and hybrid families. A high variability of phenotypic ornamental traits has been observed in the crosses offspring. We identified 15 promising hybrids from the total morphological trait combination. Adaptive selection against stress factors has been proved effective. The most successful combinations were Hazel Ripple x Yashma, Hazel Cherry x Rozovyy Briz and A. Darling x Rozovyy Briz. A subset of elite forms (Kd-15-43, Kr-16-28 and Kc-18-22) maximising the number of significant breeding traits have further been selected towards a higher total score (≥95). K.j.-17-15, Kq-18-04 and K.ya-16-03 were recognised promising for large-flowered form selection. The Yagodnyy Tsvet variety, Kv-18-01 and K.d.-18-09 hybrids (over 35 inflorescences) have been identified as sources for high flower production. K.p-17-65, Kr-16-28 and Kc-18-22 were the hybrids with flowering period exceeding 100 days. All crosses were based on Hazel as a maternal form sourcing the trait.


Genomics ◽  
2021 ◽  
Vol 113 (6) ◽  
pp. 3599-3609
Author(s):  
Yan Ren ◽  
Callum MacPhillamy ◽  
Thu-Hien To ◽  
Timothy P.L. Smith ◽  
John L. Williams ◽  
...  

2021 ◽  
Vol 12 ◽  
Author(s):  
Andreas Maurer ◽  
Klaus Pillen

Nowadays, genetic diversity more than ever represents a key driver of adaptation to climate challenges like drought, heat, and salinity. Therefore, there is a need to replenish the limited elite gene pools with favorable exotic alleles from the wild progenitors of our crops. Nested association mapping (NAM) populations represent one step toward exotic allele evaluation and enrichment of the elite gene pool. We investigated an adaptive selection strategy in the wild barley NAM population HEB-25 based on temporal genomic data by studying the fate of 214,979 SNP loci initially heterozygous in individual BC1S3 lines after five cycles of selfing and field propagation. We identified several loci exposed to adaptive selection in HEB-25. In total, 48.7% (104,725 SNPs) of initially heterozygous SNP calls in HEB-25 were fixed in BC1S3:8 generation, either toward the wild allele (19.9%) or the cultivated allele (28.8%). Most fixed SNP loci turned out to represent gene loci involved in domestication and flowering time as well as plant height, for example, btr1/btr2, thresh-1, Ppd-H1, and sdw1. Interestingly, also unknown loci were found where the exotic allele was fixed, hinting at potentially useful exotic alleles for plant breeding.


Author(s):  
Jianming Zhang ◽  
Yang Liu ◽  
Hehua Liu ◽  
Jin Wang ◽  
Yudong Zhang

Author(s):  
Xiangtian Xue ◽  
Changping Du ◽  
Yang Chen ◽  
Shijie Wang ◽  
Wenxue Yu ◽  
...  

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