Environmental and Genetic Constraints on Adaptive Population Differentiation in Anthoxanthum odoratum

Evolution ◽  
1992 ◽  
Vol 46 (2) ◽  
pp. 341 ◽  
Author(s):  
Gerrit A. J. Platenkamp ◽  
Ruth G. Shaw
Keyword(s):  
Population Differentiation ◽  
Genetic Constraints ◽  
Anthoxanthum Odoratum

scholarly journals Temperature and Rainfall Are Separate Agents of Selection Shaping Population Differentiation in a Forest Tree

Forests ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 1145
Author(s):  
João Costa e Silva ◽  
Brad Potts ◽  
Peter A. Harrison ◽  
Tanya Bailey
Keyword(s):  
Natural Selection ◽  
Population Differentiation ◽  
Natural Populations ◽  
Population Level ◽  
Direct Consequence ◽  
Arid Environment ◽  
Forest Tree ◽  
Machine Learning Algorithms ◽  
Multiple Sources ◽  
Genetic Constraints

Research highlights: We present evidence indicating that covariation of functional traits among populations of a forest tree is not due to genetic constraints, but rather selective covariance arising from local adaptation to different facets of the climate, namely rainfall and temperature. Background and Aims: Traits frequently covary among natural populations. Such covariation can be caused by pleiotropy and/or linkage disequilibrium, but also may arise when the traits are genetically independent as a direct consequence of natural selection, drift, mutation and/or gene flow. Of particular interest are cases of selective covariance, where natural selection directly generates among-population covariance in a set of genetically independent traits. We here studied the causes of population-level covariation in two key traits in the Australian tree Eucalyptus pauciflora. Materials and Methods: We studied covariation in seedling lignotuber size and vegetative juvenility using 37 populations sampled from throughout the geographic and ecological ranges of E. pauciflora on the island of Tasmania. We integrated evidence from multiple sources: (i) comparison of patterns of trait covariation within and among populations; (ii) climate-trait modelling using machine-learning algorithms; and (iii) selection analysis linking trait variation to field growth in an arid environment. Results: We showed strong covariation among populations compared with the weak genetic correlation within populations for the focal traits. Population differentiation in these genetically independent traits was correlated with different home-site climate variables (lignotuber size with temperature; vegetative juvenility with rainfall), which spatially covaried. The role of selection in shaping the population differentiation in lignotuber size was supported by its relationship with fitness measured in the field. Conclusions: Our study highlights the multi-trait nature of adaptation likely to occur as tree species respond to spatial and temporal changes in climate.

Understanding genetic diversity, structure and population differentiation in selected wild species and cultivated Indian and exotic rose varieties based on microsatellite allele frequencies

2019 ◽  
Vol 79 (3) ◽  
Author(s):  
Aparna . Veluru ◽  
Kanwar P. Singh ◽  
Namita . . ◽  
Sapna . Panwar ◽  
Gayacharan . . ◽  
...  
Keyword(s):  
Wild Species ◽  
Population Differentiation ◽  
Ornamental Plants ◽  
Primary Source ◽  
Mean Value ◽  
Rosa Hybrida ◽  
Population Subdivision ◽  
Nutraceutical Compounds ◽  
Ssr Loci ◽  
Admixture Population

Roses are the most important commercial ornamental plants grown for flowers, perfumery and nutraceutical compounds. Commercially cultivated roses (Rosa × hybrida L.) are complex interspecific hybrids probably derived from 8-10 wild species among the large diversity of 130-200 species in genus Rosa. Wild germplasm is a primary source of variability and plays a major role in improving existing varieties by broadening their genetic base. In the present investigation, we have utilized the previously identified SSR primers for studying the diversity among 148 selected rose genotypes, including wild species and cultivated varieties of Indian and exotic origin. A total of 88 alleles was scored using 30 polymorphic loci; they produced average 2.9±1 alleles per locus. Polymorphism information content (PIC) values for different SSR loci ranged from 0.08 to 0.8 with a mean value of 0.5±0.2. The neighbor-joining tree generated based on Nei’s (1978) genetic distance values grouped the population into three major clusters. Cluster-I and II consists of all modern rose cultivars (Rosa × hybrida L.) originated from India and cluster-III consists of all exotic cultivars, wild species and a few cultivars from India. STRUCTURE analysis based on microsatellite allelic data, partitioned the total rose genotypes into four different sub-populations with some individual genotypes having genomic admixture. Population subdivision estimates, FST between different subpopulations ranged from 0.01-0.15 indicates low to moderate level of divergence existing among the rose cultivars and germplasm. Population differentiation in rose cultivars and wild species corresponds to their geographical origin and lineages. Analysis of molecular variance (AMOVA) results revealed that 83.12 % of the variance was accounted for by within sub-groups followed by significant levels of variation among the populations (10.42%) and least variance (6.46%) was noticed among individuals within groups.

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