Cell volumes were calculated for 8 species of marine cryptophytes grown under full-spectrum, blue, green, or red light during laboratory-based growth experiments in 2018

Dataset: Cryptophyte Cell VolumesCell volumes were calculated for 8 species of marine cryptophytes grown under full-spectrum, blue, green, or red light during laboratory-based growth experiments conducted in February of 2018. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/870161NSF Division of Environmental Biology (NSF DEB) DEB-154255

De novo transcriptome assembly of the green alga Ankistrodesmus falcatus.

Ankistrodesmus falcatus is a globally distributed freshwater chlorophyte that is a candidate for biofuel production, is used to study the effects of toxins on aquatic communities, and is used as food in zooplankton research. Each of these research fields is transitioning to genomic tools. We created a reference transcriptome for of A. falcatus using NextGen sequencing and de novo assembly methods including Trinity, Velvet-Oases, and EvidentialGene. The assembled transcriptome has a total of 17,997 contigs, an N50 value of 2,462, and a GC content of 64.8%. BUSCO analysis recovered 83.3% of total chlorophyte BUSCOs and 82.5% of the eukaryotic BUSCOs. A portion (7.9%) of these supposedly single-copy genes were found to have transcriptionally active, distinct duplicates. We annotated the assembly using the dammit annotation pipeline, resulting in putative functional annotation for 68.89% of the assembly. Using available rbcL sequences from 16 strains (10 species) of Ankistrodesmus, we constructed a neighbor-joining phylogeny to illustrate genetic distances of our A. falcatus strain to other members of the genus. This assembly will be valuable for researchers seeking to identify Ankistrodesmus sequences in metatranscriptomic and metagenomic field studies and in experiments where separating expression responses of zooplankton and their algal food sources through bioinformatics is important

Global DNA cytosine methylation variation in Spartina alterniflora at North Inlet, SC.

Spartina alterniflora, marsh grass, is a vegetative apomicticly-reproducing halophyte native to marshes along the east coast of the United States and invasive across the world. S. alterniflora provides many ecosystem services including, but not limited to, water filtration, habitats for invertebrates, and sediment retention. Widespread diebacks of longstanding marsh grass colonies launched extensive investigations into probable mechanisms leading to patchy diebacks. There is still current debate as to the causes of a marsh dieback but environmental stress is acknowledged as a constant. Spatial epigenetic variation could contribute to variation of stress susceptibility, but the scale and structure of epigenetic variation is unknown. The current study investigates patterns of epigenetic variation in a natural population of S. alterniflora. This study examines variation of global DNA methylation within and among clones of the marsh grass Spartina alterniflora using an ELISA-like microplate reaction and observed significant heterogeneity of global DNA methylation within and among clones of S. alterniflora across the North Inlet basin, as well as significant differences of global methylation between adults and sexually produced seedlings. The present study also characterized differences for plants in a section of the population that experienced an acute marsh dieback in the year 2001 and have subsequently recolonized, finding a significant positive correlation between cytosine methylation and time period of colonization. The significant heterogeneity of global DNA methylation both within and among clones observed within this natural population of S. alterniflora and potential impacts from hypersaline environments at North Inlet suggests the need for more in-depth epigenetic studies to fully understand DNA methylation within an ecological context. Future studies should consider the effects of varying saline conditions on both global DNA and gene specific methylation

Data from: Selection on incremental variation of eye size in a wild population of Daphnia

Several studies of eye morphology have analyzed macroevolutionary patterns in the diversity of eyes, and though these studies are often linked to environment or behavior, they provide only indirect evidence of selection. Specific data to show the microevolutionary potential for adaptation by natural selection in eye morphology has been lacking. We document directional selection on eye size, an important determinant of visual capabilities, in a wild population of the freshwater microcrustacean Daphnia. We show that even slight changes in eye size may have major consequences for fitness. An increase of eye diameter of 19.9 μm – slightly more than one standard deviation – is associated with an increase in clutch size of one egg, or an increase of nearly 20% of the mean clutch size. Furthermore, relative eye size is genetically variable, and thus could evolve in response to the observed selective pressure. We conclude that selection on incremental variation in eye size may have led to differences observed on broader taxonomic scales

