In the Light of Evolution Volume X: Comparative Phylogeography (2017) / Chapter Skim
Currently Skimming:
16 Union of Phylogeography and Landscape Genetics - Leslie J. Rissler
16 Union of Phylogeography and Landscape Genetics - Leslie J. Rissler
Pages 313-330
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 313... ...
, early studies by Dobzhansky on the "microgeographic races" of Linanthus parryae in the Mojave Desert of California and Drosophila pseudoobscura across the western United States presaged the fields by over 40 years. Recent advances in theory, models, and methods have allowed researchers to better synthesize ecological and evolutionary processes in their quest to answer some of the most basic questions in biology.
|
From page 314... ...
and landscape genetics are considered separate fields: But are they? One of the earliest papers examining phenotypic variation (albeit not genetic variation, although this was assumed)
|
From page 315... ...
(2009) in the Australian Wet Tropics rainforest also suggested that shared suture zones were ideal natural laboratories to study the processes driving divergence, reproductive isolation, and speciation.
|
From page 316... ...
and Dyer (2015) separating populations in the Great Plains from populations in the Pacific Coastal regions (figure without suture zone is figure 1 from Dobzhansky et al., 1966)
|
From page 317... ...
because phylogeographers study the geographic distributions of genealogical lineages, rather than species, per se. This integration was possible because of the technical developments of the past half-century that allow the measurement of genetic variation at fine spatial scales, along with the growing realization that the diversification of species can be explained by p opulation-level evolutionary processes (reviewed in Coyne and Orr, 2004)
|
From page 318... ...
Their multilocus polygenic analysis identified candidate loci potentially under thermal selection, and their studies highlight the usefulness of integrating genomic, phenotypic, and environmental data to disentangle historical and contemporary evolutionary and ecological processes. THE WAYS IN WHICH PHYLOGEOGRAPHY AND LANDSCAPE GENETICS ARE THOUGHT TO DIFFER Both phylogeography and landscape genetics fall squarely within the realm of biogeography -- "the science that attempts to document and understand spatial patterns of biological diversity" (Lomolino et al., 2010)
|
From page 319... ...
Although a detailed discussion of analytical methods used in the two fields is beyond the scope of this chapter (Storfer et al., 2007) , I note that phylogeographic studies tend to emphasize genealogical lineages with a more explicit appreciation of history whereas landscape genetics studies focus on spatially explicit population genetic analyses, with little regard for genealogical relationships of closely related lineages or species (but see Vandergast et al., 2007; Koscinski et al., 2009; Swaegers et al., 2014, 2015)
|
From page 320... ...
Typical landscape genetics studies are less interested in physiography, history, climate, and geology and more focused on a particular species' or population's dispersal across space and how those factors influence movement and gene flow. These spaces are often distilled into distance matrices that can be ecological (e.g., environmental climate data -- past, present, or future)
|
From page 321... ...
use as input georeferenced specimen data, typically from natural history collections (e.g., www.gbif.org/) , and spatially explicit environmental data, often from publically accessible sites like WorldClim (www.worldclim.
|
From page 322... ...
Additional advances have come in the realm of better and faster computer algorithms. For example, understanding current species distributions and genetic diversity requires accounting for variation in population sizes and migration rates across a species' temporal and spatial range, such as in the studies of Knowles and Alvarado-Serrano (2010)
|
From page 323... ...
, relying more heavily on history than current ecological conditions, and landscape genetics is loosely analogous to ecological biogeography, relying more heavily on the latter than the former. Modern biogeography, on the other hand, must necessarily consider both historic and current ecological and evolutionary processes.
|
From page 324... ...
allowed molecular systematists to observe fine-scaled genetic differences within species and allowed evolutionary ecologists to apply knowledge of natural selection and biogeographic barriers in nature to questions about speciation. Today, there are many studies of ecological speciation (e.g., Hendry, 2009)
|
From page 325... ...
Even systematics has been infused with more biogeography in recent years because of the ubiquity of spatially explicit environmental data and publicly accessible georeferenced specimen data from natural history collections. An early comparative phylogeographic analysis of California by Lapointe and Rissler (2005)
|
From page 326... ...
. These kinds of phylogeographic and landscape genetics studies, which integrate geographic and ecological analyses, have spawned new methods in species delimitation that explicitly consider the extent of ecological divergence when diagnosing species (Raxworthy et al., 2007; Rissler and Apodaca, 2007; Leaché et al., 2009; Pelletier et al., 2015)
|
From page 327... ...
with microevolutionary processes (genetic drift, mutation, gene flow, and natural selection) is challenging but would advance fields interested in understanding the distribution of organisms (e.g., biogeography, ecology, evolution, and conservation)
|
From page 328... ...
How much reduction of gene flow, if any, is required to generate new species, and is that gene flow most often reduced by geographic distance, natural selection, or other factors?
|
From page 329... ...
(iv) Can adaptive evolution and genetic diversity keep pace with the scale of current environmental variability and shifts?
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.