Intraspecific genetic variation of Batrachospermum gelatinosum (Batrachospermales, Rhodophyta) in eastern North America

Phycologia ◽  
2010 ◽  
Vol 49 (5) ◽  
pp. 501-507 ◽  
Author(s):  
Denise L. House ◽  
Alexander M. Vandenbroek ◽  
Morgan L. Vis
1982 ◽  
Vol 60 (10) ◽  
pp. 1928-1937 ◽  
Author(s):  
L. Hume ◽  
P. B. Cavers

Populations of Rumex crispus were sampled from eastern North America and Europe. The relative amounts of genetic variation and plasticity were examined, using 58 plant characters. About 61% of the total variation occurring in the experimental plants was accounted for by plasticity. The remaining 26% and 13% occurred within populations and among widespread populations, respectively. At the local level, there was little difference between variation occurring within genotypes and that within families (between maternal siblings). This suggests that the species is predominantly inbreeding. The majority of genetic variation occurs within populations at both the local and species' range levels.It was concluded that the species has large amounts of both flexibility and genetic heterogeneity. This adaptive strategy enables the species to survive under a very wide range of environmental situations and largely accounts for its becoming one of the most widely distributed plants in the world.


2018 ◽  
Vol 7 (17) ◽  
Author(s):  
Lori R. Shapiro ◽  
Andres Andrade ◽  
Erin D. Scully ◽  
Jorge Rocha ◽  
Joseph N. Paulson ◽  
...  

Erwinia tracheiphila is a bacterial plant pathogen emerging in eastern North America. To aid in understanding genetic variation within E. tracheiphila, here we sequence the first reference genome of an infected muskmelon (Cucumis melo).


2004 ◽  
Vol 82 (3) ◽  
pp. 316-321 ◽  
Author(s):  
Steven R Griffin ◽  
Spencer CH Barrett

Trillium erectum L. is an insect-pollinated understory herb widespread in forests of eastern North America. Marker gene studies indicate that the species has a mixed mating system, but aspects of population genetic structure have not been investigated. Using 10 allozyme loci, we measured genetic variation within and among 23 populations sampled from throughout the species' range. Overall, T. erectum displayed moderate levels of genetic diversity in comparison with other herbaceous plants. The percentage of loci that were polymorphic was 52%, with average values (±SE) of 1.20 ± 0.02, 0.08 ± 0.01, and 0.13 ± 0.01 for the number of alleles per locus (A), observed heterozygosity (Ho), and expected heterozygosity (He), respectively. There was evidence of inbreeding within populations (Fis = 0.39, 95% CI 0.26–0.55) and significant population differentiation (Fst = 0.16, 0.05–0.24). Analysis of genetic data provided no evidence of isolation by distance, and together with the occurrence of population subdivision, this suggests that there is relatively limited contemporary gene flow among populations. Northern populations of T. erectum tended to have less genetic variability than southern populations, probably as a result of historical factors associated with post glacial migration. Limited opportunities for gene dispersal as a result of low plant densities, the capacity for self-fertilization, and local seed dispersal by ants are likely to be the main factors maintaining contemporary patterns of genetic variation in T. erectum. Key words: allozymes, genetic diversity, gene flow, population genetic structure, Trillium.


1986 ◽  
Vol 6 (3) ◽  
pp. 227-243 ◽  
Author(s):  
Andrew L. Christenson

Although the interest in shell middens in North America is often traced to reports of the discoveries in Danish kjoekkenmoeddings in the mid-nineteenth century, extensive shell midden studies were already occurring on the East Coast by that time. This article reviews selected examples of this early work done by geologists and naturalists, which served as a foundation for shell midden studies by archaeologists after the Civil War.


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