Correlated responses to clonal selection in populations of Daphnia pulicaria

Data from a life table of 79 clones of Daphnia pulicaria. Clone means are provided, as clone was the primary unit of replication

Eye diameter and body length measures on lab-reared Daphnia obtusa for broad-sense heritability estimation

Eye diameter (um) and body length (um) measurements from a common garden experiment on a number of clones of Daphnia obtusa isolated from ponds in Congaree National Park, South Carolina. Each row corresponds to associated identifiers and measurements for a single individual Daphnia. Pond of origin indicates the name of the pond that the original clone was isolated from. D. obtusa clone refers to the name of the clone (pond abbreviation and a number for specific identity). Daphnia size class was determined as small (≤900 μm), medium (901 μm -1399 μm), and adult (≥1400 μm). These size classes reflect ontogenetic growth from juveniles to adults

Rates of Recombination in the Ribosomal DNA of Apomictically Propagated Daphnia obtusa Lines

Ribosomal (r)DNA undergoes concerted evolution, the mechanisms of which are unequal crossing over and gene conversion. Despite the fundamental importance of these mechanisms to the evolution of rDNA, their rates have been estimated only in a few model species. We estimated recombination rate in rDNA by quantifying the relative frequency of intraindividual length variants in an expansion segment of the 18S rRNA gene of the cladoceran crustacean, Daphnia obtusa, in four apomictically propagated lines. We also used quantitative PCR to estimate rDNA copy number. The apomictic lines were sampled every 5 generations for 90 generations, and we considered each significant change in the frequency distribution of length variants between time intervals to be the result of a recombination event. Using this method, we calculated the recombination rate for this region to be 0.02–0.06 events/generation on the basis of three different estimates of rDNA copy number. In addition, we observed substantial changes in rDNA copy number within and between lines. Estimates of haploid copy number varied from 53 to 233, with a mean of 150. We also measured the relative frequency of length variants in 30 lines at generations 5, 50, and 90. Although length variant frequencies changed significantly within and between lines, the overall average frequency of each length variant did not change significantly between the three generations sampled, suggesting that there is little or no bias in the direction of change due to recombination

Fitness effects of spontaneous mutations in a warming world

Spontaneous mutations fuel evolutionary processes and differ in consequence, but the consequences depend on the environment. Biophysical considerations of protein thermostability predict that warm temperatures may systematically increase the deleteriousness of mutation. We sought to test whether mutation reduced fitness more when measured in an environment that reflected climate change projections for temperature. We investigated the effects of spontaneous mutations on life history, size, and fitness in 21 mutation accumulation lines and 12 control lines of Daphnia pulex at standard and elevated (+4℃) temperatures. Warmer temperature accelerated life history and reduced body length and clutch sizes. Mutation led to reduced mean clutch sizes and fitness estimates at both temperatures. We found no evidence of a systematic temperature–mutation interaction on trait means, although some lines showed evidence of beneficial mutation at one temperature and deleterious mutation at the other. However, trait variances are also influenced by mutation, and we observed increased variances due to mutation for most traits. For variance of the intrinsic rate of increase and some reproductive traits, we found significant temperature–mutation interactions, with a larger increase due to mutation in the warmer environment. This suggests that selection on new mutations will be more efficient at elevated temperatures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/168239/1/evo14208-sup-0001-SuppMat.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168239/2/evo14208_am.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/168239/3/evo14208.pd

Eye diameter, body length, and clutch size measurements for D. obtusa isolated from Knobby Knees Pond, Congaree National Park, South Carolina

Eye diameter (um), body length (um), and clutch size (number of eggs) measurements on a wild population of Daphnia obtusa from Knobby Knees (KNB) Pond, Congaree National Park, South Carolina. Each data row corresponds to the associated measures for a single D. obtusa from KNB Pond. Clutch size was measured from living individuals within 36 hours of capture. Animals were immediately preserved in ethanol and marked following clutch counts. Eye diameter and body length were then measured on preserved individuals