AFLP and ISSR analysis reveals high genetic variation and inter-population differentiation in fragmented populations of the endangered Litsea szemaois (Lauraceae) from Southwest China

AbstractEfficient use of any breeding resources requires a good understanding of the genetic value of the founder breeding materials for predicting the gain and diversity in future generations. This study evaluates the distribution of genetic variation and level of relatedness among and within nine breeding populations of Norway spruce for Northern Sweden using nuclear microsatellite markers. A sample set of 456 individuals selected from 140 stands were genotyped with 15 SSR loci. Over all loci each individual was identified with unique multilocus genotype. High genetic diversity (average He=0.820) and low population differentiation (FST=0.0087) characterized this material. Although low in FST, the two northernmost populations were clustered as a distinct group diverged from the central populations. The population differentiation pattern corresponds well with the post glacial migration history of Norway spruce and the current gene flow and human activity in the region. The average inbreeding coefficient was 0.084 after removal loci with high frequency of null alleles. The estimated relatedness of the trees gathered in the breeding populations was very low (average kinship coefficient 0.0077) and not structured. The high genetic variation and low and not structured relatedness between individuals found in the breeding populations confirm that the Norway spruce breeding stock for northern Sweden represent valuable genetic resources for both long-term breeding and conservation programs.

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Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2014.0370 ◽

2014 ◽

Vol 281 (1790) ◽

pp. 20140370 ◽

Cited By ~ 31

Author(s):

Dylan J. Fraser ◽

Paul V. Debes ◽

Louis Bernatchez ◽

Jeffrey A. Hutchings

Keyword(s):

Genetic Variation ◽

Habitat Fragmentation ◽

Population Size ◽

Brook Trout ◽

Small Populations ◽

Adaptive Genetic Variation ◽

Genetic Population ◽

Fragmented Populations ◽

Large Populations ◽

Adaptive Differentiation

Whether and how habitat fragmentation and population size jointly affect adaptive genetic variation and adaptive population differentiation are largely unexplored. Owing to pronounced genetic drift, small, fragmented populations are thought to exhibit reduced adaptive genetic variation relative to large populations. Yet fragmentation is known to increase variability within and among habitats as population size decreases. Such variability might instead favour the maintenance of adaptive polymorphisms and/or generate more variability in adaptive differentiation at smaller population size. We investigated these alternative hypotheses by analysing coding-gene, single-nucleotide polymorphisms associated with different biological functions in fragmented brook trout populations of variable sizes. Putative adaptive differentiation was greater between small and large populations or among small populations than among large populations. These trends were stronger for genetic population size measures than demographic ones and were present despite pronounced drift in small populations. Our results suggest that fragmentation affects natural selection and that the changes elicited in the adaptive genetic composition and differentiation of fragmented populations vary with population size. By generating more variable evolutionary responses, the alteration of selective pressures during habitat fragmentation may affect future population persistence independently of, and perhaps long before, the effects of demographic and genetic stochasticity are manifest.

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Population differentiation and genetic variation inform translocation decisions for Liatris scariosa var. novae-angliae, a rare New England grassland perennial

Biological Conservation ◽

10.1016/j.biocon.2005.01.021 ◽

2005 ◽

Vol 124 (2) ◽

pp. 155-167 ◽

Cited By ~ 19

Author(s):

Kelly Gravuer ◽

Eric von Wettberg ◽

Johanna Schmitt

Keyword(s):

Genetic Variation ◽

New England ◽

Population Differentiation

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Populations Are Differentiated in Biological Rhythms without Explicit Elevational Clines in the Plant Mimulus laciniatus

Journal of Biological Rhythms ◽

10.1177/0748730420936408 ◽

2020 ◽

Vol 35 (5) ◽

pp. 452-464

Author(s):

Päivi H. Leinonen ◽

Matti J. Salmela ◽

Kathleen Greenham ◽

C. Robertson McClung ◽

John H. Willis

Keyword(s):

Genetic Variation ◽

Circadian Clock ◽

Sierra Nevada ◽

Population Differentiation ◽

Plant Traits ◽

Population Level ◽

Day Length ◽

Circadian Period ◽

Population Means ◽

Seasonal Responses

Environmental variation along an elevational gradient can yield phenotypic differentiation resulting from varying selection pressures on plant traits related to seasonal responses. Thus, genetic clines can evolve in a suite of traits, including the circadian clock, that drives daily cycling in varied traits and that shares its genetic background with adaptation to seasonality. We used populations of annual Mimulus laciniatus from different elevations in the Sierra Nevada in California to explore among-population differentiation in the circadian clock, flowering responses to photoperiod, and phenological traits (days to cotyledon emergence, days to flowering, and days to seed ripening) in controlled common-garden conditions. Further, we examined correlations of these traits with environmental variables related to temperature and precipitation. We observed that the circadian period in leaf movement was differentiated among populations sampled within about 100 km, with population means varying by 1.6 h. Significant local genetic variation occurred within 2 populations in which circadian period among families varied by up to 1.8 h. Replicated treatments with variable ecologically relevant photoperiods revealed marked population differentiation in critical day length for flowering that ranged from 11.0 to 14.1 h, corresponding to the time period between late February and mid-May in the wild. Flowering time varied among populations in a 14-h photoperiod. Regardless of this substantial population-level diversity, obvious linear clinality in trait variability across elevations could not be determined based on our genotypic sample; it is possible that more complex spatial patterns of variation arise in complex terrains such as those in the Sierra Nevada. Moreover, we did not find statistically significant bivariate correlations between population means of different traits. Our research contributes to the understanding of genetic variation in the circadian clock and in seasonal responses in natural populations, highlighting the need for more comprehensive investigations on the association between the clock and other adaptive traits in plants.

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