Genetic consequences of being a dwarf: do evolutionary changes in life-history traits influence gene flow patterns in populations of the world’s smallest goldenrod?

Abstract Background and Aims Contrasting life-history traits can evolve through generations of dwarf plant ecotypes, yet such phenotypic changes often involve decreased plant size and reproductive allocation, which can configure seed dispersal patterns and, subsequently, population demography. Therefore, evolutionary transitions to dwarfism can represent good study systems to test the roles of life-history traits in population demography by comparing genetic structure between related but phenotypically divergent ecotypes. Methods In this study, we examined an ecotypic taxon pair of the world’s smallest goldenrod (stem height 2.6 cm) in alpine habitats and its closely related lowland taxon (30–40 cm) found on Yakushima Island, Japan. Genetic variation in chloroplast DNA sequences, nuclear microsatellites and genome-wide single-nucleotide polymorphisms were used to investigate 197 samples from 16 populations, to infer the population genetic demography and compare local genetic structure of the ecotypes. Key Results We found a pronounced level of genetic differentiation among alpine dwarf populations, which were much less geographically isolated than their lowland counterparts. In particular, several neighbouring dwarf populations (located ~500 m apart) harboured completely different sets of chloroplast haplotypes and nuclear genetic clusters. Demographic modelling revealed that the dwarf populations have not exchanged genes at significant levels after population divergence. Conclusions These lines of evidence suggest that substantial effects of genetic drift have operated on these dwarf populations. The low-growing stature and reduced fecundity (only 3.1 heads per plant) of the dwarf plants may have reduced gene flow and rare long-distance seed dispersal among habitat patches, although the effects of life-history traits require further evaluation using ecological approaches.

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Mountains as barriers to gene flow in amphibians: Quantifying the differential effect of a major mountain ridge on the genetic structure of four sympatric species with different life history traits

Journal of Biogeography ◽

10.1111/jbi.13132 ◽

2017 ◽

Vol 45 (2) ◽

pp. 318-331 ◽

Cited By ~ 12

Author(s):

Gregorio Sánchez-Montes ◽

Jinliang Wang ◽

Arturo H. Ariño ◽

Íñigo Martínez-Solano

Keyword(s):

Life History ◽

Gene Flow ◽

Genetic Structure ◽

Differential Effect ◽

Life History Traits ◽

Sympatric Species ◽

Mountain Ridge

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Significant genetic structure despite high vagility revealed through mitochondrial phylogeography of an Australian freshwater turtle (Chelodina longicollis)

Marine and Freshwater Research ◽

10.1071/mf14102 ◽

2015 ◽

Vol 66 (11) ◽

pp. 1045 ◽

Cited By ~ 2

Author(s):

K. Hodges ◽

S. Donnellan ◽

A. Georges

Keyword(s):

Life History ◽

Gene Flow ◽

Genetic Structure ◽

Life History Traits ◽

Isolation By Distance ◽

Phylogeographic Structure ◽

Freshwater Turtle ◽

Freshwater Species ◽

Chelodina Longicollis ◽

Australian Freshwater

Restriction to the freshwater environment plays a dominant role in the population genetic structure of freshwater fauna. In taxa with adaptations for terrestriality, however, the restrictions on dispersal imposed by drainage divides may be overcome. We investigate the mitochondrial phylogeographic structure of the eastern long-necked turtle (Chelodina longicollis), a widespread Australian freshwater obligate with strong overland dispersa\l capacity and specific adaptations to terrestriality. We predict that such characteristics make this freshwater species a strong candidate to test how life-history traits can drive gene flow and interbasin connectivity, overriding the constraining effects imposed by hydrological boundaries. Contrary to expectations, and similar to low-vagility freshwater vertebrates, we found two ancient mitochondrial haplogroups with clear east–west geographic partitioning either side of the Great Dividing Range. Each haplogroup is characterised by complex genetic structure, demographically stable subpopulations, and signals of isolation by distance. This pattern is overlaid with signatures of recent gene flow, likely facilitated by late Pleistocene and ongoing anthropogenic landscape change. We demonstrate that the divergent effects of landscape history can overwhelm the homogenising effects of life-history traits that connect populations, even in a highly vagile species.

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