scholarly journals Long range movements by individuals as a vehicle for range expansion in Calopteryx splendens (Odonata: Zygoptera)

2007 ◽  
Vol 104 (2) ◽  
pp. 195-198 ◽  
Author(s):  
Louise WARD ◽  
Peter MILL
2020 ◽  
Vol 117 (14) ◽  
pp. 7584-7593 ◽  
Author(s):  
Jayson Paulose ◽  
Oskar Hallatschek

Range expansions lead to distinctive patterns of genetic variation in populations, even in the absence of selection. These patterns and their genetic consequences have been well studied for populations advancing through successive short-ranged migration events. However, most populations harbor some degree of long-range dispersal, experiencing rare yet consequential migration events over arbitrarily long distances. Although dispersal is known to strongly affect spatial genetic structure during range expansions, the resulting patterns and their impact on neutral diversity remain poorly understood. Here, we systematically study the consequences of long-range dispersal on patterns of neutral variation during range expansion in a class of dispersal models which spans the extremes of local (effectively short-ranged) and global (effectively well-mixed) migration. We find that sufficiently long-ranged dispersal leaves behind a mosaic of monoallelic patches, whose number and size are highly sensitive to the distribution of dispersal distances. We develop a coarse-grained model which connects statistical features of these spatial patterns to the evolution of neutral diversity during the range expansion. We show that growth mechanisms that appear qualitatively similar can engender vastly different outcomes for diversity: Depending on the tail of the dispersal distance distribution, diversity can be either preserved (i.e., many variants survive) or lost (i.e., one variant dominates) at long times. Our results highlight the impact of spatial and migratory structure on genetic variation during processes as varied as range expansions, species invasions, epidemics, and the spread of beneficial mutations in established populations.


2019 ◽  
Author(s):  
Andrea Ariani ◽  
Paul Gepts

AbstractLandscape genomics integrates population genetics with landscape ecology, allowing the identification of putative molecular determinants involved in environmental adaptation across the natural geographic and ecological range of populations. Wild Phaseolus vulgaris, the progenitor of common bean (P. vulgaris), has a remarkably extended distribution over 10,000 km from northern Mexico to northwestern Argentina. Earlier research has shown that this distribution represents a range expansion from Mesoamerica to the southern Andes through several discrete migration events and that the species colonized areas with different temperature and rainfall compared to its core area of origin. Thus, this species provides an opportunity to examine to what extent adaptation of a species can be broadened or, conversely, ecological or geographical distribution can be limited by inherent adaptedness. In the current study, we applied a landscape genomics approach to a collection of 246 wild common bean accessions representative of its broad geographical and climatic distribution and genotyped for ∼20K SNPs. We applied two different but complementary approaches for identifying loci putatively involved in environmental adaptation: i) an outlier-detection method that identifies loci showing strong differentiation between sub-populations; ii) an association method based on the identification of loci associated with bio-climatic variables. This integrated approach allowed the identification of several genes showing signature of selection across the different natural sub-populations of this species, as well as genes associated with specific bio-climatic variables related to temperature and precipitation. The current study demonstrates the feasibility of landscape genomics approach for a preliminary identification of specific populations and novel candidate genes involved in environmental adaptation in P. vulgaris. As a resource for broadening the genetic diversity of the domesticated gene pool of this species, the genes identified constitute potential molecular markers and introgression targets for the breeding improvement of domesticated common bean.Author SummaryThe ancestral form of common bean has an unusually large distribution in the Americas, extending over 10,000 km from ∼35° N. Lat. to ∼35° S. Lat. This wide distribution results from discrete long-range dissemination events to the Andes region from the original environments in Mesoamerica. It also suggests adaptation to new environments that are distinct from those encountered in Mesoamerica. In this research, we identified genes that may be involved in adaptation to climate variables in these new environments using two methods. A first method – outlier detection – was used to identify genome regions that differentiated the wild bean groups in the Andes resulting from discrete dissemination events among themselves and the different groups in Mesoamerica. The second method – genome-wide association – was used to identify candidate genome regions correlated with these same variables across the entire distribution from Mesoamerica to the southern Andes. The two methods identified two sets of candidate genes, several of which were related to the water status of plants, and illustrate how the genetic architecture of adaptation following long-range dissemination. This study provides sets of candidate genes as well as candidate wild bean populations that need to be corroborated for their use in increasing the water use efficiency of domesticated beans.


2019 ◽  
Author(s):  
Jayson Paulose ◽  
Oskar Hallatschek

Range expansions lead to distinctive patterns of genetic variation in populations, even in the absence of selection. These patterns and their genetic consequences have been well-studied for populations advancing through successive short-ranged migration events. However, most populations harbor some degree of long-range dispersal, experiencing rare yet consequential migration events over arbitrarily long distances. Although dispersal is known to strongly affect spatial genetic structure during range expansions, the resulting patterns and their impact on neutral diversity remain poorly understood. Here, we systematically study the consequences of long-range dispersal on patterns of neutral variation during range expansion in a class of dispersal models which spans the extremes of local (effectively short-ranged) and global (effectively well-mixed) migration. We find that sufficiently long-ranged dispersal leaves behind a mosaic of monoallelic patches, whose number and size are highly sensitive to the distribution of dispersal distances. We develop a coarse-grained model which connects statistical features of these spatial patterns to the evolution of neutral diversity during the range expansion. We show that growth mechanisms that appear qualitatively similar can engender vastly different outcomes for diversity: depending on the tail of the dispersal distance distribution, diversity can either be preserved (i.e. many variants survive) or lost (i.e. one variant dominates) at long times. Our results highlight the impact of spatial and migratory structure on genetic variation during processes as varied as range expansions, species invasions, epidemics, and the spread of beneficial mutations in established populations.


2013 ◽  
Vol 35 (2) ◽  
pp. 251
Author(s):  
Lisa Cawthen

The white-striped freetail bat (Austronomus australis) is distributed throughout mainland Australia, but historically has not been known from the island of Tasmania, off south-eastern mainland Australia. Between 2009 and 2012, echolocation calls identified as those of A. australis were recorded in Tasmania during bat call surveys. There are three hypotheses that could explain the discovery of this species in Tasmania: that A. australis is a previously undetected resident; it is a vagrant; or it is undergoing a southwards range expansion or shift. Based on the limited evidence available, including this species’ long-range flight capabilities (including over open water out to sea), I suggest that this species is a periodic vagrant to Tasmania and that monitoring is necessary to identify whether this species is undergoing a southwards range extension into Tasmania.


1983 ◽  
Vol 28 (11) ◽  
pp. 6545-6547 ◽  
Author(s):  
M. A. Gusmão ◽  
W. K. Theumann

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