Embryonic stem cells have the ability to remain undifferentiated and proliferate indefinitely in vitro while maintaining the potential to differentiate into derivatives of all three embryonic germ layers. Here we report the derivation of a cloned cell line (R278.5) from a rhesus monkey blastocyst that remains undifferentiated in continuous passage for >1 year, maintains a normal XY karyotype, and expresses the cell surface markers (alkaline phosphatase, stage-specific embryonic antigen 3, stage-specific embryonic antigen 4, TRA-1-60, and TRA-1-81) that are characteristic of human embryonal carcinoma cells. R278.5 cells remain undifferentiated when grown on mouse embryonic fibroblast feeder layers but differentiate or die in the absence of fibroblasts, despite the presence of recombinant human leukemia inhibitory factor. R278.5 cells allowed to differentiate in vitro secrete bioactive chorionic gonadotropin into the medium, express chorionic gonadotropin a-and ,8-subunit mRNAs, and express a-fetoprotein mRNA, indicating trophoblast and endoderm differentiation. When injected into severe combined immunodeficient mice, R278.5 cells consistently differentiate into derivatives of all three embryonic germ layers. These results define R278.5 cells as an embryonic stem cell line, to our knowledge, the first to be derived from any primate species.
We report the derivation of eight pluripotent cell lines from common marmoset (Callithrix jacchus) blastocysts. These cell lines are positive for a series of markers (alkaline phosphatase, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81) that characterize undifferentiated human embryonal carcinoma cells and rhesus embryonic stem cells. All eight cell lines had a modal chromosome number of 46; seven cell lines were XX and one was XY. Two cell lines (Cj11 and Cj62) were cultured continuously for over a year and remained undifferentiated and euploid. In the absence of fibroblast feeder layers, these cell lines differentiated to multiple cell types, even in the presence of leukemia inhibiting factor. Differentiated cells secreted bioactive CG into the culture medium and expressed alpha-CG, beta-CG, and alpha-fetoprotein mRNA, indicating trophoblast and endoderm differentiation. Bioactive CG secretion in differentiating cells was increased substantially in the presence of GnRH agonist D-Trp6-Pro9-NHEt. When grown at high densities, these cells formed embryoid bodies with a close resemblance to early postimplantation embryos, including the formation of a yolk sac, amnion, and an embryonic disc with an early primitive streak. These results make these pluripotent cells strong candidates for marmoset embryonic stem cells.
Measurements of growth, plasma progesterone and testosterone levels, and copulatory behaviour were obtained from captive marmosets from birth until 600-800 days of age. Body weight and knee-to-heel length were similar for both sexes. Males exhibited a neonatal testosterone surge from 15-100 days and testosterone levels began to rise again, coincident with the growth of the testis, at about 250 days. The males were copulating by 400-500 days of age. Paired females were apparently ovulating and able to conceive from about 400 days. In peer groups, only the dominant female became pregnant, because subordinate females failed to ovulate.
Evolutionary radiations are prominent and pervasive across many plant lineages in diverse geographical and ecological settings; in neotropical rainforests there is growing evidence suggesting that a significant fraction of species richness is the result of recent radiations. Understanding the evolutionary trajectories and mechanisms underlying these radiations demands much greater phylogenetic resolution than is currently available for these groups. The neotropical tree genus Inga (Leguminosae) is a good example, with ~300 extant species and a crown age of 2–10 MY, yet over 6 kb of plastid and nuclear DNA sequence data gives only poor phylogenetic resolution among species. Here we explore the use of larger-scale nuclear gene data obtained though targeted enrichment to increase phylogenetic resolution within Inga. Transcriptome data from three Inga species were used to select 264 nuclear loci for targeted enrichment and sequencing. Following quality control to remove probable paralogs from these sequence data, the final dataset comprised 259,313 bases from 194 loci for 24 accessions representing 22 Inga species and an outgroup (Zygia). Bayesian phylogenies reconstructed using either all loci concatenated or a gene-tree/species-tree approach yielded highly resolved phylogenies. We used coalescent approaches to show that the same targeted enrichment data also have significant power to discriminate among alternative within-species population histories within the widespread species I. umbellifera. In either application, targeted enrichment simplifies the informatics challenge of identifying orthologous loci associated with de novo genome sequencing. We conclude that targeted enrichment provides the large volumes of phylogenetically-informative sequence data required to resolve relationships within recent plant species radiations, both at the species level and for within-species phylogeographic studies.
1. How food webs are structured will affect how species dynamically interact. To date, the construction of quantitative food webs has largely been based on morphological species characters. Yet, recent work suggests that the use of molecular characters may change our perception of both species limits and species identity.2. Focusing on an assemblage of natural enemies of specialist herbivores, we used DNA sequence ‘barcode’ identification for three purposes: to screen the focal web for morphologically cryptic species, to catch misidentified individuals and to re‐examine key descriptors of food web structure.3. Based on morphological characters, we were able to distinguish 51 parasitoid species and 5 inquilines. Molecular markers revealed four morphologically cryptic parasitoid taxa and completely changed our view of species limits among the inquilines, defining six molecular operational taxonomic units (MOTUs) with little resemblance to the original five morphospecies.4. In total, the use of DNA barcode information changed the species designation of 31% of the sequenced individuals. However, measures of food web structure changed relatively little, reflecting the fact that the cryptic taxa detected by us accounted for only a minor proportion of interactions in the overall food web. Qualitatively, web metrics suggested higher specialisation of parasitoid species in molecularly informed than in purely morpohologically‐based webs.5. Taken together, this study suggests that the added resolution offered by molecular information contributes a new level of precision to food web studies. Overall, it depicts interactions within the food web as more specialised than revealed by morphological species characters. Importantly, molecular markers will also allow us to match morphologically cryptic taxa sampled among regions, and thereby to compare the ecological role of individual species in different communities.
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